Nikki Creations

Google's chatback badge!

2008-09-30T10:14:00.001+05:30

If you have a blog, online profile or some personal web page, would you like to communicate more with your visitors?

Google have launched a new Google talk feature that lets visitors of your web site chat with you! It is called as 'chatback' because instead of you doing all the talking on your blog or web page, your visitors can talk back to you. They could leave comments, but those are public, and hard to use for real conversation. With chatback, its a real time instant message session.

For example, you can ask authors of blog posts here about your doubts or can provide with your quick questions or suggestions!!

To use chatback, you must have a Google talk account.. but your visitors don't need that. Isn't that amazing? They even don't need to have an email address, nor to have ever used instant messaging.

When the visitors visit your site, they will see a badge similar to the one below, showing your online status (available, busy, idle, offline). And, if you are available, they can just click and start chatting.

try this out!

Technically speaking, chatback uses web-based google talk gadget so your visitors don't need to download anything. It opens in a new window so that they can keep on chatting even if they navigate to other pages.

The chatback is not just for the blogs. you can use it on any web page where you are allowed to add HTML code. To get started, visit the chatback start page. Just copy the provided HTML snippet and add it to your web page. Visitors will then see a badge on your site indicating your availability and can click to start chatting with you. If some point in time you don't want to get distracted, just set your online status to 'busy' and visitors won't be able to chat with you, until you change your status back to 'available'.

New Browser from Google:Chrome

2008-09-08T19:04:00.001+05:30

Google have announced plans to take on Microsoft and Firefox with their own browser.
The Google Chrome browser will be based on the existing Webkit rendering engine and integrate not only tab-based browsing but
Google Gears and the latest version of the company’s search technology, called Omnibox.

Omnibox, which will replace the address bar and search bar in the Google Chrome browser, will offer search suggestions,
popular pages and history pages. Omnibox will also automatically replicate a webpage’s own search box, allowing site and
query strings to be entered simultaneously: for instance, entering “amazon”, pressing tab and then the search term will automatically
go to an Amazon search results page for that term.

Google Chrome BrowserThe Google Chrome browser will also include some of the more popular features from existing rivals.
It will have a homepage of nine instant-access shortcut thumbnails along with recent search history and recent tabs.
Tabs themselves will be switched to above the window, not below it as on Firefox. There’ll be a privacy mode - which Google are
calling an “incognito” window - within which no record of surfing will be kept. Malware and phishing will be protected against, with
the Google Chrome browser automatically downloading a constantly updated list of harmful sites in the background.

An updated JavaScript Virtual Machine, called V8, will also be an integral part of the Google Chrome browser,
which has been specially developed in Denmark. It promises to speed up JavaScript and reduce memory bloat,
which will make a significant difference in webapps. It’ll also flag up any core offenders, whether webpages or plug-ins,
that use up more memory than they should. Chrome will allow webapps to create their own, address and toolbar free windows,
better replicating traditional desktop apps and blurring the differentiation between the two.Intended for release as an open-source project,
the Google Chrome browser has no specific release date attached to it. -SlashGear Take Google Chrome for a test drive!

Download It!

Who Writes Linux and Who Supports It

2008-08-26T17:05:00.000+05:30

• Who is Writing Linux?

* Every Linux kernel is being developed by nearly 1,000 developers working for more than 100 different corporations. This is the foundation for the largest distributed software development project in the world.
* Since 2005, the number of active kernel developers has tripled, reflecting the growing importance of Linux in the embedded systems, server, and desktop markets.
* Between 70 and 95 percent of those developers are being paid for their work, dispelling the “hobbyist” myth present from the start of open source development.

• Who is Sponsoring Linux?

More than 70 percent of total contributions to the kernel come from developers working at a range of companies including IBM, Intel, The Linux Foundation, MIPS Technology, MontaVista, Movial, NetApp, Novell and Red Hat. These companies, and many others, find that by improving the kernel they have a competitive edge in their markets.

• How Fast is Linux Developed and Released?

* An average of 3,621 lines of code are added to the kernel tree every day, and a new kernel is released approximately every 2.7 months.
* The kernel, since 2005, has been growing at a steady state of 10 percent per year.

Linux XP Desktop 2008

2008-08-21T17:30:00.000+05:30

Its a simple, reliable and user-friendly system

In the modern dynamically changing world with wide business and personal communications are very important for feeling assured and to have habitual, reliable and comfortable tools for work and communications.

Quickly growing sector of IT-decisions offers set of variants similar tools, but comfort and satisfaction from use similar tools it is not always equal to your expenses for their purchase.

We consider, that modern technologies have reached that level, when the program becomes not simply technical set of bits, and turns in work of art in which it would be desirable to take pleasure everyone minute of work with it. Therefore, we offer for you ergonomic, comfortable and functional workplace � Linux XP Desktop.

Linux XP Desktop makes your computer virus-free, stable and dependable. You'll spend less time fixing your PC and more time using a standard well-known graphical interface to get work done.

* The most user-friendly interface ever made for Linux
* Simple and clear installation and Windows-style setup tools
* Full set of applications for work in the Internet.
* Support of Microsoft Office document formats (WORD, EXCEL and others)
* Useful tools for working with Windows networks and VPN
* Full control of your computer, data and applications
* Stable, dependable and without any reinstallation
* Absolutely virus-free environment
* Free updates through a simple but useful interface (no RPM knowledge is required)

You will always know what programs are running and forget about viruses. A set of Windows-like setup tools allows you to perform system management duties in a way that is familiar to you.

To start working with Linux XP Desktop, your Windows-experience is all you need. You do not have to read tons of files on your screen, buy mountains of manuals, search the Internet for answers or call your Linux-guru every hour for help. Just install Linux XP Desktop and use it.

For More Information Click Here

How can I enable theme support in Windows Server 2003?

2008-08-21T15:00:00.002+05:30

Windows Server 2003 has the theme support services disabled by default.

To enable themes on Windows Server 2003 follow the next steps:

Go to the Services applet in Administrative Tools (or click Start, then Run, and type "services.msc" (without quotes) and click
OK).
Find the "Themes" service, right-click and select Properties, select "Automatic" instead of "Disabled" in the startup type box.
Click Apply.
Right-click the Themes service and select Start.

You can also modify start state and start it from a Command Prompt console by using the following command:
sc config Themes start= auto
sc start Themes (or net start Theme)

For now you only have Luna Blue, Silver and Olive Green to choose from.

Go to Control Panel, select Display and then go to the Appearance tab.
In the "Windows and Buttons" drop-down list select "Windows XP Style". Click Ok.
Now you can choose the color scheme.

Google phone coming in October

2008-08-20T10:50:00.000+05:30

T-Mobile is about to launch the first phone based on Google's Android design. It hopes the new device will compete with Apple's iPhone.

This smartphone will be manufactured by High Tech Computer, a Taiwan-based company. It will have a large touch screen that slides out to reveal a five-row QWERTY keyboard. The device, which will be called the G1, will sell for $150 to T-Mobile customers in the first week of launch before it is offered to other customers at a higher price.

Google developed the Android design to help it expand its successful advertising business into the increasingly lucrative mobile market. It released the parameters to an alliance of mobile phone carriers, developers and manufacturers earlier this year.

Deutsche Telecom's T-Mobile announced in February that it would introduce Android-based phones in the fourth quarter of 2008.

How to change IP address from the Windows command line

2008-08-19T15:31:00.000+05:30

To do the same thing via the command line, use the netsh tool.

After some experimentation, I found that the following two commands were sufficient to give my machine a static IP address and have everything still work ok. The "interface ip set address" command changes the IP to 192.168.1.101 (this address is outside the range allocated by our DHCP server, therefore it will be different to what we had before) and I also had to provide the subnet mask (255.255.255.0), default gateway (192.168.1.5) and a gateway metric. The second command explicitly sets the DNS server to use for name resolution - normally this is done for us by the DHCP server.

netsh interface ip set address "Local Area Connection" static 192.168.1.101 255.255.255.0 192.168.1.5 1
netsh interface ip set dns "Local Area Connection" static 192.168.1.200 primary

To change the interface back to using DHCP and so have it allocated a different IP address

netsh interface ip set address "Local Area Connection" dhcp
netsh interface ip set dns "Local Area Connection" dhcp

Emerging Technologies: Developments in Red Hat Enterprise Linux RealTime

2008-08-18T19:18:00.000+05:30

by Emerging Technologies Team

You may have heard the news from Red Hat’s CTO Brian Stevens’ keynote at the Red Hat Summit that we are building a realtime variant of Red Hat Enterprise Linux. There were a few sessions at the Summit describing our initiative in more detail. For those of you who weren’t present, we’d like to share some realtime info with you here.

We can simplify the primary functional objectives of our realtime initiative down to a few key points:

1. Determinism: provide consistent, repeatable response times
2. Priority: ensure the highest priority processes run first

Sounds rather basic, right?

For most workloads, a properly tuned Red Hat Enterprise Linux kernel (in RHEL 2.1, 3, 4 or 5) meets customer requirements. Typical timing requirements are in the range of millisecond response time. However for the most demanding customer workloads, the requirements are in the microsecond range. To give just a few representative examples:

* Financial Services industry: here time is money. In this highly competitive market, shaving fractions of a second off the time it takes to performs market analytics yields huge advantage. Additionally, there are increasing government regulations for consistency in trading. They don’t want things smelling fishy if some trades take longer than others.
* Federal command and control systems: here, “close enough” isn’t good enough. They need to dependably know that the highest priority application threads will run and complete in predictable periods of time.

The primary reason why the standard Red Hat Enterprise Linux products can’t completely meet the most demanding response time requirements is because there are numerous lengthy kernel codepaths which are non-preemptable. Without getting too technical here, this means that while these non-preemptable kernel codepaths are running, the high priority application threads are not running. Hence these long-running kernel codepaths result in delays in the application running, which is the cause of inconsistent response times (also referred to as non-determinism). In his keynote address at the Summit, Brian displayed a performance chart illustrating that when running a messaging workload on standard Red Hat Enterprise Linux, there was substantial deviation in response times. Whereas when running the realtime kernel, the response times were highly consistent.

Sun's next goal: A Linux ecosystem

2008-08-18T16:12:00.000+05:30

The server and software company launched its servers based on its own UltraSparc T1 "Niagara" chips in December, a major part of a drive to restore its lost lustre and financial strength.

But alongside the hardware launch came a more quiet software push: an attempt to make the Linux and BSD Unix open-source operating systems a serious option for buyers of Sparc-based computers. To promote the technology combination, Sun is trying to coax an accompanying software business into existence.

Sun has had some experience building such software "ecosystems." For example, it's in the process of resurrecting a version of its own Solaris operating system for computers with x86 processors such as Advanced Micro Devices' Opteron. But Sun, which already has several irons in the fire, faces formidable challenges in the Linux and BSD effort.

"The time for Linux on Sparc as any kind of major market phenomenon has come and gone -- over five years ago now, maybe longer," Illuminata analyst Jonathan Eunice said. "It just serves to split the available development resources."

Through projects such as UltraLinux and Aurora Linux, Linux and some BSD variants can already run on Sparc processors. But the products are not commercially relevant for most potential customers. The two major Linux sellers have already pulled back -- Red Hat dropped its Sparc support in 2000, and Novell Suse's last supported version was released in 2002.

Still, Sun has no shortage of gumption. "Linux on Sparc is dead serious," President Jonathan Schwartz said in an e-mail interview. "I'm personally talking to leaders in the community. BSD, too."

The effort is part of Sun's attempt to restore its relevance and financial fortunes by shaking its image as a proprietary technology company. That legacy from the '90s hurt the Santa Clara, California-based company when it missed out on two major growth trends that spanned the rest of the server industry: machines built with x86 processors such as Opteron and Intel's Xeon, and the open-source Linux operating system.

Now, one 180-degree turn later, Sun is making its Solaris an open-source project and plans to do the same with its UltraSparc processor. "To be successful, Solaris has to go beyond Sparc. But also to be successful, Sparc has to go beyond Solaris," said David Yen, who as executive vice president of Sun's Sparc server group is trying to make the chip family "the new industry standard."

Intel to launch Linux-powered mobile Internet device

2008-08-18T16:04:00.001+05:30

Intel is developing its own take on the mini-tablet, with a new ultra-mobile PC platform to be announced at this week's Intel Developer Forum in Beijing. The big surprise? It's based on Linux.

Called a Mobile Internet Device (pic), or MID, the devices will have screen sizes from 4.5 to six inches with a target audience described as "consumers and prosumers" rather than mobile professionals.

The MID2007 platform, currently codenamed McCaslin, will gain a more marketing-friendly moniker closer to next year's release of the products. This is tipped to be an extension of the successful Centrino mobile brand, in the same manner as the recent announcement earlier this month of a higher-end Centrino Pro brand for enterprise-class notebooks incorporating Intel's vPro management technology.

While McCaslin's CPU components -- codenamed Stealey -- will be dual-core processors clocked at 600-800MHz and capable of running Windows XP and Vista, Intel plans for the devices to run an embedded Linux OS but with a mix of open-source and proprietary code in the final products.

Typical MID uses will be "staying in touch", entertainment, information and location-based services. Intel's presentation specifically cites Google Maps and Web-based "office and enterprise applications" in the last two categories. Connectivity will be provided through Wi-Fi and support for wide-area coverage via 3G HSDPA.

MID tablets will run a simplified "finger-friendly" user interface optimised for the small screens, based on the Gnome desktop but with an Intel-developed "master user interface" layer to serve as an equivalent to the desktop.

Developers will next month see the first MID-specific OS -- a tweak of China's RedFlag Linux known as RedFlag MIDINUX -- while the IDF schedule itself includes a stream of "ultra mobile sessions" including one on "Designing for Linux-based mobile Internet devices".

Intel first tipped its hand in the UMPC space at least year's IDF, when it showcased several prototype devices no larger than a paperback book and announced a partnership with Yahoo to deliver a rich Web-based back end of business and personal services.

Microsoft HealthVault

2008-08-14T20:42:00.000+05:30

Microsoft® HealthVault™ is designed to put you in control of your health information.
A free HealthVault account helps you collect, store and share information with family members
and gives you a choice of applications and devices to help manage your fitness, diet and health.

How HealthVault works

HealthVault isn't just a Web site - it's the hub of a network of Web sites, personal health devices
and other services that you can use to help manage your health.
HealthVault lets you store the information in one central place on the Web.
You're in control of what information you store and can decide who else can see, change, or help manage it.
HealthVault never lets other Web sites or programs see or change the information in your
HealthVault record without explicit permission from you or a record custodian invited to share your records.

Click Here For More Information

Platform As A Service: Cloudo

2008-08-14T19:31:00.000+05:30

Platform As A Service: Cloudo

Platform As A Service, or PaaS is the latest development in virtualization. Where companies started to offer applications online (Saas, Software As A Service) and the use of virtual servers is becoming mainstream, more and more companies now offer a complete operating system as a service online.
Cloudo is the latest addition to platform providers. There are several others that have existed for a while now in the consumer market, but to be honest I have no idea if there is a consumer market for this technology. Virtualization is huge in the business market - after offering servers with virtual servers on top even SUN Microsystems now considers offering online platforms for businesses.

So what is so interesting about Cloudo? Why would we want a webbased operating system? Well, something that makes a huge difference is the option to sync your files to the operating system. Until now, nobody else offers this.

There currently is a private beta for developers only, so there's nothing for me there right now. But I will keep an eye on it.

New wireless sensor network keeps tabs on the environment

2008-08-14T19:24:00.000+05:30

New wireless sensor network keeps tabs on the environment

Have you ever wondered what happens in the rainforest when no one is looking?.

Research in the University of Alberta's Faculty of Science may soon be able to answer that question. The departments of computing science and earth and atmospheric science have been working together to create a Wireless Sensor Network that allows for the clandestine data collection of environmental factors in remote locations and its monitoring from anywhere in the world where the Internet is available.

The research team, including Pawel Gburzynski, Mario Nascimento, and Arturo Sanchez-Azofeifa, recently launched EcoNet, a functional model of a WSN for environmental monitoring in the display house in the University of Alberta's Agriculture/Forestry Centre. The display house hosts a small but feature-rich environment that mimics that of a tropical forest. Using a WSN, many sensors can continuously monitor factors like temperature and luminosity and will process, store and transmit data co-operatively and wirelessly with other sensors to generate data that can then be collected and made available to users virtually anywhere on the globe. The sensors represent a technology for scientists to monitor diverse phenomena continuously and inconspicuously.

Having the data continuously monitored by scientists substantially increases the chances of uncovering anomalies early enough to investigate them promptly and thoroughly.........

ClearForest Gnosis: The Future of Web Searches

2008-08-12T20:20:00.000+05:30

ClearForest Gnosis is early example of the possibilities of semantic web searches,
hinting at the facility semantic web applications will allow in the future.
Gnosis, a plugin for Firefox or Internet Explorer (link currently unavailable),
does a real-time semantic search of textual key words.

Gnosis effectively puts a powerful search engine right into the text of any web page you visit.
After processing the page, Gnosis offers a series of hyperlinks, each one operating like a sort of minisearch,
highlighting people, organizations, medical conditions, companies, currency, city, country, or industry terms,
for example. The thematically color-coded hyperlinks link to automatic searches on Google, Wikipedia,
Facebook, Linked In, Reuters News, Technorati and various financial services.

A simple click on the linked word can either Google it, find it in Wikipedia, or,
if it’s a person, easily find their Facebook or LinkedIn page. Another way Gnosis makes searching
easier is it highlights every instance of a word, instead of just the first time, as is usual on most web sites.

At this point Gnosis mainly serves to make searches faster. It allows you to process a site after you’ve gone to it,
or you can choose to automatically search a site by adding its address to the options menu. Not having to leave the text to type in key words certainly allows for a much quicker gathering of contextual information than a traditional search.

Gnosis is part of Thomson Reuters’ semantic web project, OpenCalais, and is integrated into Reuter’s GIST,
a “360-degree” news service, featuring articles, images, and videos. GIST aims to use ClearForest searches to create its context-based news pages.

Journaled File System Technology for Linux

2008-08-12T14:23:00.001+05:30

Journaled File System Technology for Linux

Overview
IBM's journaled file system technology, currently used in IBM enterprise servers, is designed for high-throughput server environments, key to running intranet and other high-performance e-business file servers. IBM is contributing this technology to the Linux open source community with the hope that some or all of it will be useful in bringing the best of journaling capabilities to the Linux operating system.

Developing JFS
JFS is licensed under the GNU General Public License. If there's a feature that you'd like to see added to JFS, consider becoming a part of the JFS development process. Since JFS is an open source project, it's easy to get involved.

Click Here For More Information

Microsoft Surface:New Technology From Microsoft.

2008-08-12T13:44:00.003+05:30

Microsoft Surface (Codename: Milan), is a Multi-touch product from Microsoft which is developed as a
software and hardware combination technology
that allows a user, or multiple users, to manipulate digital content by the use of natural motions,
hand gestures, or physical objects. It was announced on May 29, 2007 at D5 conference.
Initial customers will be in the hospitality businesses, such as restaurants, hotels, retail,
public entertainment venues and the military for tactical overviews.
The preliminary launch was on April 17, 2008, when Surface became available for customer use in AT&T stores.

Overview-
Surface is essentially a Windows Vista PC tucked inside a table, topped with a 30-inch reflective surface
in a clear acrylic frame. A projector underneath the surface projects an image onto its underside,
while five cameras in the machine's housing record reflections of infrared light from human fingertips.
The camera can also recognize objects placed on the surface if those objects have specially-designed "tags"
applied to them. Users can interact with the machine by touching or dragging their fingertips and objects
such as paintbrushes across the screen, or by placing and moving tagged objects.

Surface has been optimized to respond to 52 touches at a time. During a demonstration with a reporter,
Mark Bolger, the Surface Computing group's marketing director, "dipped" his finger in an on-screen paint palette,
then dragged it across the screen to draw a smiley face. Then he used all 10 fingers at once to give the face
a full head of hair.

Using the specially-designed "tags" on objects, Microsoft Surface can automatically offer
additional wine choices tailored to the dinner being eaten based on the type of wine set on the Surface.

Click on following link--
See The Video

Zimbra:-messaging and collaboration

2008-08-08T14:37:00.001+05:30

Zimbra™ Collaboration Suite is a full-featured messaging and collaboration
solution that includes email, address book, calendaring, tasks, and Web
document authoring.

The Zimbra Collaboration Suite is designed to provide an end-to-end mail
solution that is scalable and highly reliable. The messaging architecture is built
with well-known open-system technology and standards and is composed of a
mail server application and a client interface.

The architecture includes the following core advantages:

• Open source integrations. Linux®, Jetty, Postfix, MySQL®, OpenLDAP®.
• Uses industry standard open protocols. SMTP, LMTP, SOAP, XML,
IMAP, POP.
• Modern technology design. Java, JavaScript thin client, DHTML.
• Horizontal scalability. Because each mailbox server includes its own data
store, message store, and set mailbox accounts, you don’t change
anything on existing servers in order to scale the system. To scale for
additional mail accounts, add more servers.
• Browser based client interface. Zimbra Web Client gives users easy
access to all the ZCS features
• Administration console to manage accounts and servers.

Core Functionality

The Zimbra Collaboration Suite is an innovative messaging and collaboration
application that offers the following state-of-the-art messaging and
collaboration solutions:
• Email
• Group Calendars
• Address Books
• Task Management
• Web document management and authoring.

RAID Level in Details

2008-08-07T13:27:00.002+05:30

What is RAID?

RAID allows information to access several disks. RAID uses techniques such as disk striping (RAID Level 0), disk mirroring (RAID Level 1), and disk striping with parity (RAID Level 5) to achieve redundancy, lower latency, increased bandwidth, and maximized ability to recover from hard disk crashes.

RAID consistently distributes data across each drive in the array. RAID then breaks down the data into consistently-sized chunks (commonly 32K or 64k, although other values are acceptable). Each chunk is then written to a hard drive in the RAID array according to the RAID level employed. When the data is read, the process is reversed, giving the illusion that the multiple drives in the array are actually one large drive.

Hardware RAID

The hardware-based array manages the RAID subsystem independently from the host. It presents a single disk per RAID array to the host.

A Hardware RAID device connects to the SCSI controller and presents the RAID arrays as a single SCSI drive. An external RAID system moves all RAID handling "intelligence" into a controller located in the external disk subsystem. The whole subsystem is connected to the host via a normal SCSI controller and appears to the host as a single disk.

RAID controller cards function like a SCSI controller to the operating system, and handle all the actual drive communications. The user plugs the drives into the RAID controller (just like a normal SCSI controller) and then adds them to the RAID controllers configuration, and the operating system won't know the difference.

Software RAID

Software RAID implements the various RAID levels in the kernel disk (block device) code. It offers the cheapest possible solution, as expensive disk controller cards or hot-swap chassis [1] are not required. Software RAID also works with cheaper IDE disks as well as SCSI disks. With today's faster CPUs, Software RAID outperforms Hardware RAID.

The Linux kernel contains an MD driver that allows the RAID solution to be completely hardware independent. The performance of a software-based array depends on the server CPU performance and load.

To learn more about Software RAID, here are the key features:

*

Threaded rebuild process
*

Kernel-based configuration
*

Portability of arrays between Linux machines without reconstruction
*

Backgrounded array reconstruction using idle system resources
*

Hot-swappable drive support
*

Automatic CPU detection to take advantage of certain CPU optimizations

RAID Levels and Linear Support

RAID supports various configurations, including levels 0, 1, 4, 5, and linear. These RAID types are defined as follows:

*

Level 0 — RAID level 0, often called "striping," is a performance-oriented striped data mapping technique. This means the data being written to the array is broken down into strips and written across the member disks of the array, allowing high I/O performance at low inherent cost but provides no redundancy. The storage capacity of a level 0 array is equal to the total capacity of the member disks in a Hardware RAID or the total capacity of member partitions in a Software RAID.
*

Level 1 — RAID level 1, or "mirroring," has been used longer than any other form of RAID. Level 1 provides redundancy by writing identical data to each member disk of the array, leaving a "mirrored" copy on each disk. Mirroring remains popular due to its simplicity and high level of data availability. Level 1 operates with two or more disks that may use parallel access for high data-transfer rates when reading but more commonly operate independently to provide high I/O transaction rates. Level 1 provides very good data reliability and improves performance for read-intensive applications but at a relatively high cost. [2] The storage capacity of the level 1 array is equal to the capacity of one of the mirrored hard disks in a Hardware RAID or one of the mirrored partitions in a Software RAID.
*

Level 4 — Level 4 uses parity [3] concentrated on a single disk drive to protect data. It is better suited to transaction I/O rather than large file transfers. Because the dedicated parity disk represents an inherent bottleneck, level 4 is seldom used without accompanying technologies such as write-back caching. Although RAID level 4 is an option in some RAID partitioning schemes, it is not an option allowed in Red Hat Enterprise Linux RAID installations. [4] The storage capacity of Hardware RAID level 4 is equal to the capacity of member disks, minus the capacity of one member disk. The storage capacity of Software RAID level 4 is equal to the capacity of the member partitions, minus the size of one of the partitions if they are of equal size.
*

Level 5 — This is the most common type of RAID. By distributing parity across some or all of an array's member disk drives, RAID level 5 eliminates the write bottleneck inherent in level 4. The only performance bottleneck is the parity calculation process. With modern CPUs and Software RAID, that usually is not a very big problem. As with level 4, the result is asymmetrical performance, with reads substantially outperforming writes. Level 5 is often used with write-back caching to reduce the asymmetry. The storage capacity of Hardware RAID level 5 is equal to the capacity of member disks, minus the capacity of one member disk. The storage capacity of Software RAID level 5 is equal to the capacity of the member partitions, minus the size of one of the partitions if they are of equal size.
*

Linear RAID — Linear RAID is a simple grouping of drives to create a larger virtual drive. In linear RAID, the chunks are allocated sequentially from one member drive, going to the next drive only when the first is completely filled. This grouping provides no performance benefit, as it is unlikely that any I/O operations will be split between member drives. Linear RAID also offers no redundancy and, in fact, decreases reliability — if any one member drive fails, the entire array cannot be used. The capacity is the total of all member disks.

Linux File System Structure.

2008-08-05T14:40:00.002+05:30

Overview of File System Hierarchy Standard (FHS)

Red Hat Enterprise Linux uses the Filesystem Hierarchy Standard (FHS) file system structure, which defines the names, locations, and permissions for many file types and directories.

The FHS document is the authoritative reference to any FHS-compliant file system, but the standard leaves many areas undefined or extensible. This section is an overview of the standard and a description of the parts of the file system not covered by the standard.

Compliance with the standard means many things, but the two most important are compatibility with other compliant systems and the ability to mount a /usr/ partition as read-only. This second point is important because the directory contains common executables and should not be changed by users. Also, since the /usr/ directory is mounted as read-only, it can be mounted from the CD-ROM or from another machine via a read-only NFS mount.

FHS Organization

1) The /boot/ Directory

The /boot/ directory contains static files required to boot the system, such as the Linux kernel. These files are essential for the system to boot properly.

2)The /dev/ Directory

The /dev/ directory contains device nodes that either represent devices that are attached to the system or virtual devices that are provided by the kernel. These device nodes are essential for the system to function properly. The udev demon takes care of creating and removing all these device nodes in /dev/.

Devices in the /dev directory and subdirectories are either character (providing only a serial stream of input/output) or block (accessible randomly). Character devices include mouse, keyboard, modem while block devices include hard disk, floppy drive etc. If you have GNOME or KDE installed in your system, devices such as external drives or cds are automatically detected when connected (e.g via usb) or inserted (e.g via CD or DVD drive) and a popup window displaying the contents is automatically displayed. Files in the /dev directory are essential for the system to function properly. Examples of common files in the /dev include:

/dev/hda - the master device on primary IDE channel.
/dev/hdb - the slave device on primary IDE channel.
/dev/tty0 - first virtual console.
/dev/tty1 - second virtual console.
/dev/sda - first device on primary SCSI or SATA channel.
/dev/lp0 - first parallel port.

3)The /etc/ Directory

The /etc/ directory is reserved for configuration files that are local to the machine. No binaries are to be placed in /etc/. Any binaries that were once located in /etc/ should be placed into /sbin/ or /bin/.

Examples of directories in /etc are the X11/ and skel/:

/etc
|- X11/
|- skel/

The /etc/X11/ directory is for X Window System configuration files, such as xorg.conf. The /etc/skel/ directory is for "skeleton" user files, which are used to populate a home directory when a user is first created. Applications also store their configuration files in this directory and may reference them when they are executed.

4) The /lib/ Directory

The /lib/ directory should contain only those libraries needed to execute the binaries in /bin/ and /sbin/. These shared library images are particularly important for booting the system and executing commands within the root file system.

5)The /media/ Directory

The /media/ directory contains subdirectories used as mount points for removeable media such as usb storage media, DVDs, CD-ROMs, and Zip disks.

6)The /mnt/ Directory

The /mnt/ directory is reserved for temporarily mounted file systems, such as NFS file system mounts. For all removeable media, please use the /media/ directory. Automatically detected removeable media will be mounted in the /media directory.

7)The /opt/ Directory

The /opt/ directory provides storage for most application software packages.

A package placing files in the /opt/ directory creates a directory bearing the same name as the package. This directory, in turn, holds files that otherwise would be scattered throughout the file system, giving the system administrator an easy way to determine the role of each file within a particular package.

For example, if sample is the name of a particular software package located within the /opt/ directory, then all of its files are placed in directories inside the /opt/sample/ directory, such as /opt/sample/bin/ for binaries and /opt/sample/man/ for manual pages.

Packages that encompass many different sub-packages, data files, extra fonts, clipart etc are also located in the /opt/ directory, giving that large package a way to organize itself. In this way, our sample package may have different tools that each go in their own sub-directories, such as /opt/sample/tool1/ and /opt/sample/tool2/, each of which can have their own bin/, man/, and other similar directories.

8)The /proc/ Directory

The /proc/ directory contains special files that either extract information from or send information to the kernel. Examples include system memory, cpu information, hardware configuration etc.

Due to the great variety of data available within /proc/ and the many ways this directory can be used to communicate with the kernel, an entire chapter has been devoted to the subject. For more information, refer to Chapter 3, The proc File System.

9)The /sbin/ Directory

The /sbin/ directory stores executables used by the root user. The executables in /sbin/ are used at boot time, for system administration and to perform system recovery operations. Of this directory, the FHS says:

/sbin contains binaries essential for booting, restoring, recovering, and/or repairing the system in addition to the binaries in /bin. Programs executed after /usr/ is known to be mounted (when there are no problems) are generally placed into /usr/sbin. Locally-installed system administration programs should be placed into /usr/local/sbin.

At a minimum, the following programs should be in /sbin/:

arp, clock,
halt, init,
fsck.*, grub,
ifconfig, mingetty,
mkfs.*, mkswap,
reboot, route,
shutdown, swapoff,
swapon

Network Monitoring-Nagios

2008-08-05T14:36:00.001+05:30

What Is This?

Nagios® is a system and network monitoring application. It watches hosts and services that you specify,
alerting you when things go bad and when they get better.
Nagios was originally designed to run under Linux, although it should work under most other unices as
well.

Some of the many features of Nagios include:

Monitoring of network services (SMTP, POP3, HTTP, NNTP, PING, etc.)
Monitoring of host resources (processor load, disk usage, etc.)
Simple plugin design that allows users to easily develop their own service checks
Parallelized service checks
Ability to define network host hierarchy using "parent" hosts, allowing detection of and distinction
between hosts that are down and those that are unreachable
Contact notifications when service or host problems occur and get resolved (via email, pager, or
user-defined method)
Ability to define event handlers to be run during service or host events for proactive problem
resolution
Automatic log file rotation
Support for implementing redundant monitoring hosts
Optional web interface for viewing current network status, notification and problem history, log
file, etc.

Real world Ruby

2008-08-05T07:43:00.007+05:30

I am working on Ruby language since last few months. I really wondered, this is so beautyful language to work with, so what could be various usages of this great language? I Googled a bit for this and found many fascinating facts. I thought like sharing this information with you. Many people use Ruby in their daily jobs, others as hobby. But there are many other useful and important areas where Ruby is being used.

Simulations
NASA Langley Research Center uses Ruby to conduct simulations.

A research group in Motorola uses Ruby to script a simulator, to generate scenarios as well as to post process the data.

3D Modelling
Google SketchUp is a 3D modelling application which uses Ruby for its macro scripting API.

Business
Toranto Rehab uses a RubyWebDialogs based application to manage and track on-call and on-site support for IT help desk and IT operations teams.

Robotics
At MORPHA project, Ruby was used to implement reactive control part for the Siemens service robot.

Networking
Open Domain Server uses Ruby to allow people using dynamic DNS clients to update their IP configuration in real time so that it can be mapped to static domains.

Telephony
Ruby is being used within Lucent on a 3G wireless telephony product.

System Administration
Ruby was used to write the central data collection portion of Level 3 communications Unix capacity and planning system that gathers performance statistics from over 1700 Unix (Solaris and Linux) servers scattered around the globe.

Web Applications
Basecamp, a web-based project management application developed by 37signals is programmed entirely in Ruby.

43 things allows you to keep a list of goals and share it with the world. It was developed entirely in Ruby.

A List Apart, a magazine for people who make websites that has been around since 1997, has recently been revamped and uses a custom application built with Ruby on Rails.

Blue Sequence, a sophisticated mission-critical application which forms part of Toyota Motor Manufacturing's own "Sequence-in-time" production process, has recently been selected as finalist in this years British Computers (BCS) Information Management Awards.

What is Raid Level and LVM in Linux...

2008-07-26T19:47:00.001+05:30

What is RAID and LVM

RAID is usually defined as Redundant Array of Inexpensive disks. It is normally used to spread data among several physical hard drives with enough redundancy that should any drive fail the data will still be intact. Once created a RAID array appears to be one device which can be used pretty much like a regular partition. There are several kinds of RAID but I will only refer to the two most common here.

The first is RAID-1 which is also known as mirroring. With RAID-1 it's basically done with two essentially identical drives, each with a complete set of data. The second, the one I will mostly refer to in this guide is RAID-5 which is set up using three or more drives with the data spread in a way that any one drive failing will not result in data loss. The Red Hat website has a great overview of the RAID Levels.

There is one limitation with Linux Software RAID that a /boot partition can only reside on a RAID-1 array.

Linux supports both several hardware RAID devices but also software RAID which allows you to use any IDE or SCSI drives as the physical devices. In all cases I'll refer to software RAID.

LVM stands for Logical Volume Manager and is a way of grouping drives and/or partition in a way where instead of dealing with hard and fast physical partitions the data is managed in a virtual basis where the virtual partitions can be resized. The Red Hat website has a great overview of the Logical Volume Manager.

There is one limitation that a LVM cannot be used for the /boot.

C++: void pointers

2008-06-19T08:50:00.002+05:30

The keyword 'void' can be used to define a pointer to a generic term. In C++, special care has to be taken to handle the assignment of void pointers to other pointer types. Following code shows the same:

void *p;
char *s;
p = s;
s = p;

Here, the second assignment would flag an error indicating a type mismatch. While you can assign a pointer of any type to a void pointer, the reverse is not true unless you specifically typecast it as shown below:

s = (char*) p;

C++: Anonymous unions and enums

2008-06-19T08:20:00.003+05:30

An anonymous union does not have a union name (tag) and its elements can be accessed directly without using a union variable.
For example,

union {
int i;
char ch[2];
};

Both i and array ch[] share the same memory locations and can be accessed directly simply by saying

i = 10;
ch[0] = 'A';

Simply omitting the union name in declaration does not make the anonymous union. For an union to qualify as an anonymous union, the declaration must not declare a variable of the union type.

Similarly, we can build anonymous enums as shown below:

enum {first, second, third};
int position = second;

The stream I/O classes define several anonymous enumerated types.

Do you know?

2008-05-19T11:21:00.001+05:30

If you want to find out which interrupt caused your application to terminate, use following formula to find this out.

Interrupt Number = Return Code - 128

where,
Return Code is value returned by your application on exit.

Cheers!

Send an Email to Undisclosed Recipients from Gmail

2008-04-02T10:08:00.001+05:30

Whenever you want to send mail to a mass of people, you generally include all the email IDs in the TO: field of your email client. So, when a recipient receives this mail, he/she can see who all are the other recipients. But what if you do not wish to disclose recipients email addresses? Here is a trick to keep recipients' addresses undisclosed. I have used Gmail to test this trick, but it works with all other email clients.

To address a message in Gmail so that it goes to "undisclosed recipients" but arrives in all the real recipient's inboxes:

1. Click Compose Mail to start a new message.

2. Type your own email address OR "Undisclosed Recipients <your email address>" (without double-quotes) in the To: field.

3. Click Add Bcc.

4. Type the email addresses of all the intended recipients in the Bcc: field. Make sure you separate addresses by comma. If you write to same group of recipients frequently, you can make a mailing list.

5. Now type the subject and message, and finally click Send button.

That's all !!

CAPTCHA

2008-04-01T11:19:00.001+05:30

The word CAPTCHA stands for "Completely Automated Public Turing test to tell Computers and Humans Apart".
CAPTCHA is a type of challenge-response test used in computing to determine whether a user is being imitated by a computer. The process involves one computer (a server) asking a user to complete a simple test which the computer is able to generate and grade. Because other computers are unable to solve the CAPTCHA, any user entering a correct solution is presumed to be human. A common type of CAPTCHA requires that the user type the letters displayed in a distorted image, sometimes with the addition of an obscured sequence of letters or digits that appears on the screen.

A CAPTCHA is sometimes described as a reverse Turing test, because it is administered by a machine and targeted to a human, in contrast to the standard Turing test that is typically administered by a human and targeted to a machine.

Currently, reCAPTCHA is recommended as the official CAPTCHA implementation by the original CAPTCHA creators.

Applications:
CAPTCHAs are used to prevent automated software from performing actions which degrade the quality of service of a given system, whether due to abuse or resource expenditure. Although CAPTCHAs are most often deployed as a response to encroachment by commercial interests, the notion that they exist to stop only spammers is mistaken. CAPTCHAs can be deployed to protect systems vulnerable to e-mail spam, such as the webmail services of Gmail (there is also a claim that the Gmail CAPTCHA has been compromised), Hotmail, and Yahoo!. CAPTCHAs have also found active use in stopping automated posting to blogs, forums and wikis, whether as a result of commercial promotion, or harassment and vandalism. CAPTCHAs also serve an important function in rate limiting, as automated usage of a service might be desirable until such usage is done in excess, and to the detriment of human users. In such a case, a CAPTCHA can enforce automated usage policies as set by the administrator when certain usage metrics exceed a given threshold. The article rating systems used by many news web sites are another example of an online facility vulnerable to manipulation by automated software.

SAP:-Introduction..

2008-03-25T14:33:00.001+05:30

What is SAP?
SAP is the leading Enterprise Information and Management Package worldwide. Use of this package makes it possible to track and manage, in real-time, sales, production, finance accounting and human resources in an enterprise.

SAP the company was founded in Germany in 1972 by five ex-IBM engineers. In case you’re ever asked, SAP stands for Systeme, Andwendungen, Produkte in der Datenverarbeitung which - translated to English - means Systems, Applications, Products in Data Processing. So now you know! Being incorporated in Germany, the full name of the parent company is SAP AG. It is located in Walldorf, Germany which is close to the beautiful town of Heidelberg. SAP has subsidiaries in over 50 countries around the world from Argentina to Venezuela (and pretty much everything in between). SAP America (with responsibility for North America, South America and Australia - go figure!) is located just outside Philadelphia, PA.

SAP Application Modules
SAP has several layers. The Basis System is the heart of the data operations and should be not evident to higher level or managerial users. Other customizing and implementation tools exist also. The heart of the system from a manager's viewpoint are the application modules. These modules may not all be implemented in a typical company but they are all related and are listed below:

*

FI Financial Accounting--designed for automated management and external reporting of general ledger, accounts receivable, accounts payable and other sub-ledger accounts with a user defined chart of accounts. As entries are made relating to sales production and payments journal entries are automatically posted. This connection means that the "books" are designed to reflect the real situation.
*

CO Controlling--represents the company's flow of cost and revenue. It is a management instrument for organizational decisions. It too is automatically updated as events occur.
*

AM Asset Management--designed to manage and supervise individual aspects of fixed assets including purchase and sale of assets, depreciation and investment management.
*

PS Project System--is designed to support the planning, control and monitoring of long-term, highly complex projects with defined goals.
*

WF Workflow--links the integrated SAP application modules with cross-application technologies, tools and services
*

IS Industry Solutions--combine the SAP application modules and additional industry-specific functionality. Special techniques have been developed for industries such as banking, oil and gas, pharmaceuticals, etc.
*

HR Human Resources--is a complete integrated system for supporting the planning and control of personnel activities.
*

PM Plant Maintenance--In a complex manufacturing process maintenance means more than sweeping the floors. Equipment must be services and rebuilt. These tasks affect the production plans.
*

MM Materials Management--supports the procurement and inventory functions occurring in day-to-day business operations such as purchasing, inventory management, reorder point processing, etc.
*

QM Quality Management--is a quality control and information system supporting quality planning, inspection, and control for manufacturing and procurement.
*

PP Production Planning--is used to plan and control the manufacturing activities of a company. This module includes; bills of material, routings, work centers, sales and operations planning, master production scheduling, material requirements planning, shop floor control, production orders, product costing, etc.
*

SD Sales and Distribution--helps to optimize all the tasks and activities carried out in sales, delivery and billing. Key elements are; pre-sales support, inquiry processing, quotation processing, sales order processing, delivery processing, billing and sales information system
.

KolourPaint: More than a Microsoft Paint clone

2008-03-25T13:17:00.003+05:30

Just as Microsoft Paint is included with every Windows installation, so KolourPaint has been part of the kdegraphics package since KDE 3.3. This simple raster graphics editor works well not only in KDE, but also in Xfce, GNOME, and Fluxbox.

Although it started out as a clone of Microsoft Paint, KolourPaint has grown to include more features than its proprietary inspiration. KolourPaint provides tools for image manipulation and icon editing as well as the typical "fingerpainting" that Paint is well known for. KolourPaint's and Paint's interfaces are nearly identical, but hidden behind a simple interface are several advanced features that make it a great graphics editor.

With the release of KDE 4, KolourPaint 4.0 brings some new features to the table, such as a configurable palette, some heavily refactored code, and new image effects that make photo editing a breeze.

Comparisons to Paint
KolourPaint has all the tools that Paint provides, such as the Brush, Color Eraser, Color Picker, Connected Lines/Polyline, Pen, Polygon, Rectangle, and Text to name a few. It also incorporates single-key shortcuts for all its tools to allow for better productivity. One of the handiest improvements over Paint is the number of levels of undo and redo, which, depending on memory usage, may be anywhere from 10 to 500 levels of history. Selections are also fully undo- and redo-able. KolourPaint includes support for freehand resizing and arbitrary rotation angles, and provides a choice between opaque and transparent selections.

[Click to enlarge] Click to enlargeClick to enlarge KolourPaint's Zoomed Thumbnail mode is an excellent addition to the Paint-like genre. It displays a thumbnail version of an image that works similar to an additional view in the GIMP. You can draw on the thumbnail, erase upon it, and use any selection tool on it. The selection tool needs a little more work in the thumbnail ability, as you can't see what contents you are selecting until you let go of the mouse button. You can resize the Zoomed Thumbnail by resizing its window.

KolourPaint provides Color Similarity, which allows you to fill regions in dithered images and photos. In addition to the standard Paint colors, KolourPaint lets you use other color sets (such as the Oxygen Icons in the latest version), or to create your own.

Unlike Paint, KolourPaint can save in every file format that KImageIO can provide; PNG, ICO, and PCX are supported, with the ability preview the images before you load them.

One of the biggest differences between KolourPaint and Paint is the support for transparency. Every KolourPaint tools lets you draw transparent icons and logos on a checkerboard background. This ability helps KolourPaint act as an icon editor too. By filling the workspace with the transparent "color" and resizing the image to a common icon size, you can whip up some catchy icons in a matter of minutes.

Photo editing

KolourPaint is also a useful photo editing application. Like the GIMP, it allows you to autocrop (remove internal borders) and adjust brightness, contrast, and gamma. Operations you can perform include clear, flatten, emboss, flip, and invert with the choice of channels. You can also resize and rotate, reduce colors, reduce images to greyscale, and smooth scale, soften, and sharpen images.

Effects allow you to change the appearance of the image, such as making an image look like it was painted on canvas. You can access effects that appear under the Image menu from the dialog window, as well as those that don't. The Balance effect, which changes the brightness, contrast, and the gamma of an image, is curiously placed in a new dialog window under Image -> More Effects, rather than as an entry in the Image menu. Almost all effects have an easy slider bar that let you change their values, and a thumbnail of the image that automatically updates when you apply an effect.

Anyone looking to fine-tune their graphic skills, or who would like to become more comfortable with KolourPaint, can peruse the KolourPaint Manual. To obtain further support, users can join the KolourPaint Support mailing list.

KolourPaint lacks a few of Paint's features. Some features currently under development include paletted image editing, selectable text, screen depth independence, and image acquisition from a scanner or a camera.

Still, with many of the features that the GIMP contains, and all but a few of Microsoft Paint's features, KolourPaint provides a simple user interface to manipulate photos and create raster graphics. By blending a completed user interface, stable image effects, and innovative features, KolourPaint's developers have put it one step ahead of other Linux Paint clones. As a graphics application, KolourPaint is powerful enough to make even the GIMP respect it.

What is Hacking?

2008-03-25T12:31:00.000+05:30

Username: system
Password: manager
Welcome to ABL Computer Research Lab. You have five new messages.
$

That is how easy it was to hack into a computer network. The most prominent definition of hacking is the act of gaining access without legal authorization to a computer or computer network. A hacker first attacks an easy target, and then uses it to hide his or her traces for launching attacks at more secure sites. The goal of an attack is to gain complete control of the system (so you can edit, delete, install, or execute any file in any user’s directory), often by gaining access to a "super-user" account. This will allow both maximum access and the ability to hide your presence.

Often attacks are based on software bugs that a hacker can use to give himself or herself super-user status. The example above was used by West German hacker "Pengo" who exploited the fact that many systems came with default usernames and passwords which some buyers neglected to change. He succeeded by persistence.

Also one can get a copy of the password file (which stores usernames and encrypted passwords and is often publicly accessible) and either do a brute-force attack trying all possible combinations, or encrypt a dictionary and compare the results to see if anyone chose a password that is a dictionary word. Another method of hacking is to email someone a program that either automatically runs, or that runs when they click on an attachment. This can install a program that will give you control of their computer. L0pht Heavy Industry’s Back Orifice 2000 (a crude parody of Microsoft’s Office 2000) allows someone to have nearly complete control (running programs, deleting files, viewing the screen, logging typed keys, etc.) over the target computer without being noticed. One complicated method, known as IP spoofing, is to get one computer to pretend that it is another one which is trusted by the target system, thus gaining the access privileges of the latter.

Early hackers needed to be very knowledgeable so that they were able to identify bugs themselves (a task requiring extensive knowledge about the operating system, and reading complex manuals) and often write their own programs to exploit them. They had to keep track of the leading developments in the field (latest bugs, latest patches, latest bugs in the patches, etc.). Later hackers were able to increasingly rely upon the hacking community to identify bugs and write programs that could be adapted for their specific purpose. For instance, famed hacker Kevin Mitnick used a trojan horse written by the West German Chaos Gang to gain access to hundreds of systems. As another example, it does not take much intelligence to download a copy of Back Orifice 2000 from www.bo2k.com and send a copy of the client as an attachment disguised as a game or cute program, to an unsuspecting person. In fact, Back Orifice has been downloaded over 300,000 times (Deane 1999) and received substantial computer media coverage. In Pengo’s case it is often more a matter of dedication and trying well-known recipes until one finds a place that has not fixed the bugs, than genius.

The growing number of inexperienced hackers (deridingly called "lamers" or "crackers"), due to the growth first in BBSes and then in the Internet, helps explain the antagonism between the older generation that did more of the problem-solving for themselves and the new generation that can get a quick start by running hacker programs without understanding how they work. The reaction of the older generation is to shun the newbies, thus ignoring those who might show talent as well as those who are in it just to copy tactics.

VMware Server (for Windows and Linux systems)

2008-03-24T14:35:00.002+05:30

VMware Server (for Windows and Linux systems)

Use Multiple Operating Systems Concurrently on the Same PC

VMware Workstation 6 makes it simple to create and run multiple virtual machines on your desktop or laptop computer. You can convert an existing physical PC into a VMware virtual machine, or create a new virtual machine from scratch. Each virtual machine represents a complete PC, including the processor, memory, network connections and peripheral ports.

VMware Workstation lets you use your virtual machines to run Windows, Linux and a host of other operating systems side-by-side on the same computer. You can switch between operating systems instantly with a click of a mouse, share files between virtual machines with drag-and-drop functionality and access all the peripheral devices you rely on.

Take Snapshots & Videos of your Virtual Machines

With Workstation, you can take a “snapshot” that preserves the state of a virtual machine so you can return to it at any time. Snapshots are useful when you need to revert your virtual machine to a prior, stable system state. Workstation displays thumbnails of all your snapshots on a single screen, making it easy for you to track and revert to a previously saved snapshot.

You can even use Workstation 6 to record and play video files that capture all changes to a virtual machine over a period of time. This function is exclusive to VMware Workstation and is incredibly useful for software debugging, Help Desk forensics, sales demonstrations and training.

Run an Entire Multi-tier System on a Single Host Computer

Run multi-tier enterprise applications on a single piece of hardware by managing network-connected virtual machines with the Teams feature of Workstation 6. Teams let you create virtual network environments that include client, server and database virtual machines.

With Workstation Teams, you can turn an entire multi-tier environment on and off with a single click of the mouse button. Workstation displays live thumbnails of all connected virtual machines, enabling you to easily identify and switch between the virtual machines associated with a team.

Broadest Host & Guest Operating System Support
* Runs on both Windows and Linux host operating systems and supports most desktop and server editions of Microsoft Windows, Linux, Solaris x86, Netware, and FreeBSD as guest operating systems
* Supports both 32-bit and 64-bit host and guest operating systems
* Supports two-way Virtual SMP™ – Assign one or two processors to virtual machines
* Experimental support for VMI 3.0 enabled paravirtualized Linux kernels

Click Here To Download VmWare..

How to study SQL Online...

2008-03-24T14:18:00.003+05:30

Hello Guys...........

Click on following link and study SQL.You can also fire Query there,no need of having Oracle installed on your machine.

Click Here TO Study SQL Online.

Crontab : Scheduling Tasks

2008-03-24T14:03:00.002+05:30

Crontab permits to schedule tasks on your computer. For example you can program a safeguard every month on the 13th, or administrative tasks such as booting tasks (checking emails, log off network stations , etc...).
Keywords: @annually , @daily , @hourly , @midnight , @monthly , @reboot , @weekly , @yearly , command , cron.allow , cron.deny , crontab , Scheduling tasks , user .

We first notice that crontab stands out the at utility. Indeed crontab permits to schedule tasks, that is to say repetitive tasks, whereas at only executes one task.

Allow a user to use crontab

My username is nadir. First you have to allow nadir to use the crontab command. We log in as root and we check if the /etc/cron.allow file exists. If it exists, add the user nadir in the file, if it does not exist create it and add the user nadir.
root@ipower:~# nano -w /etc/cron.allow

or write (vi,gedit, nedit, kwrite, etc...) and fill out the file accordingly.

From now on, the nadir user is allowed to use crontab. So it is possible to specify who are the (users) allowed to use crontab and those who are not allowed. To do that, we use the /etc/cron.allow and /etc/cron.deny files.

If the /etc/cron.allow file exists, only the users mentioned will have the right to use the cron command.

If the /etc/cron.allow file does not exist, it is the /etc/cron.deny file which is taken into account: the mentioned users will not have the right to use the cron command.

If neither of the two files exists, only the super user (root) will have the right to use the cron command.

Note: an empty /etc/cron.deny file means that all the users can use the cron commande.

Use of crontab

Once the nadir user is allowed, this one is able to use crontab. Using the crontab -l option, list the current tasks:
nadir@ipower:~$ crontab -l no crontab for nadir

We can clearly see that no task is defined. Well, it is now or never!

First of all, create a task file
nadir@ipower:~$ crontab -e

Now you had to fill out it. The syntax is: m h dom mon dow command
- m forminute between 0 and 59
- h for hour between 0 and 11
- dom for day of month between 1 and 31
- mon for month between 1 and 12
- dow for day of week between 0 and 7, sunday is represented by 0 or 7, monday by 1, etc ...
- command to execute the command.

Now, take an interest in some special characters (metacharacters) :
- *, if one of the m h dom mon dow fields owns the * character, then it indicates evey minute or evey hour or every day or every day of the month or every month or every day of the week, it depends on which field is placed *.
- / permits to specify a repetition.
- - permits to define a range.
- , permits to specify several values.

Some examples:

*/5 * * * * command to execute a command every 5 minutes.

0 22 * * 1-5 command to execute a command every day, monday to friday, at 10 p.m.

17 19 1,15 * * command means the first and the fifteenth day of the month at 19h17 (7.17 p.m.)

23 0-16/2 * * * command means every 2 hours at the twenty-third minute, between midnight and

How to use java in OPEN Source....

2008-02-04T13:42:00.000+05:30

Java Open Source Workflow
Enhydra Shark
The Enhydra Shark project delivers an Open Source Java workflow server with a difference. It is an extendable and embeddable Java open source workflow engine framework including a standard implementation completely based on WfMC specifications using XPDL (without any proprietary extensions !) as its native workflow process definition format and the WfMC "ToolAgents" API for serverside execution of system activities. Every single component (persistence layer, transaction manager, scripting engines, process repository,...) can be used with its standard implementation or extended/replaced by project specific modules.

Enhydra JaWE
Enhydra JaWE (Java Workflow Editor) is the first open source graphical Java workflow process editor fully according to WfMC specifications supporting XPDL as its native file format. It can be used to edit / view every XPDL file which conforms to WfMC XPDL specifications , does NOT use any proprietary XPDL extensions and is available in English, German, French and Serbian language already. Advanced features like the consistency validation and guided property editor dialogs for all XPDL objects make it really easy to create valid XPDL files. The representation of workflow participants as "swimlanes" in the editor graphics gives a comprehensive overview of process responsibilities.

Home
Enhydra.org Sucess Stories

Versicherungs-Vergleich.at is using Enhydra Application Server and Enhydra Shark Workflow to develop its new base software for online insurance comparisons.

etenso GmbH in Germany uses Enhydra Server to implement a knowledge and information management product and wins the ObjectWeb Award ! Read more...

AKBANK in Turkey uses Enhydra Shark and Enhydra JaWE with support from Together for approval mechanisms in retail banking. Read more...

OpenUSS uses Enhydra Enterprise to serve thousands of students worldwide.

OfBiz uses Enhydra Shark as their internal workflow engine with thousands of users worldwide.

GrECo International AG succesfully deployed Enhydra Snapper in their LAN, integrated the fulltext indexing / search and the document previewer into their insurance broking application "BroSys" and GrECo users search in about 2.2 million documents in fragments of seconds !

Java Open Source Workflow

Enhydra Shark
The Enhydra Shark project delivers an Open Source Java workflow server with a difference. It is an extendable and embeddable Java open source workflow engine framework including a standard implementation completely based on WfMC specifications using XPDL (without any proprietary extensions !) as its native workflow process definition format and the WfMC "ToolAgents" API for serverside execution of system activities. Every single component (persistence layer, transaction manager, scripting engines, process repository,...) can be used with its standard implementation or extended/replaced by project specific modules.

Enhydra JaWE
Enhydra JaWE (Java Workflow Editor) is the first open source graphical Java workflow process editor fully according to WfMC specifications supporting XPDL as its native file format. It can be used to edit / view every XPDL file which conforms to WfMC XPDL specifications , does NOT use any proprietary XPDL extensions and is available in English, German, French and Serbian language already. Advanced features like the consistency validation and guided property editor dialogs for all XPDL objects make it really easy to create valid XPDL files. The representation of workflow participants as "swimlanes" in the editor graphics gives a comprehensive overview of process responsibilities.

Java Open Source Application Server

Enhydra Server
Enhydra Server is an Open Source Java application and webservice server including standard Apache Tomcat (or alternatively Jetty) and Apache Axis with a very big difference ! While the servlet API is used to support presentation logic, the platform contains just about all enterprise level services to build extreme high volume web sites in an n-tier architecture. The architecture is designed for perfomance and in tests we showed incredible performance numbers ! Many Enhydra servers are powering the Web today, some catering to millions of transactions a day. One of the most talked about features of Enhydra is its Enhydra XMLC technology - an object-oriented standards based replacement for JSP that completely separates the designer and developer. In addition, Enhydra includes a relational-to-object mapping tool (Enhydra DODS), Enhydra Workflow (Shark and JaWE), clustering web server extensions for Apache, IIS and IPlanet and much more. Check it out, you won't be sorry! :-)

Enhydra Enterprise
This is the effort to bring the advantages of the Open Source Java application server Enhydra to existing J2EE container implementations. Open Source J2EE containers like JOnAS and JBoss are supported already ! And Apache Geronimo will also be packaged as an alternative to EAF addons for commercial J2EE servers like IBM Websphere, BEA Weblogic, Oracle and Sun J2EE servers.

Home
Enhydra.org Sucess Stories

Versicherungs-Vergleich.at is using Enhydra Application Server and Enhydra Shark Workflow to develop its new base software for online insurance comparisons.

etenso GmbH in Germany uses Enhydra Server to implement a knowledge and information management product and wins the ObjectWeb Award ! Read more...

AKBANK in Turkey uses Enhydra Shark and Enhydra JaWE with support from Together for approval mechanisms in retail banking. Read more...

OpenUSS uses Enhydra Enterprise to serve thousands of students worldwide.

OfBiz uses Enhydra Shark as their internal workflow engine with thousands of users worldwide.

GrECo International AG succesfully deployed Enhydra Snapper in their LAN, integrated the fulltext indexing / search and the document previewer into their insurance broking application "BroSys" and GrECo users search in about 2.2 million documents in fragments of seconds !

Java Open Source Workflow

Enhydra Shark
The Enhydra Shark project delivers an Open Source Java workflow server with a difference. It is an extendable and embeddable Java open source workflow engine framework including a standard implementation completely based on WfMC specifications using XPDL (without any proprietary extensions !) as its native workflow process definition format and the WfMC "ToolAgents" API for serverside execution of system activities. Every single component (persistence layer, transaction manager, scripting engines, process repository,...) can be used with its standard implementation or extended/replaced by project specific modules.

Enhydra JaWE
Enhydra JaWE (Java Workflow Editor) is the first open source graphical Java workflow process editor fully according to WfMC specifications supporting XPDL as its native file format. It can be used to edit / view every XPDL file which conforms to WfMC XPDL specifications , does NOT use any proprietary XPDL extensions and is available in English, German, French and Serbian language already. Advanced features like the consistency validation and guided property editor dialogs for all XPDL objects make it really easy to create valid XPDL files. The representation of workflow participants as "swimlanes" in the editor graphics gives a comprehensive overview of process responsibilities.

Java Open Source Application Server

Enhydra Server
Enhydra Server is an Open Source Java application and webservice server including standard Apache Tomcat (or alternatively Jetty) and Apache Axis with a very big difference ! While the servlet API is used to support presentation logic, the platform contains just about all enterprise level services to build extreme high volume web sites in an n-tier architecture. The architecture is designed for perfomance and in tests we showed incredible performance numbers ! Many Enhydra servers are powering the Web today, some catering to millions of transactions a day. One of the most talked about features of Enhydra is its Enhydra XMLC technology - an object-oriented standards based replacement for JSP that completely separates the designer and developer. In addition, Enhydra includes a relational-to-object mapping tool (Enhydra DODS), Enhydra Workflow (Shark and JaWE), clustering web server extensions for Apache, IIS and IPlanet and much more. Check it out, you won't be sorry! :-)

Enhydra Enterprise
This is the effort to bring the advantages of the Open Source Java application server Enhydra to existing J2EE container implementations. Open Source J2EE containers like JOnAS and JBoss are supported already ! And Apache Geronimo will also be packaged as an alternative to EAF addons for commercial J2EE servers like IBM Websphere, BEA Weblogic, Oracle and Sun J2EE servers.

Java Open Source Tools and Technologies

Enhydra XMLC
Enhydra XMLC is the presentation technology that supports the needs of designers, developers and architects alike, delivering what JSP cannot - strict separation of markup and logic in a true object view of dynamic presentations. XMLC is now fully portable to Tomcat 4, 5 as well as JBoss, BEA, Enhydra and other Web Container implementations. Enhydra XMLC is included in Enhydra Server and Enhydra Enterprise. Several Enhydra Demos also use XMLC !

Enhydra DODS
Enhydra DODS (Data Object Design Studio) is an open source relational-object-mapping tool with a difference. Based on XML data model descriptions the SQL DDL, sophisticated Java code and documentation (HTML, pdf, XMI) is generated automatically using a generator GUI, by Ant tasks or from within the Eclipse IDE. The generated Java code provides a lot of possibilities for runtime optimization (DO LRU caching, Query LRU caching, cache initialization, lazyloading,...).

Enhydra Director
Enhydra Director is a collection of open source web-server plugins to provide loadbalancing, clustering and unified connection methods for different web-servers on different platforms. It supports several popular Web servers and operating systems, including Apache (on Linux/Unix and Windows), Netscape Enterprise Server (on Linux/UNIX and Windows), and Microsoft Internet Information Server. Director also supports several applications servers: Tomcat (v5.xx and v5.5x), Jetty, JOnAS, JBoss and Enhydra Server.

Enhydra Octopus
Enhydra Octopus is a Java-based Extraction, Transformation, and Loading (ETL) tool. It may connect to any JDBC data sources and perform transformations defined in an XML file.

Enhydra Application Framework
Enhydra application framework EAF is a portable set of APIs making development of typical web applications a lot easier but still keeping portability to the application server of your choice by using plug-ins to adopt the EAF API's to the specific environment.

Enhydra Kelp
The Enhydra Kelp project is focused on creating tools that make it easy to get the most out of other Enhydra technologies such as XMLC, Octopus and DODS. Kelp includes command line tools, application wizards and Eclipse IDE plug-ins.

Enhydra Oyster
Enhydra Oyster is an Open Source Java library for SMIME signing and encryption of E-Mails using different key strengths and algorithms. It is developed with suport and testing for major E-Mail clients.

i-Phone:-Introduction

2008-01-03T15:49:00.000+05:30

iPhone is a revolutionary new mobile phone that allows you to make a call by simply tapping a name or number in your address book, a favorites list, or a call log. It also automatically syncs all your contacts from a PC, Mac, or Internet service. And it lets you select and listen to voicemail messages in whatever order you want — just like email.

iPhone uses OS X, the world’s most advanced operating system. Which means you have access to the best-ever software on a handheld device, including rich HTML email, full-featured web browsing, and favorite applications including Address Book and Calendar. iPhone is also fully multi-tasking, so you can read a web page while downloading your email in the background. This software completely redefines what you can do with a mobile phone.

iPhone uses quad-band GSM, the global standard for wireless communications. It also supports AT&T’s EDGE network, 802.11b/g Wi-Fi, and Bluetooth 2.0 with EDR, which links to Apple’s compact Bluetooth headset. When you move around, iPhone automatically switches between EDGE and Wi-Fi to provide the fastest data connection possible. To set up your own Wi-Fi network, check out the AirPort Extreme Base Station.

Enterprise JavaBeans (EJB) :Introduction

2007-12-10T15:24:00.000+05:30

Enterprise JavaBeans (EJB) technology is the server-side component architecture for Java Platform, Enterprise Edition (Java EE). EJB technology enables rapid and simplified development of distributed, transactional, secure and portable applications based on Java technology.

The EJB specification intends to provide a standard way to implement the back-end 'business' code typically found in enterprise applications (as opposed to 'front-end' user-interface code). Such code was frequently found to reproduce the same types of problems, and it was found that solutions to these problems are often repeatedly re-implemented by programmers. Enterprise Java Beans were intended to handle such common concerns as persistence, transactional integrity, and security in a standard way, leaving programmers free to concentrate on the particular problem at hand.

EJB types
Stateful Session Beans are distributed objects having state: that is, they keep track of which calling program they are dealing with throughout a session. For example, checking out in a web store might be handled by a stateful session bean, which would use its state to keep track of where the customer is in the checkout process. On the other hand, sending an e-mail to customer support might be handled by a stateless bean, since this is a one-off operation and not part of a multi-step process. Stateful session beans' state may be persisted, but access to the bean instance is limited to only one client. Stateless Session Beans are distributed objects that do not have state associated with them thus allowing concurrent access to the bean. The contents of instance variables are not guaranteed to be preserved across method calls. The lack of overhead to maintain a conversation with the calling program makes them less resource-intensive than stateful beans.

Message Driven Beans were introduced in the EJB 2.0 specification. which is supported by Java 2 Platform, Enterprise Edition 1.3 or higher. The message bean represents the integration of JMS (Java Message Service) with EJB to create an entirely new type of bean designed to handle asynchronous JMS messages. Message Driven Beans are distributed objects that behave asynchronously. That is, they handle operations that do not require an immediate response. For example, a user of a website clicking on a "keep me informed of future updates" box may trigger a call to a Message Driven Bean to add the user to a list in the company's database. (This call is asynchronous because the user does not need to wait to be informed of its success or failure.) These beans subscribe to JMS (Java Message Service) message queues or message topics. They were added in the EJB 2.0 specification to allow event-driven processing inside EJB Container. Unlike other types of beans, MDB does not have a client view (Remote/Home interfaces), i.e. clients can not look-up an MDB instance. It just listens for any incoming message on a JMS queue (or topic) and processes them automatically.

Previous versions of EJB also used a type of bean known as an Entity Bean. These were distributed objects having persistent state. Beans in which their container managed the persistent state were said to be using Container-Managed Persistence (CMP), whereas beans that managed their own state were said to be using Bean-Managed Persistence (BMP). Entity Beans were replaced by the Java Persistence API in EJB 3.0, though as of 2007, CMP 2.x style Entity beans are still available for backward compatibility.

Other types of Enterprise Beans have been proposed. For instance, Enterprise Media Beans (JSR 86) address the integration of multimedia objects in Java EE applications.

The Year 2038 Bug

2007-12-03T00:47:00.000+05:30

It's barely 8 years since we had the millenium bug so don't say you didn't get enough warning! A lot of systems in the world may have date rollover troubles in a fraction over 30 years time. The millenium bug (more accurately known as the Two Digit Century Rollover Bug) was caused by using 2 digits instead of 4 for the year. So Christmas 2007 falls on 12/25/07. Of course when 1999 rolled over to 2000 then the first day of the new century became 01/01/00 and this could have had serious consequences had all the old systems not been sorted out in advance. This problem will also happen again in 2099, 2199 etc if anyone is silly enough to keep using two digit year dates.

But the Unix bug will occur in 2038. That's because the date system started in 1970 and uses a time_t (signed int) to hold the number of seconds. The highest value is 2147483648-1 which is 24855.13 days. Add that to Jan 1 1970 and you get Jan 19 2038! So sometime early on that morning of that date, any software using a signed int for a date will rollover to Jan 1 1970! So how you are going to cope up with this problem dudes....!!!

Storage :1TB Hard Disk Drive

2007-11-04T12:53:00.000+05:30

Recently Both Major companies Hitachi and Seagate have launched the disk drives of 1TB(1024 GB) which is major milestone in storage world.
In INDIAN markets currently Hitechi launched the drives of 1 tb.
“Growing volumes of songs, movies, personal videos, pictures and games stored on our PCs highlights a ready market for higher capacity HDDs in India,”.

“At 133 gigabits per square inch, the Hitachi 1TB hard drive crams much more data per square inch than any other HDD available in the market today. Quieter acoustics, lower heat dissipation levels and much faster read/write speeds, makes this family of Hitachi HDDs a must have for all PC users,” he added further.

The 3.5inch drive belongs to the 7200 RPM family of Hitachi 1TB SATA hard disk drives. These storage units can be used for business, commercial, gaming, media centre PCs and also in external storage devices. The new drive is equipped with reliable perpendicular magnetic recoding technology, robust 3GB SATA interface and enhanced Rotational Vibration Safeguard (RVS) technology.

Besides, the 1TB drive ensures the fast data transfer rates, low power consumption and advanced shock protection. Hitachi 1TB SATA hard disk comes along with a 5-year warranty.

System, designed to sustain performance in densely packed multi-drive systems.

Seagate Barracuda 7200.11 hard drive consumes 13W of power in comparison to Hitachi’s 1-TB hard drive which draws about 13.6W. In addition, the Seagate new 1TB hard drive has just 4 platters which results in cool operating temperatures and low-power consumption helping longer hard disk life with less chances for wear and tear.

Seagate claims that the Barracuda 7200.11 1TB hard drive unit is a newly designed product optimised for demanding business-critical and nearline enterprise storage environments including: networked and tiered storage solutions, reference/compliance storage, disc-to-disc backup and restore, archiving solutions, rich media content storage and collaboration.

Company also claims that the new Barracuda 7200.11 hard drive also boosts reliability with an unrecoverable error rate that is 10 times better than desktop class drives and a 1.2 million hour Mean Time Between Failure at full 24 x 7 data

Read More:
Seagate 1 TB HDD
and Hitechi 1 TB HDD

Also Its Interesting: hitachi

Software Testing:Key Concepts

2007-11-01T19:03:00.000+05:30

Taxonomy
There is a plethora of testing methods and testing techniques, serving multiple purposes in different life cycle phases. Classified by purpose, software testing can be divided into: correctness testing, performance testing, reliability testing and security testing. Classified by life-cycle phase, software testing can be classified into the following categories: requirements phase testing, design phase testing, program phase testing, evaluating test results, installation phase testing, acceptance testing and maintenance testing. By scope, software testing can be categorized as follows: unit testing, component testing, integration testing, and system testing
Correctness testing
Correctness is the minimum requirement of software, the essential purpose of testing. Correctness testing will need some type of oracle, to tell the right behavior from the wrong one. The tester may or may not know the inside details of the software module under test, e.g. control flow, data flow, etc. Therefore, either a white-box point of view or black-box point of view can be taken in testing software. We must note that the black-box and white-box ideas are not limited in correctness testing only.

Black-box testing
The black-box approach is a testing method in which test data are derived from the specified functional requirements without regard to the final program structure. [Perry90] It is also termed data-driven, input/output driven [Myers79], or requirements-based [Hetzel88] testing. Because only the functionality of the software module is of concern, black-box testing also mainly refers to functional testing -- a testing method emphasized on executing the functions and examination of their input and output data. [Howden87] The tester treats the software under test as a black box -- only the inputs, outputs and specification are visible, and the functionality is determined by observing the outputs to corresponding inputs. In testing, various inputs are exercised and the outputs are compared against specification to validate the correctness. All test cases are derived from the specification. No implementation details of the code are considered.

It is obvious that the more we have covered in the input space, the more problems we will find and therefore we will be more confident about the quality of the software. Ideally we would be tempted to exhaustively test the input space. But as stated above, exhaustively testing the combinations of valid inputs will be impossible for most of the programs, let alone considering invalid inputs, timing, sequence, and resource variables. Combinatorial explosion is the major roadblock in functional testing. To make things worse, we can never be sure whether the specification is either correct or complete. Due to limitations of the language used in the specifications (usually natural language), ambiguity is often inevitable. Even if we use some type of formal or restricted language, we may still fail to write down all the possible cases in the specification. Sometimes, the specification itself becomes an intractable problem: it is not possible to specify precisely every situation that can be encountered using limited words. And people can seldom specify clearly what they want -- they usually can tell whether a prototype is, or is not, what they want after they have been finished. Specification problems contributes approximately 30 percent of all bugs in software. [Beizer95]

The research in black-box testing mainly focuses on how to maximize the effectiveness of testing with minimum cost, usually the number of test cases. It is not possible to exhaust the input space, but it is possible to exhaustively test a subset of the input space. Partitioning is one of the common techniques. If we have partitioned the input space and assume all the input values in a partition is equivalent, then we only need to test one representative value in each partition to sufficiently cover the whole input space. Domain testing [Beizer95] partitions the input domain into regions, and consider the input values in each domain an equivalent class. Domains can be exhaustively tested and covered by selecting a representative value(s) in each domain. Boundary values are of special interest. Experience shows that test cases that explore boundary conditions have a higher payoff than test cases that do not. Boundary value analysis [Myers79] requires one or more boundary values selected as representative test cases. The difficulties with domain testing are that incorrect domain definitions in the specification can not be efficiently discovered.

Good partitioning requires knowledge of the software structure. A good testing plan will not only contain black-box testing, but also white-box approaches, and combinations of the two.

White-box testing
Contrary to black-box testing, software is viewed as a white-box, or glass-box in white-box testing, as the structure and flow of the software under test are visible to the tester. Testing plans are made according to the details of the software implementation, such as programming language, logic, and styles. Test cases are derived from the program structure. White-box testing is also called glass-box testing, logic-driven testing [Myers79] or design-based testing [Hetzel88].

There are many techniques available in white-box testing, because the problem of intractability is eased by specific knowledge and attention on the structure of the software under test. The intention of exhausting some aspect of the software is still strong in white-box testing, and some degree of exhaustion can be achieved, such as executing each line of code at least once (statement coverage), traverse every branch statements (branch coverage), or cover all the possible combinations of true and false condition predicates (Multiple condition coverage). [Parrington89]

Control-flow testing, loop testing, and data-flow testing, all maps the corresponding flow structure of the software into a directed graph. Test cases are carefully selected based on the criterion that all the nodes or paths are covered or traversed at least once. By doing so we may discover unnecessary "dead" code -- code that is of no use, or never get executed at all, which can not be discovered by functional testing.

In mutation testing, the original program code is perturbed and many mutated programs are created, each contains one fault. Each faulty version of the program is called a mutant. Test data are selected based on the effectiveness of failing the mutants. The more mutants a test case can kill, the better the test case is considered. The problem with mutation testing is that it is too computationally expensive to use. The boundary between black-box approach and white-box approach is not clear-cut. Many testing strategies mentioned above, may not be safely classified into black-box testing or white-box testing. It is also true for transaction-flow testing, syntax testing, finite-state testing, and many other testing strategies not discussed in this text. One reason is that all the above techniques will need some knowledge of the specification of the software under test. Another reason is that the idea of specification itself is broad -- it may contain any requirement including the structure, programming language, and programming style as part of the specification content.

We may be reluctant to consider random testing as a testing technique. The test case selection is simple and straightforward: they are randomly chosen. Study in [Duran84] indicates that random testing is more cost effective for many programs. Some very subtle errors can be discovered with low cost. And it is also not inferior in coverage than other carefully designed testing techniques. One can also obtain reliability estimate using random testing results based on operational profiles. Effectively combining random testing with other testing techniques may yield more powerful and cost-effective testing strategies.

Performance testing
Not all software systems have specifications on performance explicitly. But every system will have implicit performance requirements. The software should not take infinite time or infinite resource to execute. "Performance bugs" sometimes are used to refer to those design problems in software that cause the system performance to degrade.

Performance has always been a great concern and a driving force of computer evolution. Performance evaluation of a software system usually includes: resource usage, throughput, stimulus-response time and queue lengths detailing the average or maximum number of tasks waiting to be serviced by selected resources. Typical resources that need to be considered include network bandwidth requirements, CPU cycles, disk space, disk access operations, and memory usage [Smith90]. The goal of performance testing can be performance bottleneck identification, performance comparison and evaluation, etc. The typical method of doing performance testing is using a benchmark -- a program, workload or trace designed to be representative of the typical system usage. [Vokolos98]

Reliability testing
Software reliability refers to the probability of failure-free operation of a system. It is related to many aspects of software, including the testing process. Directly estimating software reliability by quantifying its related factors can be difficult. Testing is an effective sampling method to measure software reliability. Guided by the operational profile, software testing (usually black-box testing) can be used to obtain failure data, and an estimation model can be further used to analyze the data to estimate the present reliability and predict future reliability. Therefore, based on the estimation, the developers can decide whether to release the software, and the users can decide whether to adopt and use the software. Risk of using software can also be assessed based on reliability information. [Hamlet94] advocates that the primary goal of testing should be to measure the dependability of tested software.

There is agreement on the intuitive meaning of dependable software: it does not fail in unexpected or catastrophic ways. [Hamlet94] Robustness testing and stress testing are variances of reliability testing based on this simple criterion.

The robustness of a software component is the degree to which it can function correctly in the presence of exceptional inputs or stressful environmental conditions. [IEEE90] Robustness testing differs with correctness testing in the sense that the functional correctness of the software is not of concern. It only watches for robustness problems such as machine crashes, process hangs or abnormal termination. The oracle is relatively simple, therefore robustness testing can be made more portable and scalable than correctness testing. This research has drawn more and more interests recently, most of which uses commercial operating systems as their target, such as the work in [Koopman97] [Kropp98] [Ghosh98] [Devale99] [Koopman99].

Stress testing, or load testing, is often used to test the whole system rather than the software alone. In such tests the software or system are exercised with or beyond the specified limits. Typical stress includes resource exhaustion, bursts of activities, and sustained high loads.

Security testing
Software quality, reliability and security are tightly coupled. Flaws in software can be exploited by intruders to open security holes. With the development of the Internet, software security problems are becoming even more severe.

Many critical software applications and services have integrated security measures against malicious attacks. The purpose of security testing of these systems include identifying and removing software flaws that may potentially lead to security violations, and validating the effectiveness of security measures. Simulated security attacks can be performed to find vulnerabilities.

IT News:Democratising IT

2007-10-31T14:32:00.000+05:30

A New Model For PC Penetration
INDIA has emerged as a global leader in the advance of information technology. Yet the country faces a fundamental challenge — building on its successes by enabling greater access to technology for its people. This will drive expanded economic growth and opportunity. Less than 3% of Indians own a personal computer — compared to nearly 8% of Chinese, almost 14% of Brazilians and more than 15% of Russians. Despite the very low penetration of computers in India, the impact has been profound. India is home to three of the world’s 10 biggest IT firms — Tata, Infosys, and Wipro, and already generates nearly $40 billion in revenues from its IT software and services sector. Nasscom forecasts this figure to grow by nearly 27% next year. It must be recognised that the benefits of broader IT use and deeper Internet access are substantial, and will be a catalyst for — not a result of — economic growth and modernisation. India is already benefiting from e-governance initiatives that deliver real-time tallying of results of the world’s largest elections and from technology-driven distance learning that brings the world’s educational resources to students without regard to location or economic background. But cost has been a major roadblock for broader technology adoption in India. Reducing taxes and tariffs is essential to facilitating broader access to technology and driving growth in the technology sectors. Global hardware exports are 43% of Chinese exports versus only 2.3% for India. India is clearly missing out on a big opportunity. If it doesn’t act soon, investments will go further into China and emerging countries such as Vietnam, instead of India.
Consider also that, in India, a typical desktop computer costs 44% of the average Indian’s annual wage. Brazil’s experience in supporting technology adoption is particularly instructive. Since reducing taxes on computer purchases two years ago, the PC market tripled, and more than two million families bought their first PC, making Brazil the world’s fourth-largest PC market. What was more important was the multiplier effect this had on the economy. Thousands of IT industry jobs were created and government revenue from the IT sector increased by 50%. But cost isn’t the only barrier. IT complexity will also threaten access to technology while increasing its cost and environmental impact. We are all members of what we at Dell call the ReGeneration — a new global movement concerned with the regeneration of not just our businesses but also our planet. Environmental protection efforts are improving, as reflected in the Nobel Prize jointly awarded to former US vice-president Al Gore and the Intergovernmental Panel on Climate Change headed by Rajendra Pachauri. And technology is an important part of these efforts. The future will bring even more benefits.
By 2020 microprocessors will run one thousand times as many computations per second as they do today. That will mean enormous gains in productivity and efficiency, giving people unimaginable power to access, organise, and transform information. Indian citizens will more fully benefit from this progress as government and industry leaders strengthen their cooperation. This will help create the conditions in which IT can flourish and reach all people, businesses, and institutions across the country. India plays a pivotal role in global IT. Technology users in the western world benefit every day from the work of bright, talented Indian employees and their constant innovation. But more than serving as the world’s software writer or back office, India is harnessing the productivity, efficiency, and innovation benefits of IT as a foundation for global economic competitiveness. I see industry working, with great commitment, with India’s government to build on this progress, and to help further democratize access to technology, so that more Indian citizens enjoy even more of technology’s benefits with an ever-decreasing impact on our environment. That is our shared responsibility. By harnessing these forces — the democratization and simplification of technology, we can make a positive impact not just on our economies, but also our planet.

(Michael Dell)

Software Testing:Introduction

2007-10-28T11:00:00.000+05:30

Introduction
Software Testing is the process of executing a program or system with the intent of finding errors. [Myers79] Or, it involves any activity aimed at evaluating an attribute or capability of a program or system and determining that it meets its required results. [Hetzel88] Software is not unlike other physical processes where inputs are received and outputs are produced. Where software differs is in the manner in which it fails. Most physical systems fail in a fixed (and reasonably small) set of ways. By contrast, software can fail in many bizarre ways. Detecting all of the different failure modes for software is generally infeasible. [Rstcorp]

Unlike most physical systems, most of the defects in software are design errors, not manufacturing defects. Software does not suffer from corrosion, wear-and-tear -- generally it will not change until upgrades, or until obsolescence. So once the software is shipped, the design defects -- or bugs -- will be buried in and remain latent until activation.

Software bugs will almost always exist in any software module with moderate size: not because programmers are careless or irresponsible, but because the complexity of software is generally intractable -- and humans have only limited ability to manage complexity. It is also true that for any complex systems, design defects can never be completely ruled out.

Discovering the design defects in software, is equally difficult, for the same reason of complexity. Because software and any digital systems are not continuous, testing boundary values are not sufficient to guarantee correctness. All the possible values need to be tested and verified, but complete testing is infeasible. Exhaustively testing a simple program to add only two integer inputs of 32-bits (yielding 2^64 distinct test cases) would take hundreds of years, even if tests were performed at a rate of thousands per second. Obviously, for a realistic software module, the complexity can be far beyond the example mentioned here. If inputs from the real world are involved, the problem will get worse, because timing and unpredictable environmental effects and human interactions are all possible input parameters under consideration.

A further complication has to do with the dynamic nature of programs. If a failure occurs during preliminary testing and the code is changed, the software may now work for a test case that it didn't work for previously. But its behavior on pre-error test cases that it passed before can no longer be guaranteed. To account for this possibility, testing should be restarted. The expense of doing this is often prohibitive. [Rstcorp]

An interesting analogy parallels the difficulty in software testing with the pesticide, known as the Pesticide Paradox [Beizer90]: Every method you use to prevent or find bugs leaves a residue of subtler bugs against which those methods are ineffectual. But this alone will not guarantee to make the software better, because the Complexity Barrier [Beizer90] principle states: Software complexity(and therefore that of bugs) grows to the limits of our ability to manage that complexity. By eliminating the (previous) easy bugs you allowed another escalation of features and complexity, but his time you have subtler bugs to face, just to retain the reliability you had before. Society seems to be unwilling to limit complexity because we all want that extra bell, whistle, and feature interaction. Thus, our users always push us to the complexity barrier and how close we can approach that barrier is largely determined by the strength of the techniques we can wield against ever more complex and subtle bugs. [Beizer90]

Regardless of the limitations, testing is an integral part in software development. It is broadly deployed in every phase in the software development cycle. Typically, more than 50% percent of the development time is spent in testing. Testing is usually performed for the following purposes:
To improve quality.
As computers and software are used in critical applications, the outcome of a bug can be severe. Bugs can cause huge losses. Bugs in critical systems have caused airplane crashes, allowed space shuttle missions to go awry, halted trading on the stock market, and worse. Bugs can kill. Bugs can cause disasters. The so-called year 2000 (Y2K) bug has given birth to a cottage industry of consultants and programming tools dedicated to making sure the modern world doesn't come to a screeching halt on the first day of the next century. [Bugs] In a computerized embedded world, the quality and reliability of software is a matter of life and death.

Quality means the conformance to the specified design requirement. Being correct, the minimum requirement of quality, means performing as required under specified circumstances. Debugging, a narrow view of software testing, is performed heavily to find out design defects by the programmer. The imperfection of human nature makes it almost impossible to make a moderately complex program correct the first time. Finding the problems and get them fixed [Kaner93], is the purpose of debugging in programming phase.

For Verification & Validation (V&V)
Just as topic Verification and Validation indicated, another important purpose of testing is verification and validation (V&V). Testing can serve as metrics. It is heavily used as a tool in the V&V process. Testers can make claims based on interpretations of the testing results, which either the product works under certain situations, or it does not work. We can also compare the quality among different products under the same specification, based on results from the same test.

We can not test quality directly, but we can test related factors to make quality visible. Quality has three sets of factors -- functionality, engineering, and adaptability. These three sets of factors can be thought of as dimensions in the software quality space. Each dimension may be broken down into its component factors and considerations at successively lower levels of detail. Table 1 illustrates some of the most frequently cited quality considerations.
Good testing provides measures for all relevant factors. The importance of any particular factor varies from application to application. Any system where human lives are at stake must place extreme emphasis on reliability and integrity. In the typical business system usability and maintainability are the key factors, while for a one-time scientific program neither may be significant. Our testing, to be fully effective, must be geared to measuring each relevant factor and thus forcing quality to become tangible and visible. [Hetzel88]

Tests with the purpose of validating the product works are named clean tests, or positive tests. The drawbacks are that it can only validate that the software works for the specified test cases. A finite number of tests can not validate that the software works for all situations. On the contrary, only one failed test is sufficient enough to show that the software does not work. Dirty tests, or negative tests, refers to the tests aiming at breaking the software, or showing that it does not work. A piece of software must have sufficient exception handling capabilities to survive a significant level of dirty tests.

A testable design is a design that can be easily validated, falsified and maintained. Because testing is a rigorous effort and requires significant time and cost, design for testability is also an important design rule for software development.

For reliability estimation
Software reliability has important relations with many aspects of software, including the structure, and the amount of testing it has been subjected to. Based on an operational profile (an estimate of the relative frequency of use of various inputs to the program [Lyu95]), testing can serve as a statistical sampling method to gain failure data for reliability estimation.

Software testing is not mature. It still remains an art, because we still cannot make it a science. We are still using the same testing techniques invented 20-30 years ago, some of which are crafted methods or heuristics rather than good engineering methods. Software testing can be costly, but not testing software is even more expensive, especially in places that human lives are at stake. Solving the software-testing problem is no easier than solving the Turing halting problem. We can never be sure that a piece of software is correct. We can never be sure that the specifications are correct. No verification system can verify every correct program. We can never be certain that a verification system is correct either.

IT News:Cognizant pips Infy to acquire marketRx for $135 m

2007-10-20T13:39:00.000+05:30

Cognizant pips Infy to acquire marketRx for $135 m
COGNIZANT Technology Solutions, an IT and BPO services company, said it will pay $135 million in cash to acquire New Jersey-based marketRx, a provider of analytics and related software services to life sciences companies. It’s the biggest acquisition made by Cognizant so far, and among the biggest in high-end business process outsourcing space recently.
In a deal structured on Thursday night, Cognizant is believed to have pipped IT services giant Infosys Technologies in bagging the deal. Earlier, ET reported that a host of suitors, including biggies Infosys and Wipro, had evinced interest in acquiring marketRx, one of the largest, independent offshore KPO businesses. Two investment banks, Mumbai-based Avendus and US-based William Blair, advised marketRx in sealing the deal.
This is the second high-profile dealmaking in the KPO space, after WNS snapped up Bangalore headquartered Marketics for $65 million earlier this year. Sources said while Infosys’ valuation of the marketRx was higher, Cognizant offered upfront cash pay out. It is believed that Infy’s offer had a substantial chunk of earnings payout, which essentially means a combination of upfront money and the remaining to be based on future performance.
The Nasdaq-listed Cognizant with predominant operations in India said the acquisition would help strengthen its analytics unit and offer more services to life sciences industry. The deal is expected to close in fourth quarter of 2007, and would be funded from its cash reserves. marketRx with per employee revenue of about $100,000 is projected to report revenues of over $40 million in 2007. It has 430 people, with 260 in Gurgaon, 160 in the US (four locations), and 10 in London.
Cognizant is expected to cross 55,000 people by end of this year and with revenue guidance of $2.11 billion in 2007. It’s manpower addition this year is expected to be over 16,000, 40 times the strength of marketRx. Cognizant president R Chandrasekaran said: “It is a ‘tuck-under’ acquisition that is consistent with our acquisition strategy of selectively acquiring businesses that complement or enhance our business model and value to our customers.
Cognizant president and CEO Francisco D’- Souza said: “This acquisition expands our capabilities in the analytics segment and broadens our service offerings for the life sciences industry while providing strong synergies with our existing business intelligence/data warehousing and CRM (customer relationship management) services.”
marketRx has a proven global delivery model for analytics, deep domain knowledge and proprietary analytics software platform, he said. “We expect to leverage these assets to establish a pre-eminent position in the fast-growing analytics market both in life sciences and other industries,” Mr D’Souza said in a statement.
marketRx president & CEO Jaswinder (Jassi) Chadha said: “The combination of our market leading position in the life sciences analytics segment and Cognizant’s strengths as a top global services player will allow us to expand our relationships with our life sciences clients by providing them with a broader range of outsourced services, and conversely enables us to extend our capabilities to other vertical markets.”

Mainframe:Mainframe Server Software Architectures

2007-10-19T09:58:00.000+05:30

Mainframe Server Software Architectures

Purpose and OriginSince 1994 mainframes have been combined with distributed architectures to provide massive storage and to improve system security, flexibility, scalability, and reusability in the client/server design. In a mainframe server software architecture, mainframes are integrated as servers and data warehouses in a client/server environment. Additionally, mainframes still excel at simple transaction-oriented data processing to automate repetitive business tasks such as accounts receivable, accounts payable, general ledger, credit account management, and payroll. Siwolp and Edelstein provide details on mainframe server software architectures see [Siwolp 95, Edelstein 94].

Technical DetailWhile client/server systems are suited for rapid application deployment and distributed processing, mainframes are efficient at online transactional processing, mass storage, centralized software distribution, and data warehousing [Data 96]. Data warehousing is information (usually in summary form) extracted from an operational database by data mining (drilling down into the information through a series of related queries). The purpose of data warehousing and data mining is to provide executive decision makers with data analysis information (such as trends and correlated results) to make and improve business decisions.
a mainframe in a three tier client/server architecture. The combination of mainframe horsepower as a server in a client/server distributed architecture results in a very effective and efficient system. Mainframe vendors are now providing standard communications and programming interfaces that make it easy to integrate mainframes as servers in a client/server architecture. Using mainframes as servers in a client/server distributed architecture provides a more modular system design, and provides the benefits of the client/server technology.

Using mainframes as servers in a client/server architecture also enables the distribution of workload between major data centers and provides disaster protection and recovery by backing up large volumes of data at disparate locations. The current model favors "thin" clients (contains primarily user interface services) with very powerful servers that do most of the extensive application and data processing, such as in a two tier architecture. In a three tier client/server architecture, process management (business rule execution) could be off-loaded to another server.

Usage ConsiderationsMainframes are preferred for big batch jobs and storing massive amounts of vital data. They are mainly used in the banking industry, public utility systems, and for information services. Mainframes also have tools for monitoring performance of the entire system, including networks and applications not available today on UNIX servers [Siwolp 95].
New mainframes are providing parallel systems (unlike older bipolar machines) and use complementary metal-oxide semiconductor (CMOS) microprocessors, rather than emitter-coupler logic (ECL) processors. Because CMOS processors are packed more densely than ECL microprocessors, mainframes can be built much smaller and are not so power-hungry. They can also be cooled with air instead of water [Siwolp 95].

While it appeared in the early 1990s that mainframes were being replaced by client/server architectures, they are making a comeback. Some mainframe vendors have seen as much as a 66% jump in mainframe shipments in 1995 due to the new mainframe server software architecture [Siwolp 95].

Given the cost of a mainframe compared to other servers, UNIX workstations and personal computers (PCs), it is not likely that mainframes would replace all other servers in a distributed two or three tier client/server architecture.

MaturityMainframe technology has been well known for decades. The new improved models have been fielded since 1994. The new mainframe server software architecture provides the distributed client/server design with massive storage and improved security capability. New technologies of data warehousing and data mining data allow extraction of information from the operational mainframe server's massive storage to provide businesses with timely data to improve overall business effectiveness. For example, stores such as Wal-Mart found that by placing certain products in close proximity within the store, both products sold at higher rates than when not collocated.1

Costs and LimitationsBy themselves, mainframes are not appropriate mechanisms to support graphical user interfaces. Nor can they easily accommodate increases in the number of user applications or rapidly changing user needs [Edelstein 94].

AlternativesUsing a client/server architecture without a mainframe server is a possible alternative. When requirements for high volume (greater than 50 gigabit), batch type processing, security, and mass storage are minimal, three tier or two tier architectures without a mainframe server may be viable alternatives. Other possible alternatives to using mainframes in a client/server distributed environment are using parallel processing software architecture or using a database machine.

Complementary TechnologiesA complementary technology to mainframe server software architectures is open systems . This is because movement in the industry towards interoperable heterogeneous software programs and operating systems will continue to increase reuse of mainframe technology and provide potentially new applications for mainframe capabilities.

How To: Burn a CD using Windows XP

2007-10-14T09:23:00.000+05:30

You can burn a CD using Windows XP. No special CD-burning software required. All it needs is a CD-R or CD-RW disk, a machine running Windows XP and a CD-RW disk drive.

Step 1
Insert a blank CD-R or CD-RW disk into the CD-RW drive. A pop-up dialog box should appear after Windows loads the CD. (No pop-up dialog box? Open "My Computer" from your desktop and double-click on your CD-RW drive icon.)

Step 2
Double-click the option, "Open writable CD folder using Windows Explorer." You will see the files that are currently on the CD in your CD-RW drive. If you inserted a blank CD, you will see nothing.

Step 3
Click on the "Start" menu, and then "My Computer." (No "My Computer" on your start menu? It is likely you have the Windows Classic Start Menu enabled, and you will have to double-click "My Computer" on the desktop instead.) Navigate to the files that you wish to burn onto the CD.

Step 4
Single-click on the first file you wish to burn. Hold down the "Control" key and continue to single-click on other desired files until you have selected them all. Let go of the "Control" key. All your files should remain selected and appear blue. Right-click on any file and choose "Copy."

Step 5
Go back to the open window that displays the contents of your CD drive. Right-click in the white space and choose "Paste." The pasted icons will appear washed out, and they will have little black arrows on them indicating your next step.

Step 6
Choose "Write these files to CD" on the left-hand menu bar under "CD Writing Tasks." A wizard will start. First, name your CD. You can use up to 16 characters. After typing a name, click "Next." This will start the burning process. When the CD is finished burning, the CD will eject itself.

Step 7
Follow the remaining wizard prompts. It will ask if you want to burn the same files to another CD. If so, click "Yes, write these files to another CD." If not, click "Finish." You're done.

Tips & Warnings
Make sure to test your newly burned CD—try to open a few files to ensure that the process was done correctly.

Networking:Client/Server

2007-10-12T14:05:00.000+05:30

Client/Server Software Architectures--An Overview

Purpose and Origin
The term client/server was first used in the 1980s in reference to personal computers (PCs) on a network. The actual client/server model started gaining acceptance in the late 1980s. The client/server software architecture is a versatile, message-based and modular infrastructure that is intended to improve usability, flexibility, interoperability, and scalability as compared to centralized, mainframe, time sharing computing.

A client is defined as a requester of services and a server is defined as the provider of services. A single machine can be both a client and a server depending on the software configuration. For details on client/server software architectures see Schussel and Edelstein [Schussel 96, Edelstein 94].

This technology description provides a summary of some common client/server architectures and, for completeness, also summarizes mainframe and file sharing architectures. Detailed descriptions for many of the individual architectures are provided elsewhere in the document.

Technical Detail
Mainframe architecture (not a client/server architecture). With mainframe software architectures all intelligence is within the central host computer. Users interact with the host through a terminal that captures keystrokes and sends that information to the host. Mainframe software architectures are not tied to a hardware platform. User interaction can be done using PCs and UNIX workstations. A limitation of mainframe software architectures is that they do not easily support graphical user interfaces (see Graphical User Interface Builders) or access to multiple databases from geographically dispersed sites. In the last few years, mainframes have found a new use as a server in distributed client/server architectures (see Client/Server Software Architectures) [Edelstein 94].

File sharing architecture (not a client/server architecture). The original PC networks were based on file sharing architectures, where the server downloads files from the shared location to the desktop environment. The requested user job is then run (including logic and data) in the desktop environment. File sharing architectures work if shared usage is low, update contention is low, and the volume of data to be transferred is low. In the 1990s, PC LAN (local area network) computing changed because the capacity of the file sharing was strained as the number of online user grew (it can only satisfy about 12 users simultaneously) and graphical user interfaces (GUIs) became popular (making mainframe and terminal displays appear out of date). PCs are now being used in client/server architectures [Schussel 96, Edelstein 94].

Client/server architecture. As a result of the limitations of file sharing architectures, the client/server architecture emerged. This approach introduced a database server to replace the file server. Using a relational database management system (DBMS), user queries could be answered directly. The client/server architecture reduced network traffic by providing a query response rather than total file transfer. It improves multi-user updating through a GUI front end to a shared database. In client/server architectures, Remote Procedure Calls (RPCs) or standard query language (SQL) statements are typically used to communicate between the client and server [Schussel 96, Edelstein 94].

The remainder of this write-up provides examples of client/server architectures.

Two tier architectures. With two tier client/server architectures (see Two Tier Software Architectures), the user system interface is usually located in the user's desktop environment and the database management services are usually in a server that is a more powerful machine that services many clients. Processing management is split between the user system interface environment and the database management server environment. The database management server provides stored procedures and triggers. There are a number of software vendors that provide tools to simplify development of applications for the two tier client/server architecture [Schussel 96, Edelstein 94].

The two tier client/server architecture is a good solution for distributed computing when work groups are defined as a dozen to 100 people interacting on a LAN simultaneously. It does have a number of limitations. When the number of users exceeds 100, performance begins to deteriorate. This limitation is a result of the server maintaining a connection via "keep-alive" messages with each client, even when no work is being done. A second limitation of the two tier architecture is that implementation of processing management services using vendor proprietary database procedures restricts flexibility and choice of DBMS for applications. Finally, current implementations of the two tier architecture provide limited flexibility in moving (repartitioning) program functionality from one server to another without manually regenerating procedural code. [Schussel 96, Edelstein 94].

Three tier architectures. The three tier architecture (see Three Tier Software Architectures) (also referred to as the multi-tier architecture) emerged to overcome the limitations of the two tier architecture. In the three tier architecture, a middle tier was added between the user system interface client environment and the database management server environment. There are a variety of ways of implementing this middle tier, such as transaction processing monitors, message servers, or application servers. The middle tier can perform queuing, application execution, and database staging. For example, if the middle tier provides queuing, the client can deliver its request to the middle layer and disengage because the middle tier will access the data and return the answer to the client. In addition the middle layer adds scheduling and prioritization for work in progress. The three tier client/server architecture has been shown to improve performance for groups with a large number of users (in the thousands) and improves flexibility when compared to the two tier approach. Flexibility in partitioning can be a simple as "dragging and dropping" application code modules onto different computers in some three tier architectures. A limitation with three tier architectures is that the development environment is reportedly more difficult to use than the visually-oriented development of two tier applications [Schussel 96, Edelstein 94]. Recently, mainframes have found a new use as servers in three tier architectures (see Mainframe Server Software Architectures).

Three tier architecture with transaction processing monitor technology. The most basic type of three tier architecture has a middle layer consisting of Transaction Processing (TP) monitor technology (see Transaction Processing Monitor Technology). The TP monitor technology is a type of message queuing, transaction scheduling, and prioritization service where the client connects to the TP monitor (middle tier) instead of the database server. The transaction is accepted by the monitor, which queues it and then takes responsibility for managing it to completion, thus freeing up the client. When the capability is provided by third party middleware vendors it is referred to as "TP Heavy" because it can service thousands of users. When it is embedded in the DBMS (and could be considered a two tier architecture), it is referred to as "TP Lite" because experience has shown performance degradation when over 100 clients are connected. TP monitor technology also provides

* the ability to update multiple different DBMSs in a single transaction
* connectivity to a variety of data sources including flat files, non-relational DBMS, and the mainframe
* the ability to attach priorities to transactions
* robust security

Using a three tier client/server architecture with TP monitor technology results in an environment that is considerably more scalable than a two tier architecture with direct client to server connection. For systems with thousands of users, TP monitor technology (not embedded in the DBMS) has been reported as one of the most effective solutions. A limitation to TP monitor technology is that the implementation code is usually written in a lower level language (such as COBOL), and not yet widely available in the popular visual toolsets [Schussel 96].

Three tier with message server. Messaging is another way to implement three tier architectures. Messages are prioritized and processed asynchronously. Messages consist of headers that contain priority information, and the address and identification number. The message server connects to the relational DBMS and other data sources. The difference between TP monitor technology and message server is that the message server architecture focuses on intelligent messages, whereas the TP Monitor environment has the intelligence in the monitor, and treats transactions as dumb data packets. Messaging systems are good solutions for wireless infrastructures [Schussel 96].

Three tier with an application server. The three tier application server architecture allocates the main body of an application to run on a shared host rather than in the user system interface client environment. The application server does not drive the GUIs; rather it shares business logic, computations, and a data retrieval engine. Advantages are that with less software on the client there is less security to worry about, applications are more scalable, and support and installation costs are less on a single server than maintaining each on a desktop client [Schussel 96]. The application server design should be used when security, scalability, and cost are major considerations [Schussel 96].

Three tier with an ORB architecture. Currently industry is working on developing standards to improve interoperability and determine what the common Object Request Broker (ORB) will be. Developing client/server systems using technologies that support distributed objects holds great pomise, as these technologies support interoperability across languages and platforms, as well as enhancing maintainability and adaptability of the system. There are currently two prominent distributed object technologies:

* Common Object Request Broker Architecture (CORBA)
* COM/DCOM (see Component Object Model (COM), DCOM, and Related Capabilities).

Industry is working on standards to improve interoperability between CORBA and COM/DCOM. The Object Management Group (OMG) has developed a mapping between CORBA and COM/DCOM that is supported by several products [OMG 96].

Distributed/collaborative enterprise architecture. The distributed/collaborative enterprise architecture emerged in 1993 (see Distributed/Collaborative Enterprise Architectures). This software architecture is based on Object Request Broker (ORB) technology, but goes further than the Common Object Request Broker Architecture (CORBA) by using shared, reusable business models (not just objects) on an enterprise-wide scale. The benefit of this architectural approach is that standardized business object models and distributed object computing are combined to give an organization flexibility to improve effectiveness organizationally, operationally, and technologically. An enterprise is defined here as a system comprised of multiple business systems or subsystems. Distributed/collaborative enterprise architectures are limited by a lack of commercially-available object orientation analysis and design method tools that focus on applications [Shelton 93, Adler 95].

Usage Considerations
Client/server architectures are being used throughout industry and the military. They provide a versatile infrastructure that supports insertion of new technology more readily than earlier software designs.

Maturity
Client/server software architectures have been in use since the late 1980s. See individual technology descriptions for more detail.

Costs and Limitations
There a number of tradeoffs that must be made to select the appropriate client/server architecture. These include business strategic planning, and potential growth on the number of users, cost, and the homogeneity of the current and future computational environment.

Dependencies
If a distributed object approach is employed, then the CORBA and/or COM/DCOM technologies should be considered (see Common Object Request Broker Architecture and Component Object Model (COM), DCOM, and Related Capabilities).

Alternatives
Alternatives to client/server architectures would be mainframe or file sharing architectures.

Complementary Technologies
Complementary technologies for client/server architectures are computer-aided software engineering (CASE) tools because they facilitate client/server architectural development, and open systems (see COTS and Open Systems--An Overview) because they facilitate the development of architectures that improve scalability and flexibility.

IT News:Talent pool may raise biz for IT product cos

2007-10-11T15:28:00.000+05:30

Talent pool may raise biz for IT product cos

WITH India becoming the global IT services hub, leading product companies including Oracle, Sun Micro systems, IBM and Microsoft are sharpening their focus on the education sector to promote their technologies and bolster revenues. These companies are actively forging ties with educational and training institutes to develop a ready-touse talent pool. The partnerships could indirectly bring in more business, say analysts.
The programmers are designed to help companies position their products in the global marketplace. Availability of talent pool could be a differentiating factor in a closely-contested deal. In a multi-million dollar deal, when a client is selecting a product partner, they will look at market capabilities, mainly the number of professionals who have trained on the product technologies. “With more and more businesses outsourcing their services to India, it is important for major product development companies to create a large tech-savvy resource pool here,” said Gartner principal analyst Kamlesh Bhatia.
IBM, for instance, has imparted training on open standards-based technologies to more than 80,000 students across 745 colleges in India in 2006. “As part of IBM Academic Initiative, we offer workshops and certification programmes on various technologies. The aim is to develop strategic linkages with universities and colleges and to assist them in developing talent pool,” says IBM programme director Amol Mahamuni.
Microsoft India has also partnered with the Board for Information Technology Education Standards (BITES) in Karnataka to address the training needs of students in BITES member institutes.
TALENT CONTEST
IT cos are tying up with educational & training institutes to develop ready-to-use talent pool Availability of talent pool could be a differentiating factor in a closely-contested deal IBM has imparted training on open standards-based technologies to 80,000 students across 745 colleges in India

What is web content management system?

2007-10-11T09:21:00.000+05:30

Web content management systems are often used for storing, controlling, versioning, and publishing industry-specific documentation such as news articles, operators' manuals, technical manuals, sales guides, and marketing brochures. A content management system may support the following features:

* Import and creation of documents and multimedia material
* Identification of all key users and their content management roles
* The ability to assign roles and responsibilities to different content categories or types.
* Definition of the content workflow tasks, often coupled with event messaging so that content managers are alerted to changes in content.
* The ability to track and manage multiple versions of a single instance of content.
* The ability to publish the content to a repository to support access to the content. Increasingly, the repository is an inherent part of the system, and incorporates enterprise search and retrieval.
* Some content management systems allow the textual aspect of content to be separated to some extent from formatting. For example the CMS may automatically set default color, fonts, or layouts.

CMS: Content Management System

2007-10-10T09:11:00.000+05:30

A Content Management System (CMS) is a software system used for content management. Content management systems are deployed primarily for interactive use by a potentially large number of contributors.Other related forms of content management are listed below.

The content managed includes computer files, image media, audio files, electronic documents and web content. The idea behind a CMS is to make these files available inter-office, as well as over the web. A Content Management System would most often be used as an archive as well. Many companies use a CMS to store files in a non-proprietary form. Companies use a CMS to share files with ease, as most systems use server-based software, even further broadening file availability. As shown below, many Content Management Systems include a feature for Web Content, and some have a feature for a "workflow process."

"Work flow" is the idea of moving an electronic document along for either approval, or for adding content. Some Content Management Systems will easily facilitate this process with email notification, and automated routing. This is ideally a collaborative creation of documents. A CMS facilitates the organization, control, and publication of a large body of documents and other content, such as images and multimedia resources.

A web content management system is a content management system with additional features to ease the tasks required to publish web content to web sites.

PHP : What is smarty?

2007-10-09T13:47:00.000+05:30

Smarty is a web template system written in PHP. Smarty is primarily promoted as a tool for separation of concerns, which is a common design strategy for certain kinds of applications.

Smarty generates web content by the placement of special Smarty tags within a document. These tags are processed and substituted with other code.

Tags are directives for Smarty that are enclosed by template delimiters. These directives can be variables, denoted by a dollar sign ($), functions, or logical or control flow statements. Smarty allows PHP programmers to define functions that can be accessed using Smarty tags.

Smarty is intended to simplify compartmentalization, allowing the presentation of a web page to change separately from the back-end. Ideally, this eases the costs and efforts associated with software maintenance. Under successful application of this development strategy, designers are shielded from the back-end coding, and PHP programmers are shielded from the presentation coding.

Smarty supports several high-level template programming features, including:

* regular expressions
* Control flow statements, foreach, while
* if, elseif, else
* variable modifiers - For example {$variable|nl2br}
* user created functions
* mathematical evaluation within the template

along with other features. There are other template engines that also support these features. Smarty templates are often incorporated into existing PHP web applications to some extent. More often it is used where a web application or a website has a theme system built into it, where the templates can be changed from theme to theme.

Cellphone:Nokia's aeon "full surface screen" cellphone concept

2007-10-07T09:15:00.000+05:30

Nokia's Aeon: A concept phone that combines two touch-sensitive panels mounted on a fuel-cell power pack.keypad. Each of the panels are capable of being used independently. The touch screen displays all buttons that are virtual, so in one situation one panel could operate as the display, the other as the Nokia also establishes a new wireless standard with wibree, basically an upgraded bluetooth which would allow the Aeon to be a thin-client, farming out processing and storage.

The Aeon seems to be typical razer-thin candy bar form factor cell phone with no actual buttons. That can change into any kind of menu, button and keypad with a simple touch. The touch screen method brings up a ton of quirky problems like causing damage to the display with those pointy thumbs of yours.

The concept phone, dubbed Aeon, combines two touch-sensitive panels mounted on a fuel-cell power pack. The handset's connectivity and electronics are built into the panels to allow them to be used independently. When assembled, one panel would operate as the display, the other as the keypad. Since the buttons are entirely virtual, Aeon can flip instantly between a numeric pad for dialling, a text-entry pad for messaging and a media-player controller.

Nokia's vision of wearable technology users could wear the lightweight panels as a badge, or connected to a wrist strap. The most prominent design feature of aeon is a touchscreen that stretches over the full surface area of the phone, similar to benq siemens's black box concept phone .

read on nokia : click here to read more

full story:click here

SAP:SAP Customer Relationship Management:

2007-10-01T11:38:00.000+05:30

What is SAP?
SAP, started in 1972 by five former IBM employees in Mannheim, Germany, states that it is the world's largest inter-enterprise software company and the world's fourth-largest independent software supplier, overall.
The original name for SAP was German: Systeme, Anwendungen, Produkte, German for "Systems Applications and Products." The original SAP idea was to provide customers with the ability to interact with a common corporate database for a comprehensive range of applications. Gradually, the applications have been assembled and today many corporations, including IBM and Microsoft, are using SAP products to run their own businesses.
SAP applications, built around their latest R/3 system, provide the capability to manage financial, asset, and cost accounting, production operations and materials, personnel, plants, and archived documents. The R/3 system runs on a number of platforms including Windows 2000 and uses the client/server model. The latest version of R/3 includes a comprehensive Internet-enabled package.
SAP has recently recast its product offerings under a comprehensive Web interface, called mySAP.com, and added new e-business applications, including customer relationship management (CRM) and supply chain management (SCM).
As of January 2007, SAP, a publicly traded company, had over 38,4000 employees in over 50 countries, and more than 36,200 customers around the world. SAP is turning its attention to small- and-medium sized businesses (SMB). A recent R/3 version was provided for IBM's AS/400 platform.
SAP Customer Relationship Management:

Features & Functions

SAP Customer Relationship Management (SAP CRM) includes features and functions to support core business processes in the following areas:
Marketing – Analyze, plan, develop, and execute all marketing activities through all customer interaction points. This central marketing platform empowers marketers with complete business insights – enabling you to make intelligent business decisions and to drive end-to-end marketing processes. Quickly deploy marketing functionality in an on-demand model and transition to SAP CRM as business needs evolve.
Sales – Maintain focus on productive activity to acquire, grow, and retain profitable relationships with functionality for sales planning and forecasting, territories, accounts, contacts, activities, opportunities, quotations, orders, product configuration, pricing, billing, and contracts. Quickly deploy sales management functionality in an on-demand model and transition to SAP CRM as business needs evolve.
Service – Drive service revenue and profitability with support for service sales and marketing; service contract management; field service; e-service; workforce management; and channel service. Call centers, field service, and e-service provide various flexible delivery options. Quickly deploy service functionality in an on-demand model and transition to SAP CRM as business needs evolve.
Partner channel management – Attain a more profitable and loyal indirect channel by managing partner relationships and empowering channel partners. Improve processes for partner recruitment, partner management, communications, channel marketing, channel forecasting, collaborative selling, partner order management, channel service, and analytics for partners and channel managers.
Interaction center – Maximize customer loyalty, reduce costs, and boost revenue by transforming your interaction center into a strategic delivery channel for marketing, sales, and service efforts across all contact channels. Activities such as telemarketing, telesales, customer service, HR and IT help desk, and interaction center management are supported.
Web channel – Increase sales and reduce transaction costs by turning the Internet into a valuable sales, marketing, and service channel for businesses and consumers. Increase profitability and reach new markets with functionality for e-marketing, e-commerce, e-service, and Web channel analytics. Deploy these capabilities directly against SAP ERP or with SAP CRM as a fully integrated customer channel.
Business communications management – Manage inbound and outbound contacts across multiple locations and communications channels effectively and efficiently. By integrating multichannel communications with your customer-facing business processes, you can provide your customers and partners with a smooth, consistent experience across all avenues of contact, including voice, text messaging, Web contacts, and e-mail.

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Security : Steganography

2007-09-30T10:49:00.000+05:30

Over the past couple of years, steganography has been the source of a lot of discussion, particularly as it was suspected that terrorists connected with the September 11 attacks might have used it for covert communications. While no such connection has been proven, the concern points out the effectiveness of steganography as a means of obscuring data. Indeed, along with encryption, steganography is one of the fundamental ways by which data can be kept confidential. This article will offer a brief introductory discussion of steganography: what it is, how it can be used, and the true implications it can have on information security.

What is Steganography?

While we are discussing it in terms of computer security, steganography is really nothing new, as it has been around since the times of ancient Rome. For example, in ancient Rome and Greece, text was traditionally written on wax that was poured on top of stone tablets. If the sender of the information wanted to obscure the message - for purposes of military intelligence, for instance - they would use steganography: the wax would be scraped off and the message would be inscribed or written directly on the tablet, wax would then be poured on top of the message, thereby obscuring not just its meaning but its very existence[1].

According to Dictionary.com, steganography (also known as "steg" or "stego") is "the art of writing in cipher, or in characters, which are not intelligible except to persons who have the key; cryptography" [2]. In computer terms, steganography has evolved into the practice of hiding a message within a larger one in such a way that others cannot discern the presence or contents of the hidden message[3]. In contemporary terms, steganography has evolved into a digital strategy of hiding a file in some form of multimedia, such as an image, an audio file (like a .wav or mp3) or even a video file.

What is Steganography Used for?

Like many security tools, steganography can be used for a variety of reasons, some good, some not so good. Legitimate purposes can include things like watermarking images for reasons such as copyright protection. Digital watermarks (also known as fingerprinting, significant especially in copyrighting material) are similar to steganography in that they are overlaid in files, which appear to be part of the original file and are thus not easily detectable by the average person. Steganography can also be used as a way to make a substitute for a one-way hash value (where you take a variable length input and create a static length output string to verify that no changes have been made to the original variable length input)[4]. Further, steganography can be used to tag notes to online images (like post-it notes attached to paper files). Finally, steganography can be used to maintain the confidentiality of valuable information, to protect the data from possible sabotage, theft, or unauthorized viewing[5].

Unfortunately, steganography can also be used for illegitimate reasons. For instance, if someone was trying to steal data, they could conceal it in another file or files and send it out in an innocent looking email or file transfer. Furthermore, a person with a hobby of saving pornography, or worse, to their hard drive, may choose to hide the evidence through the use of steganography. And, as was pointed out in the concern for terroristic purposes, it can be used as a means of covert communication. Of course, this can be both a legitimate and an illegitimate application.

Steganography Tools

There are a vast number of tools that are available for steganography. An important distinction that should be made among the tools available today is the difference between tools that do steganography, and tools that do steganalysis, which is the method of detecting steganography and destroying the original message. Steganalysis focuses on this aspect, as opposed to simply discovering and decrypting the message, because this can be difficult to do unless the encryption keys are known.

A comprehensive discussion of steganography tools is beyond the scope of this article. However, there are many good places to find steganography tools on the Net. One good place to start your search for stego tools is on Neil Johnson's Steganography and Digital Watermarking Web site. The site includes an extensive list of steganography tools. Another comprehensive tools site is located at the StegoArchive.com.

For steganalysis tools, a good site to start with is Neil Johnson's Steganalysis site. Niels Provos's site, is also a great reference site, but is currently being relocated, so keep checking back on its progress.

The plethora of tools available also tends to span the spectrum of operating systems. Windows, DOS, Linux, Mac, Unix: you name it, and you can probably find it.

How Do Steganography Tools Work?

To show how easy steganography is, I started out by downloading one of the more popular freeware tools out now: F5, then moved to a tool called SecurEngine, which hides text files within larger text files, and lastly a tool that hides files in MP3s called MP3Stego. I also tested one commercial steganography product, Steganos Suite.

F5 was developed by Andreas Westfield, and runs as a DOS client. A couple of GUIs were later developed: one named "Frontend", developed by Christian Wohne and the other, named "Stegano", by Thomas Biel. I tried F5, beta version 12. I found it very easy to encode a message into a JPEG file, even if the buttons in the GUI are written in German! Users can simply do this by following the buttons, inputting the JPEG file path, then the location of the data that is being hidden (in my case, I used a simple text file created in Notepad), at which point the program prompts the user for a pass phrase. As you can see by the before and after pictures below, it is very hard to tell them apart, embedded message or not.

Steganography and Security

As mentioned previously, steganography is an effective means of hiding data, thereby protecting the data from unauthorized or unwanted viewing. But stego is simply one of many ways to protect the confidentiality of data. It is probably best used in conjunction with another data-hiding method. When used in combination, these methods can all be a part of a layered security approach. Some good complementary methods include:

Encryption - Encryption is the process of passing data or plaintext through a series of mathematical operations that generate an alternate form of the original data known as ciphertext. The encrypted data can only be read by parties who have been given the necessary key to decrypt the ciphertext back into its original plaintext form. Encryption doesn't hide data, but it does make it hard to read!

Hidden directories (Windows) - Windows offers this feature, which allows users to hide files. Using this feature is as easy as changing the properties of a directory to "hidden", and hoping that no one displays all types of files in their explorer.

Hiding directories (Unix) - in existing directories that have a lot of files, such as in the /dev directory on a Unix implementation, or making a directory that starts with three dots (...) versus the normal single or double dot.

Covert channels - Some tools can be used to transmit valuable data in seemingly normal network traffic. One such tool is Loki. Loki is a tool that hides data in ICMP traffic (like ping).

Protecting Against Malicious Steganography

Unfortunately, all of the methods mentioned above can also be used to hide illicit, unauthorized or unwanted activity. What can you do to prevent or detect issues with stego? There is no easy answer. If someone has decided to hide their data, they will probably be able to do so fairly easily. The only way to detect steganography is to be actively looking for in specific files, or to get very lucky. Sometimes an actively enforced security policy can provide the answer: this would require the implementation of company-wide acceptable use policies that restrict the installation of unauthorized programs on company computers.

Using the tools that you already have to detect movement and behavior of traffic on your network may also be helpful. Network intrusion detection systems can help administrators to gain an understanding of normal traffic in and around your network and can thus assist in detecting any type of anomaly, especially with any changes in the behavior of increased movement of large images around your network. If the administrator is aware of this sort of anomalous activity, it may warrant further investigation. Host-based intrusion detection systems deployed on computers may also help to identify anomalous storage of image and/or video files.

A research paper by Stefan Hetzel cites two methods of attacking steganography, which really are also methods of detecting it. They are the visual attack (actually seeing the differences in the files that are encoded) and the statistical attack: "The idea of the statistical attack is to compare the frequency distribution of the colors of a potential stego file with the theoretically expected frequency distribution for a stego file." It might not be the quickest method of protection, but if you suspect this type of activity, it might be the most effective. For JPEG files specifically, a tool called Stegdetect, which looks for signs of steganography in JPEG files, can be employed. Stegbreak, a companion tool to Stegdetect, works to decrypt possible messages encoded in a suspected steganographic file, should that be the path you wish to take once the stego has been detected.

Conclusions

Steganography is a fascinating and effective method of hiding data that has been used throughout history. Methods that can be employed to uncover such devious tactics, but the first step are awareness that such methods even exist. There are many good reasons as well to use this type of data hiding, including watermarking or a more secure central storage method for such things as passwords, or key processes. Regardless, the technology is easy to use and difficult to detect. The more that you know about its features and functionality, the more ahead you will be in the game.

Resources:

[1] Steganography, by Neil F. Johnson, George Mason University,
http://www.jjtc.com/stegdoc/sec202.html

[2] http://dictionary.reference.com/search?q=steganography

[3] The Free On-line Dictionary of Computing, © 1993-2001 Denis Howe
http://www.nightflight.com/foldoc/index.html

[4] Applied Cryptography, Bruce Schneier, John Wiley and Sons Inc., 1996

[5] Steganography: Hidden Data, by Deborah Radcliff, June 10, 2002,
http://www.computerworld.com/securitytopics/security/story/0,10801,71726,00.html

SPM:Software Project Managment

2007-09-28T19:55:00.000+05:30

Project Schedule

The project schedule is the core of the project plan. It is used by the project manager to commit people to the project and show the organization how the work will be performed. Schedules are used to communicate final deadlines and, in some cases, to determine resource needs. They are also used as a kind of checklist to make sure that every task necessary is performed. If a task is on the schedule, the team is committed to doing it. In other words, the project schedule is the means by which the project manager brings the team and the project under control.
Project ScheduleThe project schedule is a calendar that links the tasks to be done with the resources that will do them. Before a project schedule can be created, the project manager must have a work breakdown structure (WBS), an effort estimate for each task, and a resource list with availability for each resource. If these are not yet available, it may be possible to create something that looks like a schedule, but it will essentially be a work of fiction. A project manager’s time is better spent on working with the team to create a WBS and estimates (using a consensus-driven estimation method like Wideband Delphi—see Chapter 3) than on trying to build a project schedule without them. The reason for this is that a schedule itself is an estimate: each date in the schedule is estimated, and if those dates do not have the buy-in of the people who are going to do the work, the schedule will almost certainly be inaccurate.
The Wideband Delphi process is explained in detail in Chapter 3: Estimation. Read the full text of Chapter 3 (PDF)There are many project scheduling software products which can do much of the tedious work of calculating the schedule automatically, and plenty of books and tutorials dedicated to teaching people how to use them. However, before a project manager can use these tools, he should understand the concepts behind the WBS, dependencies, resource allocation, critical paths, Gantt charts and earned value. These are the real keys to planning a successful project.The most popular tool for creating a project schedule is Microsoft Project. There are also free and open source project scheduling tools available for most platforms which feature task lists, resource allocation, predecessors and Gantt charts. Other project scheduling software packages include:
Open Workbench
dotProject
netOffice
TUTOS
Allocate Resources to the TasksThe first step in building the project schedule is to identify the resources required to perform each of the tasks required to complete the project. (Generating project tasks is explained in more detail in the Wideband Delphi Estimation Process page.) A resource is any person, item, tool, or service that is needed by the project that is either scarce or has limited availability.Many project managers use the terms “resource” and “person” interchangeably, but people are only one kind of resource. The project could include computer resources (like shared computer room, mainframe, or server time), locations (training rooms, temporary office space), services (like time from contractors, trainers, or a support team), and special equipment that will be temporarily acquired for the project. Most project schedules only plan for human resources—the other kinds of resources are listed in the resource list, which is part of the project plan.One or more resources must be allocated to each task. To do this, the project manager must first assign the task to people who will perform it. For each task, the project manager must identify one or more people on the resource list capable of doing that task and assign it to them. Once a task is assigned, the team member who is performing it is not available for other tasks until the assigned task is completed. While some tasks can be assigned to any team member, most can be performed only by certain people. If those people are not available, the task must wait.
Identify DependenciesOnce resources are allocated, the next step in creating a project schedule is to identify dependencies between tasks. A task has a dependency if it involves an activity, resource, or work product that is subsequently required by another task. Dependencies come in many forms: a test plan can’t be executed until a build of the software is delivered; code might depend on classes or modules built in earlier stages; a user interface can’t be built until the design is reviewed. If Wideband Delphi is used to generate estimates, many of these dependencies will already be represented in the assumptions. It is the project manager’s responsibility to work with everyone on the engineering team to identify these dependencies. The project manager should start by taking the WBS and adding dependency information to it: each task in the WBS is given a number, and the number of any task that it is dependent on should be listed next to it as a predecessor. The following figure shows the four ways in which one task can be dependent on another.

Create the Schedule

Once the resources and dependencies are assigned, the software will arrange the tasks to reflect the dependencies. The software also allows the project manager to enter effort and duration information for each task; with this information, it can calculate a final date and build the schedule.

Each task is represented by a bar, and the dependencies between tasks are represented by arrows. Each arrow either points to the start or the end of the task, depending on the type of predecessor. The black diamond between tasks D and E is a milestone, or a task with no duration. Milestones are used to show important events in the schedule. The black bar above tasks D and E is a summary task, which shows that these tasks are two subtasks of the same parent task. Summary tasks can contain other summary tasks as subtasks. For example, if the team used an extra Wideband Delphi session to decompose a task in the original WBS into subtasks, the original task should be shown as a summary task with the results of the second estimation session as its subtasks.

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Security:Firewall Information

2007-09-28T15:40:00.000+05:30

What is a firewall?

A term borrowed either from construction—aircraft or automobile design--a firewall is a barrier that segregates two areas to protect one space from the environment of the other. In buildings or airframes, it is designed to prevent fire from spreading from one section to another. In racing, it protects the driver from a possible fuel tank fire. Also in automobiles, the bulkhead separating the engine compartment from the passenger compartment is called a firewall.

In computing terms, a firewall isolates a computer or network from another computer or network. Most often, this creates a so-called "trusted zone" on the inside of the firewall (your local network), which is protected from the untrusted zone outside (the internet). Some network firewalls sit between sections of the network; this creates DMZs, or De-Militarized Zones, referring to the military term for areas that separate two opposing factions to reduce the risk of war. Certain devices, such as public web servers, that need to interface more with untrusted zones will be in the DMZ with a firewall between them and the local network, offering more protection for that network.

As with firewalls in buildings, a certain amount of penetration of the firewall is allowed, but these penetrations, or ports, are controlled and safeguarded against bad stuff trying to get in.

Ports

In networking, one will often hear the term port. Ports, according to the Internet Assigned Numbers Authority (IANA, which coordinates functions for the internet), "name the ends of logical connections which carry long term conversations. For the purpose of providing services to unknown callers, a service contact port is defined." Essentially, this is an addressing scheme that allows the computer to assign meaning to incoming and outgoing information.

Ports fall into three categories:

Port numbers that range from 0 through 1023 are called Well Known Ports. On most systems, they can only be used by system (or root) processes or by programs executed by privileged users. The IANA has assigned specific uses for most of these ports.
The Registered Ports are those from 1024 through 49151 and can be used by ordinary user processes or programs executed by ordinary users. Many of these ports are also assigned.
The Dynamic and/or Private Ports are those from 49152 through 65535. The name is self-explanatory; they are not assigned.

So what firewalls do is filter the data coming into them, allowing information for certain ports to go through and rejecting others, according to preset rules. There are three different ways this is done:

Packet filtering - Packets (small chunks of data) are analyzed against a set of filters

Proxy service - Doesn't accept packets coming in from the untrusted zone unless they were specifically requested by a computer in the trusted zone.

Stateful inspection - Doesn't examine the entire incoming packet, but compares certain key parts of that packet to defining characteristics derived from packets traveling inside the firewall to the outside.

Internet: Internet Radio

2007-09-27T12:18:00.000+05:30

Internet radio (aka e-Radio) is an audio broadcasting service transmitted via the Internet. Broadcasting on the Internet is usually referred to as webcasting since it is not transmitted broadly through wireless means but is delivered over the World Wide Web. The term "e-Radio" suggests a streaming medium that presents listeners with a continuous stream of audio to which they have no control much like traditional broadcast media. It is not synonymous with podcasting which involves downloading and therefore copyright issues. Nor does e-Radio suggest "on-demand" file serving. Many Internet "radio stations" are associated with a corresponding traditional "terrestrial" radio station or radio network. Internet-only radio stations are usually independent of such associations.

Internet radio "stations" are usually accessible from anywhere in the world—for example, to listen to an Australian station from Europe or America. This makes it a popular service for expatriates and for listeners with interests not adequately served by local radio stations (such as progressive rock, anime themed music, classical music, 24-hour stand up comedy, and others). Some Internet radio services offer news, sports, talkback, and various genres of music—everything that is on the radio station being simulcast over the internet with a netcast stream.

Freedom of the Airwaves
Radio broadcasting began in the early 20s, but it wasn't until the introduction of the transistor radio in 1954 that radio became available in mobile situations. Internet radio is in much the same place. Until the 21st century, the only way to obtain radio broadcasts over the Internet was through your PC. That will soon change, as wireless connectivity will feed Internet broadcasts to car radios, PDAs and cell phones. The next generation of wireless devices will greatly expand the reach and convenience of Internet radio.

Uses and Advantages
Traditional radio station broadcasts are limited by two factors:
• The power of the station's transmitter (typically 100 miles)
• The available broadcast spectrum (you might get a couple of dozen radio stations locally)
Internet radio has no geographic limitations, so a broadcaster in Kuala Lumpor can be heard in Kansas on the Internet. The potential for Internet radio is as vast as cyberspace itself.

In comparison to traditional radio, Internet radio is not limited to audio. An Internet radio broadcast can be accompanied by photos or graphics, text and links, as well as interactivity, such as message boards and chat rooms. This advancement allows a listener to do more than listen. In the example at the beginning of this article, a listener who hears an ad for a computer printer ordered that printer through a link on the Internet radio broadcast Web site. The relationship between advertisers and consumers becomes more interactive and intimate on Internet radio broadcasts. This expanded media capability could also be used in other ways. For example, with Internet radio, you could conduct training or education and provide links to documents and payment options. You could also have interactivity with the trainer or educator and other information on the Internet radio broadcast site.

Internet radio programming offers a wide spectrum of broadcast genres, particularly in music. Broadcast radio is increasingly controlled by smaller numbers of media conglomerates. In some ways, this has led to more mainstreaming of the programming on broadcast radio, as stations often try to reach the largest possible audience in order to charge the highest possible rates to advertisers. Internet radio, on the other hand, offers the opportunity to expand the types of available programming. The cost of "getting on the air" is less for an Internet broadcaster and Internet radio can appeal to "micro-communities" of listeners focused on special music or interests.

Unix: The Unix Philosophy

2007-09-21T11:38:00.000+05:30

Essentially, UNIX is made up of files. In fact, every aspect of UNIX is looked at as a file. When we write some data to be displayed on screen for example, the data is actually written to a screen file and then a certain device driver in the kernel is activated. This controls a particular device, in our case the screen. And the contents of the screen file are displayed on the screen. Files that relate to hardware are known as "special files".

We have one universal file - unix itself. But this file is broken up into many other smaller file systems. By default, i.e. when we install UNIX, there is one root and two user file systems created. Normally file systems correspond to physical sections of the disk, basically the root file system and many user file systems.

These file systems are again broken up into directories (which are again viewed as files) and files. These directories can further have sub-directories and files giving rise to a hierarchical tree-like structure.

In DOS, we sometimes divide the disk into logical sections like C and D. Each of these logical drives has its own set of directories and files. To move from one drive to another we just need to specify the drive as the DOS prompt and hit enter.

But while we are at one drive we can access a file from another drive. Now both these drives are always available by default. In UNIX there is a slight difference. While the root file system and the two user file systems that are created by default are loaded, access to any other file system is only possible if they are explicitely mounted. Mounting means nothing but loading them into memory. And considering that file systems are viewed by UNIX as files, if a time comes for them to be accessed, they have to be in memory (as like any other file).

For example, the floppy drive. This too is considered by UNIX as a file. And read or write to a floppy drive is first done in a "special file", from which then the contents are transferred to actual floppy. But to be able to access the floppy drive through the file connected to it, the file has to be mounted i.e. in memory.

New Technology:RFID from Microsoft

2007-09-21T09:49:00.000+05:30

Executive Summary

Whatever you read about packaging, supply chains, or identification, you will come across an article or advertisement for Radio Frequency Identification (RFID). Why does it seem that this technology is being touted as the best thing since sliced bread? And is it just another piece of hype meant to confuse and make us invest money in another piece of technology?

RFID is evolving as a major technology enabler for identifying and tracking goods and assets around the world. It can help hospitals locate expensive equipment more quickly to improve patient care, pharmaceutical companies to reduce counterfeiting, and logistics providers to improve the management of moveable assets. It also promises to enable new efficiencies in the supply chain by tracking goods from the point of manufacture through to the retail point of sale (POS).

As a result of the potential benefits of RFID:

The automotive industry has been using closed-loop RFID systems to track and control major assemblies within a production plant for over 30 years.
Many of the world's major retailers have mandated RFID tagging for pallets and cases shipped into their distribution centers to provide better visibility.
There are moves in the defense and aerospace industry to mandate the use of RFID to improve supply chain visibility and ensure the authenticity of parts.
Regulatory bodies in the United States are moving to the use of ePedigrees based on RFID to prevent the counterfeiting of prescription drugs.
Hospitals are using RFID for patient identification and moveable asset tracking.
RFID tags are being used to track the movement of farm animals to assist with tracking issues when major animal diseases strike.

But while the technology has received more than its fair share of media coverage recently, many are still unfamiliar with RFID and the benefits it can offer. In the face of this need for clear, comprehensive information about RFID and its benefits, this paper defines the opportunities offered by the technology for all organizations involved in the production, movement, or sale of goods. It is equally relevant for organizations wishing to track or locate existing goods, assets, or equipment.

In addition, the paper seeks to outline the business and technical challenges to RFID deployment and demonstrates how these issues can be addressed with technology from Microsoft and its partners. Above all, it explains how Microsoft technology—which provides the software architecture underpinning the solution rather than the tags or readers—can support the deployment of RFID-based solutions.

What Is RFID Really?

But what is RFID? RFID is the reading of physical tags on single products, cases, pallets, or re-usable containers that emit radio signals to be picked up by reader devices. These devices and software must be supported by a sophisticated software architecture that enables the collection and distribution of location-based information in near real time. The complete RFID picture combines the technology of the tags and readers with access to global standardized databases, ensuring real time access to up-to-date information about relevant products at any point in the supply chain. A key component to this RFID vision is the EPC Global Network.

Tags contain a unique identification number called an Electronic Product Code (EPC), and potentially additional information of interest to manufacturers, healthcare organizations, military organizations, logistics providers, and retailers, or others that need to track the physical location of goods or equipment. All information stored on RFID tags accompanies items as they travel through a supply chain or other business process. All information on RFID tags, such as product attributes, physical dimensions, prices, or laundering requirements, can be scanned wirelessly by a reader at high speed and from a distance of several meters.

RFID Bill of Materials

So what is the bill of materials for RFID then? RFID Component parts are:

Tag or Transponder—An RFID tag is a tiny radio device that is also referred to as a transponder, smart tag, smart label, or radio barcode. The tag comprises a simple silicon microchip (typically less than half a millimeter in size) attached to a small flat aerial and mounted on a substrate. The whole device can then be encapsulated in different materials (such as plastic) dependent upon its intended usage. The finished tag can be attached to an object, typically an item, box, or pallet, and read remotely to ascertain its identity, position, or state. For an active tag there will also be a battery.

Reader or Interrogator—The reader—sometimes called an interrogator or scanner—sends and receives RF data to and from the tag via antennas. A reader may have multiple antennas that are responsible for sending and receiving radio waves.

Host Computer—The data acquired by the readers is then passed to a host computer, which may run specialist RFID software or middleware to filter the data and route it to the correct application, to be processed into useful information.

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Mobile Computing:Mobile IP-Part-III

2007-09-21T09:30:00.000+05:30

Mobile Computing is becoming increasingly important due to the rise in the number of portable computers and the desire to have continuous network connectivity to the Internet irrespective of the physical location of the node. The Internet infrastructure is built on top of a collection of protocols, called the TCP/IP protocol suite. Transmission Control Protocol (TCP) and Internet Protocol (IP) are the core protocols in this suite. IP requires the location of any host connected to the Internet to be uniquely identified by an assigned IP address. This raises one of the most important issues in mobility, because when a host moves to another physical location, it has to change its IP address. However, the higher level protocols require IP address of a host to be fixed for identifying connections. The Mobile Internet Protocol (Mobile IP) is an extension to the Internet Protocol proposed by the Internet Engineering Task Force (IETF) that addresses this issue. It enables mobile computers to stay connected to the Internet regardless of their location and without changing their IP address. More precisely, Mobile IP is a standard protocol that builds on the Internet Protocol by making mobility transparent to applications and higher level protocols like TCP [6]. This article provides an introduction to Mobile IP and discusses its advantages and

Overview of the Protocol

Mobile IP supports mobility by transparently binding the home address of the mobile node with its care-of address. This mobility binding is maintained by some specialized routers known as mobility agents. Mobility agents are of two types - home agents and foreign agents. The home agent, a designated router in the home network of the mobile node, maintains the mobility binding in a mobility binding table where each entry is identified by the tuple . Figure 1 shows a mobility binding table. The purpose of this table is to map a mobile node's home address with its care-of address and forward packets accordingly.
Foreign agents are specialized routers on the foreign network where the mobile node is currently visiting. The foreign agent maintains a visitor list which contains information about the mobile nodes currently visiting that network. Each entry in the visitor list is identified by the tuple: <>. Figure 2 shows an instance of a visitor list.
In a typical scenario, the care-of address of a mobile node is the foreign agent's IP address. There can be another kind of care-of address, known as colocated care-of address, which is usually obtained by some external address assignment mechanism.

The basic Mobile IP protocol has four distinct stages [2]. These are:

Agent Discovery: Agent Discovery consists of the following steps:
1. Mobility agents advertise their presence by periodically broadcasting Agent Advertisement messages. An Agent Advertisement message lists one or more care-of addresses and a flag indicating whether it is a home agent or a foreign agent.
2. The mobile node receiving the Agent Advertisement message observes whether the message is from its own home agent and determines whether it is on the home network or a foreign network.
3. If a mobile node does not wish to wait for the periodic advertisement, it can send out Agent Solicitation messages that will be responded by a mobility agent.
Registration: Registration consists of the following steps:
1. If a mobile node discovers that it is on the home network, it operates without any mobility services.
2. If the mobile node is on a new network, it registers with the foreign agent by sending a Registration Request message which includes the permanent IP address of the mobile host and the IP address of its home agent.
3. The foreign agent in turn performs the registration process on behalf of the mobile host by sending a Registration Request containing the permanent IP address of the mobile node and the IP address of the foreign agent to the home agent.
4. When the home agent receives the Registration Request, it updates the mobility binding by associating the care-of address of the mobile node with its home address.
5. The home agent then sends an acknowledgement to the foreign agent.
6. The foreign agent in turn updates its visitor list by inserting the entry for the mobile node and relays the reply to the mobile node.
Figure 3 illustrates the registration process.

3.In Service: This stage can be subdivided into the following steps:

When a correspondent node wants to communicate with the mobile node, it sends an IP packet addressed to the permanent IP address of the mobile node.
The home agent intercepts this packet and consults the mobility binding table to find out if the mobile node is currently visiting any other network.
The home agent finds out the mobile node's care-of address and constructs a new IP header that contains the mobile node's care-of address as the destination IP address. The original IP packet is put into the payload of this IP packet. It then sends the packet. This process of encapsulating one IP packet into the payload of another is known as IP-within-IP encapsulation [11], or tunneling.
When the encapsulated packet reaches the mobile node's current network, the foreign agent decapsulates the packet and finds out the mobile node's home address. It then consults the visitor list to see if it has an entry for that mobile node.
If there is an entry for the mobile node on the visitor list, the foreign agent retrieves the corresponding media address and relays it to the mobile node.
When the mobile node wants to send a message to a correspondent node, it forwards the packet to the foreign agent, which in turn relays the packet to the correspondent node using normal IP routing.
The foreign agent continues serving the mobile node until the granted lifetime expires. If the mobile node wants to continue the service, it has to reissue the Registration Request.

Figure 4 illustrates the tunneling operation.
4.Deregistration: If a mobile node wants to drop its care-of address, it has to deregister with its home agent. It achieves this by sending a Registration Request with the lifetime set to zero. There is no need for deregistering with the foreign agent as registration automatically expires when lifetime becomes zero. However if the mobile node visits a new network, the old foreign network does not know the new care-of address of the mobile node. Thus datagrams already forwarded by the home agent to the old foreign agent of the mobile node are lost.

IT News:Microsoft

2007-09-21T09:23:00.000+05:30

MS in talks with retail chains for RFID software

MICROSOFT is in talks with retail biggies, financial service providers and government agencies for its new radio frequency identification device (RFID) software. The software, called Microsoft Biztalk server 2006 R2, can be used across sectors to improve business processes such as asset tracking, supply chain management and inventory control. This is possible as the software enables all types of RFID to become fully compatible with the Microsoft platform.
The US retail chain Wal-Mart adopted radio frequency identification device software nearly three years ago to improve its back-end operations. Retail chains in India could take a cue and use the new platform for inventory management. Banks, on the other hand, can use it to track transaction records or even their high-networth clients. RFID solutions
can be used for e-passports as well.
BizTalk RFID was developed at the MIDC centre in Hyderabad. Microsoft has tied up with over 100 partners including HP, Intel, TCS, small software and hardware vendors to develop the platform. In fact, TCS was among the early movers in developing RFID applications. “We have implemented this technology for ITC’s cigarette unit in Kolkata,” said Pradeep Misra, centre of excellence (RFID), TCS.
HP is also implementing the technology for Bajaj Auto in partnership with Microsoft. The technology can also serve many other enterprises. “With the drop in hardware prices and devices becoming standardised, RFID technology will become affordable. With our easy to use software, RFID technology will be ready for mass adoption in due course, said Srini Koppolu, corporate vice-president, Microsoft India Development Centre.

Info: Ada Lovelace - First programmer

2007-09-20T11:47:00.000+05:30

Lovelace was the daughter of Lord Byron and assistant to the mathematician, Charles Babbage, the inventor of the computer, and became the first computer programmer.

Augusta Ada Byron was born on 10th December 1815, in London, the daughter of the poet George Gordon Byron and Annabella Milbanke Byron. On 21st April 1816, Byron separated from his wife and left Britain for ever, leaving his wife and daughter, never to see them again.

Ada was educated privately by tutors and by her mother, who had an abiding interest in mathematics. Lord Byron once called her ‘the princess of parallelograms’. Her mother gave Ada regular lessons in maths, in the hope that the logical discipline would inhibit the onset of madness, which Annabella thought existed in the Byron family.

In 1835, Ada married William King, 8th Baron King and, when he was created an earl in 1838, she became countess of Lovelace. She became acquainted with Mary Somerville, a noted scientific author, who introduced her in turn to Charles Babbage, the inventor of a calculating machine, later to become known as the computer. She told Babbage that she was well acquainted with mathematics and offered to help with the construction of his machine. Babbage doubted that a woman would have sufficient knowledge of mathematics, to be of any value to him, but when Ada added that she had some knowledge of languages, Babbage hired her as a translator.
In 1843, Ada translated and annotated an article written by the Italian mathematician and engineer, Luigi Federico Menabrea, who had proposed new functions for Babbage’s Analytical Machine. Ada not only translated the article, but added her own details and annotations. Her elaborate annotations, especially her description of how the Analytical Engine could be programmed to compute and make calculations beyond the power of the human brain, earned her the title of first computer programmer. She wrote in her notes ‘the Analytical Engine weaves algebraic patterns, just as the Jacquard-loom weaves flowers and leaves.’ She added ‘the Engine might compose elaborate and scientific pieces of music of any degree of complexity or extent.’

In 1852, at the age of 36, Ada contracted cancer and was put in the care of physicians who recommended bloodletting. Unfortunately they went too far, as was often the case in the Nineteenth Century, and she bled to death. She died on 29th November 1852 and was buried with her father at the Byron family church in Hucknall.

The programming language Ada is named after her.

Mobile Computing:Mobile IP-Part-I

2007-09-20T09:35:00.000+05:30

Introduction:-Mobile IP is the underlying technology for support of various mobile data and wireless networking applications. For example, GPRS depends on mobile IP to enable the relay of messages to a GPRS phone via the SGSN from the GGSN without the sending needing to know the serving node IP address.
The Impetus for Mobile IP:-With the advent of packet based mobile data applications and the increase of wireless computing, there is a corresponding need for the ability for seamless communication between the mobile node device and the packet data network (PDN) such as the Internet.
Mobile IP Definitions:-

Mobile Node: A device capable of performing network roaming

Home Agent: A router on the home network which serves as the a point for communications with the mobile node.

Foreign Agent: A router that functions as the mobile node's point of attachment when it travels to the foreign network.

Care of Address: Termination point of the tunnel toward the mobile node when it is not in the home network.

Correspondent Node: The device that the mobile node is communicating with such as a web server

Mobile IP in Operation:-

To accomplish this, mobile IP established the visited network as a foreign node and the home network as the home node. Mobile IP uses a tunneling protocol to allow messages from the PDN to be directed to the mobile node's IP address. This is accomplished by way of routing messages to the foreign node for delivery via tunneling the original IP address inside a packet destined for the temporary IP address assigned to the mobile node by the foreign node. The Home Agent and Foreign Agent continuously advertise their services on the network through an Agent Discovery process, enabling the Home Agent to recognize when a new Foreign Agent is aquired and allowing the Mobile Node to register a new Care of Address.

This method allows for seamless communications between the mobile node and applications residing on the PDN, allowing for seamless, always-on connectivity for mobile data applications and wireless computing.

Mobile IP enabled Applications:-Mobile IP technology is embedded in the functionality of packet equipment for 2.5G and 3G. In addition, mobile IP enables advanced applications such as unified messaging.

Additional Resources:-Books

Mobile Computing:-Introduction Part-II

2007-09-19T13:49:00.000+05:30

Wireless Networks:-
-Two types
1)Voice network
Cellular systems (GSM, CDMA etc.)
2)Data network
WiFi, HiperLAN
-Networks are moving towards an integrated network
GPRS
Voice over WiFi

---Physical Layer (PHY)
-Binary (digital) data transmitted over airwave
-Requires antenna
-characterized by transmission range, power, modulation scheme, frequency range

--MAC Layer
-How wireless stations share the air medium and avoid contention to transmit data successfully
-“listen before you speak” or “speak at predetermined interval”
-Unique problems
Hidden node
Exposed node

--Network Layer
Responsible for facilitating multihop communication
Need to run some routing protocol
Traditional routing protocols may not work efficiently
Mobility at IP layer

--Transport Layer
Reliable Transport such as TCP may not work well in wireless medium
TCP inherently assumes that packet loss is due to congestion
Needs modification for wireless network

Mobile Computing:Introduction Part-I

2007-09-19T12:28:00.000+05:30

Mobile Computing is a generic term describing the application of small,
portable, and wireless computing and communication devices.
This includes devices like laptops with wireless LAN technology,
mobile phones, wearable computers
and Personal Digital Assistants (PDAs) with Bluetooth or IRDA interfaces,
and USB flash drives.

Mobile computing IS wireless computing. This means connectivity with less or zero wires.

notebookInstead of using cables, there are wireless network devices may be installed to access the network as long as there are equipment (like small cell sites) around that can provide wireless network access/services. A student or faculty with a laptop can move from one table to another without worrying about power cables to stay connected. That's mobility!

Some cellular phones are like actual computer units. They may be used to prepare reports, view videos, listen to music, and even control the TV! Amazing, isn't it!?

There are other equipment/devices that we use nowadays that function as regular desktop computer units -- e.g., notebooks, tablet computers (an advanced design of a notebook but really still a notebook), handheld computer or personal digital assistants (PDAs).

tablet pcIn some tablet PCs, one can detach the screen and continue using it like a notepad. The HP tablet shown here is an example of a table PC.

Wireless technologies include wireless devices (e.g., cell phones) and wireless networks (e.g., cellular phone network).

* B = types and different uses of wireless technologies in the University and in education
* C = types and different uses of mobile computing in the University and in education
* B = C = type and difference uses of regular computer, cell phones, PDAs

tablet pc- for e-mail, research, communication, e-learning, report preparation, playing/simulation, program access, watching videos, reading, et al.

The main benefit of using mobile/wireless computing is that a computer could be brought anywhere inside classrooms, conference rooms and yes, even in bedrooms and restrooms, in airports and in malls. What many companies do is issue notebooks to their sales people so they can bring their presentation materials, prepare proposals, and access information anywhere (i.e., with the use of cellphones to access the Internet). The cellphone-notebook set-up is expensive though.

tablet pc monitorSince 2001, "access points" have been installed within the campus. Access points are devices that provide wireless network connection among computer units (i.e., not just the computer units commonly seen).

DLSU is currently purchasing more access points so we can have better coverage. We'll increase the quantity gradually.

Since 2001, we have been lending out network cards in the library, so students and faculty members can borrow them (like a book) and install them in their notebooks and access Internet practically anywhere in the school grounds. Like cell phones, there are blind spots (i.e., the network cannot be accessed because there are no signals). These places are outside the range of the access points. To date, only a small number of students borrow these units as they are not yet aware of this. However, the figures are steadily increasing.

The security of communication via wireless network access is a major concern. Like tools, wireless access devices can be put to bad use. Some wireless network signals can be used to gain unauthorized access to data/information. To hamper this, network traffic needs to be encrypted. Newer versions are capable of this.

Java Struts:ActionServlet,Action Class,ActionForm

2007-09-19T10:31:00.000+05:30

ActionServlet:-The class org.apache.struts.action.ActionServlet is the called the ActionServlet. In the the Jakarta Struts Framework this class plays the role of controller. All the requests to the server goes through the controller. Controller is responsible for handling all the requests.
Action Class:-The Action is part of the controller. The purpose of Action Class is to translate the HttpServletRequest to the business logic. To use the Action, we need to Subclass and overwrite the execute() method. The ActionServlet (commad) passes the parameterized class to Action Form using the execute() method. There should be no database interactions in the action. The action should receive the request, call business objects (which then handle database, or interface with J2EE, etc) and then determine where to go next. Even better, the business objects could be handed to the action at runtime (IoC style) thus removing any dependencies on the model. The return type of the execute method is ActionForward which is used by the Struts Framework to forward the request to the file as per the value of the returned ActionForward object.
ActionForm:-An ActionForm is a JavaBean that extends org.apache.struts.action.ActionForm. ActionForm maintains the session state for web application and the ActionForm object is automatically populated on the server side with data entered from a form on the client side.

Linux: How to reset forgotten root password

2007-09-19T09:39:00.000+05:30

Sometimes, it may happen that you simply forget the root password. And its more frustrating if it is the only account on your system. What to do if this happens? Re-install the OS? No!!!
When one door closes, the other opens. We have another way to login to system.

There are various methods available for resetting a root password. The list includes booting into a single-user mode, booting using boot disk and edit the password file and mounting the drive on another computer and editing the password file.

In this post, I will list a simple yet useful method only. Others require a little more knowledge of OS-related operations and it may prove dangerous if you perform in a wrong way.

Reseting password by booting into single-user mode
This is the easiest and the fastest method to reset passwords. The steps are a little different depending on if you are using GRUB or LILO as a bootmanager.

For LILO
0) Reboot the system. When you see the LILO: prompt (see Fig. below), type in linux single and press 'Enter'. This will log you in as root in single-user mode. If your system requires you to enter your root password to log in, then try linux init=/bin/bash instead.

1) Once the system finishes booting, you will be logged in as root in single-user mode. Use passwd and choose a new password for root.

2) Type reboot to reboot the system and then you can login with the new password you just selected.

If you have a new version of LILO which gives you a menu selection of the various kernels available press Tab to get the LILO: prompt and then proceed as shown above.

For GRUB
0) Reboot the system, and when you are at the selection prompt (See Fig. below), highlight the line for Linux and press 'e'. You may only have 2 seconds to do this, so be quick.

1) This will take you to another screen where you should select the entry that begins with 'kernel' and press 'e' again.

2) Append ' single' to the end of that line (without the quotes). Make sure that there is a space between what's there and 'single'. If your system requires you to enter your root password to log into single-user mode, then append init=/bin/bash after 'single'. Hit 'Enter' to save the changes.

3) Press 'b' to boot into Single User Mode.

4) Once the system finishes booting, you will be logged in as root. Use passwd and choose a new password for root.

5) Type reboot to reboot the system, and you can login with the new password you just selected.

* Disclaimer *
Use the information in this document at your own risk. I completely deny any potential liability for the contents of this document. Use of the concepts, examples, and/or other content of this document is entirely at your own risk.
The information in this document should only be used to recover passwords from machines to which you have legal access. If you use this information to break into other people's systems, then I am not responsible for it and you deserve your fate when you are caught. So don't blame me.
You are strongly advised to make a backup of your system before performing any of the actions listed in this document.

Networking: How does Ping actually works?

2007-09-18T22:19:00.000+05:30

Ping is a basic Internet program that most of us use daily, but did you ever stop to wonder how it really worked?

• As the ping program initializes, it opens a raw ICMP socket so that it can employ IP directly, circumventing TCP and UDP.
• Ping formats an ICMP type 8 message, an Echo Request, and sends it (using the “sendto” function) to the designated target address. The system provides the IP header and the data link layer envelope.
• As ICMP messages are received, ping has the opportunity to examine each packet to pick out those items that are of interest.
• The usual behavior is to siphon off ICMP type 0 messages, Echo Replies, which have an identification field value that matches the program PID.
• Ping uses the timestamp in the data area of the Echo Reply to calculate a round-trip time. It also reports the TTL from the IP header of the reply.
• When things do not work normally, ping may report some of the other ICMP message types that show up in the inbox. This includes things like Destination Unreachable and Time Exceeded messages.

D: Why D?

2007-09-18T07:18:00.000+05:30

Continued from previous post...

Why, indeed. Who needs another programming language?
The software industry has come a long way since the C language was invented. Many new concepts were added to the language with C++, but backwards compatibility with C was maintained, including compatibility with nearly all the weaknesses of the original design. There have been many attempts to fix those weaknesses, but the compatibility issue frustrates it. Meanwhile, both C and C++ undergo a constant accretion of new features. These new features must be carefully fitted into the existing structure without requiring rewriting old code. The end result is very complicated - the C standard is nearly 500 pages, and the C++ standard is about 750 pages! C++ is a difficult and costly language to implement, resulting in implementation variations that make it frustrating to write fully portable C++ code.

C++ programmers tend to program in particular islands of the language, i.e. getting very proficient using certain features while avoiding other feature sets. While the code is usually portable from compiler to compiler, it can be hard to port it from programmer to programmer. A great strength of C++ is that it can support many radically different styles of programming - but in long term use, the overlapping and contradictory styles are a hindrance.
C++ implements things like resizable arrays and string concatenation as part of the standard library, not as part of the core language. Not being part of the core language has several suboptimal consequences.

Can the power and capability of C++ be extracted, redesigned, and recast into a language that is simple, orthogonal, and practical? Can it all be put into a package that is easy for compiler writers to correctly implement, and which enables compilers to efficiently generate aggressively optimized code?

Modern compiler technology has progressed to the point where language features for the purpose of compensating for primitive compiler technology can be omitted. (An example of this would be the 'register' keyword in C, a more subtle example is the macro preprocessor in C.) We can rely on modern compiler optimization technology to not need language features necessary to get acceptable code quality out of primitive compilers.

Certifications: Top 10 IT Certifications

2007-09-17T18:41:00.001+05:30

Best Hands-On Programs

Certifications in this category involve exams that not only test real-world skills and knowledge, but also demand that the test-takers demonstrate such skills and knowledge as a part of an exam or hands-on training. Such exams or programs are sometimes called “performance-based,” “practicum” or “laboratory” (lab) exams. Whatever name is used to identify these certifications, they all involve on-the-spot analysis and problem-solving and do their best to stage (or simulate) real-word system and hardware situations. Roll up your sleeves, and get your hands dirty while getting as close to a reality check as any certifications deliver today.

1. Cisco Certified Internetwork Expert (CCIE): With more than 10,000 CCIEs certified worldwide, this nonpareil credential includes a challenging, one-day lab exam that’s still widely regarded as the toughest certification exam around. Most CCIE candidates take the $1,250 lab exam—which also requires travel expenses for those who don’t live within driving distance of one of the 10 lab test centers around the globe—more than once to get certified. While neither cheap nor easy, the CCIE remains a valued prize as certifications go, which explains why it appears at or near the top of lists of the most desired or most valuable IT certifications.

See www.cisco.com/go/ccie.

2. Red Hat Certified Engineer (RHCE): The RHCE exams take an entire day and include about six hours worth of what the company calls performance-based exams—where candidates must install, configure or troubleshoot Red Hat servers and related network protocols and services. Highly regarded as representative of real-world situations and circumstances, these challenging exams also get high marks from certified professionals and their employers alike. The Red Hat Certified Technician (RHCT) exam is also performance-based and gets many of the same accolades. (It originally ranked as No. 4 in this list, but was dropped as a separate entry for brevity’s sake).

See www.redhat.com/training/rhce/courses/.

3. Novell Certified Directory Engineer (CDE): Novell calls the CDE exam a practicum, which requires logging into a carefully contrived and constructed set of networking components—servers, services and directories fully populated with users, groups, accounts, access controls and so forth—to analyze, design, configure, troubleshoot and repair the directories that make them work. Successful exam takers label the exam as demanding and intense, but also as an honest test of real-world knowledge and skills.

See www.novell.com/training/certinfo/cde/.

4. Oracle9i DBA Certified Professional (OCP): With the introduction of the Oracle9i DBA program, Oracle also now requires all candidates to complete an instructor-led hands-on course that involves significant real-world interaction and problem-solving, in addition to standard multiple-choice exams. This injects the kind of hands-on component needed to qualify for this list.

See www.oracle.com/education/certification/index.html?dba9i_ocp.html.

5. Oracle9i Database Administrator Certified Master (OCM): This credential requires a grueling two-day practicum exam administered at Oracle University locations. The exam’s still too new for a lot of intelligence to be available, but word is that it’s demanding, comprehensive and difficult.

See www.oracle.com/education/certification/index.html?dba9i_ocm.html.

6. Field Certified Systems Engineer (FCSE): Sponsored by the Field Certified Professional Association (FCPA), whose mission is to provide certifications based on the principles and practices of performance-based testing, the FCSE is available for Windows NT 4.0 and Windows 2000/XP environments, with numerous additional environments slated for coverage. Initial reports describe the credential as living up to its promise to identify individuals with real-world skills and knowledge appropriate for senior system engineering positions.

See www.fieldcertification.org/Exams/FCSE_Exams/FCSE_Exams.htm.

7. Field Certified Systems Administrator (FCSA): A more junior-level version of the FCSE, available for Windows NT 4.0, Windows 2000/XP and Cisco-based networking environments.

See www.fieldcertification.org/Exams/FCSA_Exams/FCSA_Exams.htm.

8. Field Certified PC Technician (FCPT): One of the Field Certified Help Desk Technician group of exams from the FCPA, this credential aims to identify individuals with real-world PC skills suitable for a bench technician, installer or help-desk professional. Numerous additional credentials in this general area are planned and should be worth watching.

See www.fieldcertification.org/Exams/FCHDT_Exams/FCPT_Exam/FCPT_Exam.htm.

9. Certified Professional Information Technology Consultant (CPITC): A certification from the Professional Standards Institute, an organization devoted to establishing performance-based credentials for all kinds of professionals, this credential covers a broad range of IT subject matter and must be supported with documentation and testing designed to measure real-world knowledge and expertise. The credential also carries hefty annual recertification requirements.

See www.professionalstandardsinstitute.com/cpitc.htm.

10. Cisco Career Certifications (Associate, Professional and Specialist): Although the various Cisco certifications beneath the CCIE do not include lab exams or practicums, they do make extensive use of simulation technology to include real-world problem-solving and to measure real-world skills as part (but not all) of the current exams relevant to these credentials. This makes them worthy of mention as the last item in this list.

See www.cisco.com/go/certification.

Technology : Dirty Secrets about working in IT

2007-09-17T18:29:00.003+05:30

If you are preparing for a career in IT or are new to IT, many of the “dirty little secrets” listed below may surprise you because we don’t usually talk about them out loud. If you are an IT veteran, you’ve probably encountered most of these issues and have a few of your own to add — and please, by all means, take a moment to add them to the discussion. Most of these secrets are aimed at network administrators, IT managers, and desktop support professionals. This list is not aimed at developers and programmers — they have their own set of additional dirty little secrets — but some of these will apply to them as well.

10.) The pay in IT is good compared to many other professions, but since they pay you well, they often think they own you

Although the pay for IT professionals is not as great as it was before the dot-com flameout and the IT backlash in 2001-2002, IT workers still make very good money compared to many other professions (at least the ones that require only an associate’s or bachelor’s degree). And there is every reason to believe that IT pros will continue to be in demand in the coming decades, as technology continues to play a growing role in business and society. However, because IT professionals can be so expensive, some companies treat IT pros like they own them. If you have to answer a tech call at 9:00 PM because someone is working late, you hear, “That’s just part of the job.” If you need to work six hours on a Saturday to deploy a software update to avoid downtime during business hours, you get, “There’s no comp time for that since you’re on salary. That’s why we pay you the big bucks!”

9.) It will be your fault when users make silly errors

Some users will angrily snap at you when they are frustrated. They will yell, “What’s wrong with this thing?” or “This computer is NOT working!” or (my personal favorite), “What did you do to the computers?” In fact, the problem is that they accidentally deleted the Internet Explorer icon from the desktop, or unplugged the mouse from the back of the computer with their foot, or spilled their coffee on the keyboard.

8.) You will go from goat to hero and back again multiple times within any given day

When you miraculously fix something that had been keeping multiple employees from being able to work for the past 10 minutes — and they don’t realize how simple the fix really was — you will become the hero of the moment and everyone’s favorite employee. But they will conveniently forget about your hero anointment a few hours later when they have trouble printing because of a network slowdown — you will be enemy No. 1 at that moment. But if you show users a handy little Microsoft Outlook trick before the end of the day, you’ll soon return to hero status.

7.) Certifications won’t always help you become a better technologist, but they can help you land a better job or a pay raise

Headhunters and human resources departments love IT certifications. They make it easy to match up job candidates with job openings. They also make it easy for HR to screen candidates. You’ll hear a lot of veteran IT pros whine about techies who were hired based on certifications but who don’t have the experience to effectively do the job. They are often right. That has happened in plenty of places. But the fact is that certifications open up your career options. They show that you are organized and ambitious and have a desire to educate yourself and expand your skills. If you are an experienced IT pro and have certifications to match your experience, you will find yourself to be extremely marketable. Tech certifications are simply a way to prove your baseline knowledge and to market yourself as a professional. However, most of them are not a good indicator of how good you will be at the job.

6.) Your nontechnical co-workers will use you as personal tech support for their home PCs

Your co-workers (in addition to your friends, family, and neighbors) will view you as their personal tech support department for their home PCs and home networks. They will e-mail you, call you, and/or stop by your office to talk about how to deal with the virus that took over their home PC or the wireless router that stopped working after the last power outage and to ask you how to put their photos and videos on the Web so their grandparents in Iowa can view them. Some of them might even ask you if they can bring their home PC to the office for you to fix it. The polite ones will offer to pay you, but some of them will just hope or expect you can help them for free. Helping these folks can be very rewarding, but you have to be careful about where to draw the line and know when to decline.

5.) Vendors and consultants will take all the credit when things work well and will blame you when things go wrong

Working with IT consultants is an important part of the job and can be one of the more challenging things to
manage. Consultants bring niche expertise to help you deploy specialized systems, and when everything works right, it’s a great partnership. But you have to be careful. When things go wrong, some consultants will try to push the blame off on you by arguing that their solution works great everywhere else so it must be a problem with the local IT infrastructure. Conversely, when a project is wildly successful, there are consultants who will try to take all of the credit and ignore the substantial work you did to customize and implement the solution for your company.

4.) You’ll spend far more time babysitting old technologies than implementing new ones

One of the most attractive things about working in IT is the idea that we’ll get to play with the latest cutting edge technologies. However, that’s not usually the case in most IT jobs. The truth is that IT professionals typically spend far more time maintaining, babysitting, and nursing established technologies than implementing new ones. Even IT consultants, who work with more of the latest and greatest technologies, still tend to work primarily with established, proven solutions rather than the real cutting edge stuff.

3.) Veteran IT professionals are often the biggest roadblock to implementing new technologies

A lot of companies could implement more cutting edge stuff than they do. There are plenty of times when upgrading or replacing software or infrastructure can potentially save money and/or increase productivity and profitability. However, it’s often the case that one of the largest roadblocks to migrating to new technologies is not budget constraints or management objections; it’s the veteran techies in the IT department. Once they have something up and running, they are reluctant to change it. This can be a good thing because their jobs depend on keeping the infrastructure stable, but they also use that as an excuse to not spend the time to learn new things or stretch themselves in new directions. They get lazy, complacent, and self-satisfied.

2.) Some IT professionals deploy technologies that do more to consolidate their own power than to help the business

Another subtle but blameworthy thing that some IT professionals do is select and implement technologies based on how well those technologies make the business dependent on the IT pros to run them, rather than which ones are truly best for the business itself. For example, IT pros might select a solution that requires specialized skills to maintain instead of a more turnkey solution. Or an IT manager might have more of a Linux/UNIX background and so chooses a Linux-based solution over a Windows solution, even though the Windows solution is a better business decision (or, vice versa, a Windows admin might bypass a Linux-based appliance, for example). There are often excuses and justifications given for this type of behavior, but most of them are disingenuous.

1.) IT pros frequently use jargon to confuse nontechnical business managers and hide the fact that they screwed up

All IT pros — even the very best — screw things up once in a while. This is a profession where a lot is at stake and the systems that are being managed are complex and often difficult to integrate. However, not all IT pros are good at admitting when they make a mistake. Many of them take advantage of the fact that business managers (and even some high-level technical managers) don’t have a good understanding of technology, and so the techies will use jargon to confuse them (and cover up the truth) when explaining why a problem or an outage occurred. For example, to tell a business manager why a financial application went down for three hours, the techie might say, “We had a blue screen of death on the SQL Server that runs that app. Damn Microsoft!” What the techie would fail to mention was that the BSOD was caused by a driver update he applied to the server without first testing it on a staging machine.

(Courtesy: TechRepublic)

Windows: How to Use Windows Notepad as a Professional Diary

2007-09-17T10:45:00.000+05:30

Use the following VERY easy steps to use Windows Notepad as your own diary, complete with a stamped date & time!

Step 0
First, open a new, blank Notepad file.

Step 1
Second, write .LOG as the first line of the file, and press ENTER. Save the Notepad file and then close it. Note: You must type .LOG in capital letters!

Step 2
Now relaunch the file. Notice how each time you open it, a new time/date entry is neatly placed on the body of the file. Each entry will appear below the previous one. Now you can take your notes more conveniently and organized. Hows trick?

Note: the word .LOG must be in CAPITAL LETTERS.

D: What is D?

2007-09-16T08:37:00.000+05:30

D is a general purpose systems and applications programming language. It is a higher level language than C++, but retains the ability to write high performance code and interface directly with the operating system API's and with hardware. D is well suited to writing medium to large scale million line programs with teams of developers. D is easy to learn, provides many capabilities to aid the programmer, and is well suited to aggressive compiler optimization technology.

D is not a scripting language, nor an interpreted language. It doesn't come with a VM, a religion, or an overriding philosophy. It's a practical language for practical programmers who need to get the job done quickly, reliably, and leave behind maintainable, easy to understand code.

D is the culmination of decades of experience implementing compilers for many diverse languages, and attempting to construct large projects using those languages. D draws inspiration from those other languages (most especially C++) and tempers it with experience and real world practicality.

C: How to use memcpy function in C

2007-09-14T13:49:00.000+05:30

The memcpy function in C++ copies the specified number of bytes of data from the specified source to the specified destination. This is a binary copy so the underlying data type is irrelevant. The following steps will help you use the memcpy function.

Step 0
Learn the syntax of memcpy in C++. The complete syntax is void *memcpy (void *destination, const void *source, size_t num);. Note that this function always copies num bytes and does not look for a terminating character in order to be as efficient as possible. Memcpy returns the destination array.

Step 1
Know that the pointers to the source and destination arrays are type-cast to a type of void. The size of the destination and source arrays should be at least num bytes to avoid overflows, although this is not required. Memmove should be considered as a safer approach if the source and destination overlap.

Step 2
Understand that the C++ memcpy function is kept in the cstring library. You may need to include the string.h header file to use memcpy.

Step 3
Look at the following complete program for some simple examples of how to use memcpy:

#include_<_stdio.h_>
#include_<_string.h_>
int main ()
{
__char string1[]="test string";
__char string2[80];
__memcpy (string2,string1,strlen(string1)+1);
__printf ("string1: %s\nstring2: %s\n",string1,string2);
__memcpy (string1,"",1);
__printf ("string1: %s\n",string1);
__return 0;
}

Observe the following output for this program:
string1: test string
string2: test string
string1:
The first use of memcpy copies the contents of string1 to the contents of string2. The second use of memcpy clears the contents of string1 by moving the null terminator character to the first position of string1.

Note: Please DO NOT copy-paste the code given in this post.

MINIX: What is MINIX 3?

2007-09-13T22:22:00.000+05:30

MINIX 3 is a new open-source operating system designed to be highly reliable, flexible, and secure. It is loosely based somewhat on previous versions of MINIX, but is fundamentally different in many key ways. MINIX 1 and 2 were intended as teaching tools; MINIX 3 adds the new goal of being usable as a serious system on resource-limited and embedded computers and for applications requiring high reliabilityThis new OS is extremely small, with the part that runs in kernel mode under 4000 lines of executable code. The parts that run in user mode are divided into small modules, well insulated from one another. For example, each device driver runs as a separate user-mode process so a bug in a driver (by far the biggest source of bugs in any operating system), cannot bring down the entire OS. In fact, most of the time when a driver crashes it is automatically replaced without requiring any user intervention, without requiring rebooting, and without affecting running programs. These features, the tiny amount of kernel code, and other aspects greatly enhance system reliability.

Hardware required
To run MINIX 3, you need a PC driven by a 386, 486, or Pentium CPU or compatible. The standard configuration requires 16 MB of RAM. An 8-MB version is also available, but it is slower due to a smaller buffer cache. Since the distribution comes on a live CD, you can test it without allocating any hard disk space, but for a hard disk installation, 50 MB is needed as a minimum, 600 MB minimum if you want all the sources.

Current status
The current version of MINIX 3 (3.1.2) is a work in progress. It is nowhere near as mature as FreeBSD or Linux right now. Ports to the Xscale and PowerPC are underway. Various programs and device drivers are being ported, and so on. People who would like to help develop a highly reliable operating system are more than welcome. Some projects that are needed are listed here. For more information, subscribe to the newsgroup: comp.os.minix

AJAX: What is AJAX?

2007-09-13T17:58:00.000+05:30

Ajax, or AJAX, is a web development technique used for creating interactive web applications. The intent is to make web pages feel more responsive by exchanging small amounts of data with the server behind the scenes, so that the entire web page does not have to be reloaded each time the user requests a change. This is intended to increase the web page's interactivity, speed, functionality, and usability.

Ajax is asynchronous in that loading does not interfere with normal page loading. JavaScript is the programming language in which Ajax function calls are made. Data retrieved using the technique is commonly formatted using XML, as reflected in the naming of the XMLHttpRequest object from which Ajax is derived.

Ajax is a cross-platform technique usable on many different operating systems, computer architectures, and Web browsers as it is based on open standards such as JavaScript and XML, together with open source implementations of other required technologies.

Windows: Why does the Recycle Bin have different file system names on FAT and NTFS?

2007-09-13T15:30:00.000+05:30

On FAT drives, the directory that stores files in the Recycle Bin is called C:\RECYCLED , but on NTFS drives, its name is C:\RECYCLER. Why the names change?

The FAT and NTFS Recycle Bins have different internal structure because NTFS has this thing called "security" and FAT doesn't. All recycled files on FAT drives are dumped into a single C:\RECYCLED directory, whereas recycled files on NTFS drives are separated based on the user's SID into directories named C:\RECYCLER\S-.... (It has nothing to do with whether you are running English or Swedish Windows).

Suppose the same directory name were used for both file systems, say, C:\RECYCLED. Since it is possible to upgrade a FAT drive to an NTFS drive with the CONVERT utility, this means that a FAT drive converted to NTFS would have a FAT-style Recycle Bin after the conversion. But since the names are the same, the Recycle Bin says, "Hey, look, here's a C:\RECYCLED directory. That must be my NTFS Recycle Bin!" except that it isn't. It's a FAT Recycle Bin left over from the conversion.

Giving the NTFS Recycle Bin a different name means that the Recycle Bin shell folder won't get confused by the "wrong" type of recycle bin directory structure on an NTFS volume.

Yes, the problem could have been solved some other way. For example, there could have been code to inspect the Recycle Bin directory to determine what format it is and ignore it if it didn't match the actual file system. (Or, if you're feeling really ambitious, somehow convert from one format to the other.) But that would be over-engineering. You have to write and test the detection (and possibly conversion) code, there's the risk of a false-positive, the code runs at every boot, and it needs to be maintained whenever either the FAT or NTFS recycle bin format changes. All for a scenario that happens at most once per drive.

Genral:Mr. Narayana Murthy

2007-09-13T09:43:00.000+05:30

THE other day, my wife and I were perhaps among the very few over 50-year-olds in the mostly-twentyish crowd watching the film Chak De in Bangalore. You had to be there to believe the shouts of joy that accompanied every goal

India

scored in the imaginary tournament in the movie. The mood at the end was as if

India

had actually won the women’s world cup in hockey. I can appreciate this mood since I too felt similar joy and pride when hundreds of cameras clicked at me holding our national flag, on India and my being declared the winners of the prestigious world entrepreneur award among the forty-odd competing nations at Monaco in 2003. As I exited the theatre after watching Chak De that day, several youngsters asked me for my reaction to the movie. My answer was simple. I said I wanted to see the movie become a reality not just in hockey but in every sphere. The recipe for such a success was most wonderfully conveyed by Shah Rukh Khan and those wonderful women hockey players in the movie. Let me recount them here. We have to identify as Indians first and rise above our affiliations with our states, religions and castes. We must accept meritocracy and enthusiastically play the role we are best suited to. We must embrace discipline to strictly follow every step required for success. We have to put the interest of our nation ahead of our personal interests, subordinating our egos and biases. Finally, we have to put in tremendous hard work and make shortterm sacrifices for long-term glory.
I have immense faith and optimism in the youth of this country. But, will we get our leaders to set examples for hundreds of millions of Indian youth? I wish more and more of our leaders see Chak De and learn these precious lessons.

Author is chairman and chief mentor,
Infosys Technologies

Windows Server 2008 Beta 3:Just Released

2007-09-13T01:05:00.000+05:30

After many months of waiting, Microsoft finally released the Beta 3 version of Windows Server 2008 (previously codenamed Longhorn), a major milestone pre-release version of the next version of Windows Server. (More recently, a CTP, or Community Technical Preview, version was distributed to beta testers in June 2007.) Windows Server 2008 has evolved quite a bit over time, and though the project hasn't suffered from the many feature drops and problems that dogged Windows Vista, there are certainly a somthing new in this version .

Download: Windows Server 2008 Beta 3 Enterprise Standard
Read more: Click here
and Here

Read Review:Review for MS server 2008

Windows : Why You Should NOT Upgrade to Windows Vista

2007-09-11T02:14:00.001+05:30

Why You Should NOT Upgrade to Windows Vista

Stiff Hardware Requirements:

DirectX 10 will be available only on Windows Vista. DirectX is useful for a variety of graphics and video functions, including business applications such as video conferencing. And if you must have the latest and greatest in games, the upgrade to Windows Vista is a no-brainer, as this is the only way you can get it. DirectX 10 also claims to fix the “small batch problem” from previous versions. It has claimed that this could lead to DirectX 10 games that can perform six times better than the same game running in DirectX 9 on Windows XP.

Learning Curve:

Vista is a different animal from previous Windows operating systems. Many of the tools are the same or similar, but there is still a lot to learn. If your IT department is already stretched thin, taking the time to learn and implement Windows Vista may not be worth it right now.

No Loss of WinXP Support:

Vista will be supported longer than XP, but XP still has two years of mainstream support from Microsoft. And a wealth of information on WinXP (and other operating systems) is already available on the internet. If you and your staff are comfortable with XP, there's little reason to upgrade to Vista for continued support at the moment.

Application Incompatibility:

Many popular applications do not work on Vista. Applications like ITunes and Nero have issues running on Vista. In fact, nearly every program involved in ripping or recoding media have issues with Vista. If these major applications are having compatibility issues, how many more small applications--those you may use everyday--will have problems, too?

DRM Issues:

Peter Gutmann from the UK's The Register has called Window Vista's new DRM the "longest suicide note in history." Even though great strides have been made for PCs in the living room as an entertainment device, Vista has put crippling DRM into place when playing next generation (HD-DVD and BluRay) content. When playing this content, the component output and S/PDIF output is disabled, effectively crippling Windows Vista as an entertainment system.

Notebook Battery Drain:

Windows Vista requires more hardware power to run--and notebook battery life goes down the more you require of your PC's hardware. Even just running the Aero Glass interface will drain your battery faster, due to the additional GPU processing. Any dedicated road warrior should consider this before upgrading.

Not so innovative:

You can download many advanced search applications for free. Even Microsoft has released one. Google has a nice sidebar with a built-in RSS reader available for free. Yahoo widgets (formally Konfabulator) allow you to change your desktop into a virtual workspace with all manner of data and tools available at your fingertips. Apple's OS X is by far the leader in modern desktops. Even Aero Glass cannot compare to the smoothness of OS X (which is more than five years old). Sun's Project Looking Glass can provide a minimal 3d desktop for XP for free.

Cost:

Vista is expensive. There's no way around this. Microsoft has tried to mitigate this by releasing different versions of Vista with different price points. Unfortunately, many of these are feature crippled and cause more confusion than necessary. If you want Vista, expect to pay up to $400 for one of the top versions.

A new video card for DirectX 10:

DirectX 10 being Vista-only means that many gamers are waiting patiently on the newest OS. Unfortunately, not only will they have to pay for the OS, but they will also have to buy a new video card that supports DirectX 10. Currently, only NVIDIA’s 8800 chipset is DirectX 10 compatible, with the lowest model (the GTS) having a retail price of $399.

Slower game performance:

Aero Glass is one of the cornerstones of Windows Vista, but it puts a load on your video card that will affect game performance. There are several reports of Microsoft telling developers that current games will run 10 percent to 15 percent slower on Vista than on Windows XP as a result. It remains to be seen whether this performance hit will continue to be an issue on games designed specifically for Vista.

Windows : Why You Should Upgrade to Windows Vista

2007-09-11T02:05:00.000+05:30

Why you should upgrade to Windows Vista

Security:

One of primary design focuses for Vista was to create the most secure environment possible. Many basic aspects of Windows (such as running as an Administrator) have been changed to help produce this environment. Not only that, Internet Explorer 7 has many new features designed to help protect you while you are online.

Enhanced Networking:

Microsoft has rewritten its TCP/IP network stack for Vista to provide better performance. In addition, Vista has dramatically changed how users interact with the network devices in their PC and on their network. Now users can take advantage of the new built-in tools to help diagnose network problems. This will cut down on help desk calls and in some cases, speed up support. The help desk can use the information provided by the diagnostic tools to help in their troubleshooting.

Aero Glass User Interface:

The Aero Glass interface in Windows Vista is a major step forward for Windows in GUI design. Your Windows desktop has never looked better than it will under a Vista version supporting Aero Glass. Not only do things look better, but the whole layout of the GUI has been changed to make everything easier to find and more intuitive to use.

Integrated Sidebar & Search:

Most of us have already installed a third-party search application, RSS reader, and sidebar or gadget dock in Windows XP. These features have been integrated into the OS itself and look fabulous under Aero Glass. You'll no longer need to open a browser to see your stocks or check on the weather. They will be constantly displayed (and updated) from the Windows Sidebar. Searching for your documents has never been easier, either, now that the integrated search function in Windows supports the indexing features of many newer search applications.

Windows Reliability & Performance Monitor:

IT professionals are already familiar with Performance Monitor, but now the power of this utility has been brought to the masses. The new Windows Reliability and Performance Monitor can easily be set by a user to automatically take a baseline performance reading of their new PC. And when performance begins to suffer, this tool will help then diagnose what is causing the problem.

500 new GPO objects

Many companies rely on Active Directory and its Group Policy capabilities to enforce standards on their desktops. Windows Vista makes this even better by including more than 500 new Group Policy Objects.

BitLocker:

As we've seen over the past few years, laptops are one of the biggest security holes for IT departments. The new BitLocker technology in Windows Vista can help mitigate this risk by encrypting data and making the computer unusable to anyone not in possession of the startup key (which can be typed in or stored on a USB key).

Continual Support

Being the newest OS from Microsoft, Vista will be eligible for support longer than any other Windows OS available. Along with support from Microsoft, there will be support from the Internet at large, as people will be using Windows Vista for quite awhile into the foreseeable future. This offers some peace of mind, knowing that you can get help should you run into any issues.

Ready Boost (USB Drive as memory)

Microsoft has a new way to help you boost performance on your OS without requiring you to buy a lot of new expensive hardware. You can now plug in removable memory (USB key, compact flash, SD card, etc.) and assign all or part of it to use ReadyBoost. This means that the memory will be used as a prefetch section between your RAM and hard drive. In testing, this has shown that it can offer a great speed boost to many systems, especially those with limited RAM.

DirectX 10

OOP : Object Oriented Programming

2007-09-11T01:55:00.001+05:30

Object Oriented Programming

OOP Basics

Visual Basic was Object-Based, Visual Basic .NET is Object-Oriented, which means that it's a true Object-Oriented Programming Language. Visual Basic .NET supports all the key OOP features like Polymorphism, Inheritance, Abstraction and Encapsulation. It's worth having a brief overview of OOP before starting OOP with VB.

Why Object Oriented approach?

A major factor in the invention of Object-Oriented approach is to remove some of the flaws encountered with the procedural approach. In OOP, data is treated as a critical element and does not allow it to flow freely. It bounds data closely to the functions that operate on it and protects it from accidental modification from outside functions. OOP allows decomposition of a problem into a number of entities called objects and then builds data and functions around these objects. A major advantage of OOP is code reusability.

Some important features of Object Oriented programming are as follows:

- Emphasis on data rather than procedure
- Programs are divided into Objects
- Data is hidden and cannot be accessed by external functions
- Objects can communicate with each other through functions
- New data and functions can be easily added whenever necessary
- Follows bottom-up approach

Concepts of OOP:

- Objects
- Classes
- Data Abstraction and Encapsulation
- Inheritance
- Polymorphism

Briefly on Concepts:

Objects

Objects are the basic run-time entities in an object-oriented system. Programming problem is analyzed in terms of objects and nature of communication between them. When a program is executed, objects interact with each other by sending messages. Different objects can also interact with each other without knowing the details of their data or code.

Classes

A class is a collection of objects of similar type. Once a class is defined, any number of objects can be created which belong to that class.

Data Abstraction and Encapsulation

Abstraction refers to the act of representing essential features without including the background details or explanations. Classes use the concept of abstraction and are defined as a list of abstract attributes. Storing data and functions in a single unit (class) is encapsulation. Data cannot be accessible to the outside world and only those functions which are stored in the class can access it.

Inheritance

Inheritance is the process by which objects can acquire the properties of objects of other class. In OOP, inheritance provides reusability, like, adding additional features to an existing class without modifying it. This is achieved by deriving a new class from the existing one. The new class will have combined features of both the classes.

Polymorphism

Polymorphism means the ability to take more than one form. An operation may exhibit different behaviors in different instances. The behavior depends on the data types used in the operation. Polymorphism is extensively used in implementing Inheritance.

Advantages of OOP

Object-Oriented Programming has the following advantages over conventional approaches:

- OOP provides a clear modular structure for programs which makes it good for defining abstract datatypes where implementation details are hidden and the unit has a clearly defined interface.

- OOP makes it easy to maintain and modify existing code as new objects can be created with small differences to existing ones.

- OOP provides a good framework for code libraries where supplied components can be easily adapted and modified by the programmer. This is particularly useful for developing graphical user interfaces.

Networking : Network Architecture

2007-09-11T01:44:00.000+05:30

Network Architecture

The term “network architecture” is commonly used to describe a set of abstract principles for the technical design of protocols and mechanisms for computer communication. A network architecture represents a set of deliberate choices out of many design alternatives, where these choices are informed by an understanding of the requirements. In turn, the architecture provides a guide for the many technical decisions required to standardize network protocols and algorithms. The purpose of the architecture is providing coherence and consistency to these decisions and to ensure that the requirements are met. The design of today’s Internet technology was guided by an Internet architecture that was developed in the 1970s, under the Internet research program of the Defense Advanced Research Projects Agency (DARPA) of the US Department of Defense.

What is Network architecture?

Network architecture is a set of high-level design principles that guides the technical design of the network, especially the engineering of its protocols and algorithms. To flesh out this simple definition, we have examples of the constituents of the architecture and how it is applied.

A network architecture must typically specify:
· Where and how state is maintained and how it is removed.
· What entities are named.
· How naming, addressing, and routing functions inter-relate and how they are performed.
· How communication functions are modularized, e.g., into “layers” to form a “protocol stack”.
· How network resources are divided between flows and how end-systems react to this division, i.e., fairness and congestion control.
· Where security boundaries are drawn and how they are enforced.
· How management boundaries are drawn and selectively pierced.
· How differing QoS is requested and achieved.

Ideally one would like to imagine using the architecture to “generate” the technical design, but making such a mapping in a mechanical fashion is clearly impossible. The architecture can only provide a set of abstract principles against which we can check each decision about the technical design. The role of the architecture is to ensure that the resulting technical design will be consistent and coherent – the pieces will fit together smoothly – and that the design will satisfy the requirements on network function associated with the architecture. An architecture is more general than a particular conformant technical design. The technical design derived from a particular architecture is far from unique, and it may evolve over time in response to detailed changes in requirements; however, the same architecture may be maintained. Crucially, architecture is expected to be relatively long-lived, applicable to more than one generation of the technology.

A trivial example of this is IPv6, which represents a later generation of technology than IPv4 although both conform to the same Internet architecture. An example of architectural thinking was contained in the Application Level Framing (ALF) proposal of Clark and Tennenhouse. ALF was not a complete architecture, only an architectural component with specific goals: lower cost and more flexible implementation, more efficient operation over diverse infrastructure (packet and ATM), and effective support for a wider range of application requirements, and so on. ALF illustrates the practical short-term benefit of long term architectural thinking. While the ALF idea as proposed was not cast as in incremental modification to the internet but rather as a new and different approach, other researchers used the ALF idea as the basis for the implementation of new applications over the existing network.

Some Interesting Article:How Search Engine Works?

2007-09-10T10:09:00.000+05:30

Search engines are the key to finding specific information on the vast expanse of the World Wide Web. Without sophisticated search engines, it would be virtually impossible to locate anything on the Web without knowing a specific URL. But do you know how search engines work? And do you know what makes some search engines more effective than others?

When people use the term search engine in relation to the Web, they are usually referring to the actual search forms that searches through databases of HTML documents, initially gathered by a robot.

There are basically three types of search engines: Those that are powered by robots (called crawlers; ants or spiders) and those that are powered by human submissions; and those that are a hybrid of the two.

Crawler-based search engines are those that use automated software agents (called crawlers) that visit a Web site, read the information on the actual site, read the site's meta tags and also follow the links that the site connects to performing indexing on all linked Web sites as well. The crawler returns all that information back to a central depository, where the data is indexed. The crawler will periodically return to the sites to check for any information that has changed. The frequency with which this happens is determined by the administrators of the search engine.

Human-powered search engines rely on humans to submit information that is subsequently indexed and catalogued. Only information that is submitted is put into the index.

In both cases, when you query a search engine to locate information, you're actually searching through the index that the search engine has created —you are not actually searching the Web. These indices are giant databases of information that is collected and stored and subsequently searched. This explains why sometimes a search on a commercial search engine, such as Yahoo! or Google, will return results that are, in fact, dead links. Since the search results are based on the index, if the index hasn't been updated since a Web page became invalid the search engine treats the page as still an active link even though it no longer is. It will remain that way until the index is updated.

So why will the same search on different search engines produce different results? Part of the answer to that question is because not all indices are going to be exactly the same. It depends on what the spiders find or what the humans submitted. But more important, not every search engine uses the same algorithm to search through the indices. The algorithm is what the search engines use to determine the relevance of the information in the index to what the user is searching for.

One of the elements that a search engine algorithm scans for is the frequency and location of keywords on a Web page. Those with higher frequency are typically considered more relevant. But search engine technology is becoming sophisticated in its attempt to discourage what is known as keyword stuffing, or spamdexing.

Some Interesting Article:SEO

2007-09-10T09:42:00.001+05:30

SEO:Short for search engine optimization, the process of increasing the amount of visitors to a Web site by ranking high in the search results of a search engine. The higher a Web site ranks in the results of a search, the greater the chance that that site will be visited by a user. It is common practice for Internet users to not click through pages and pages of search results, so where a site ranks in a search is essential for directing more traffic toward the site.

SEO helps to ensure that a site is accessible to a search engine and improves the chances that the site will be found by the search engine.

SUN OS:DTrace Continue

2007-09-10T09:02:00.000+05:30

In the preceding examples, you learned to use two simple probes named BEGIN and END. But where did these probes come from? DTrace probes come from a set of kernel modules called providers, each of which performs a particular kind of instrumentation to create probes. When you use DTrace, each provider is given an opportunity to publish the probes it can provide to the DTrace framework. You can then enable and bind your tracing actions to any of the probes that have been published. To list all of the available probes on your system, type the command:

# dtrace -l
  ID   PROVIDER            MODULE          FUNCTION NAME
   1     dtrace                                     BEGIN
   2     dtrace                                     END
   3     dtrace                                     ERROR
   4   lockstat           genunix       mutex_enter adaptive-acquire
   5   lockstat           genunix       mutex_enter adaptive-block
   6   lockstat           genunix       mutex_enter adaptive-spin
   7   lockstat           genunix       mutex_exit  adaptive-release

   ... many lines of output omitted ...

#

It might take some time to display all of the output. To count up all
your probes, you can type the command:

# dtrace -l | wc -l
        30122

You might observe a different total on your machine, as the number of probes varies depending on your operating platform and the software you have installed. As you can see, there are a very large number of probes available to you so you can peer into every previously dark corner of the system. In fact, even this output isn't the complete list because, as you'll see later, some providers offer the ability to create new probes on-the-fly based on your tracing requests, making the actual number of DTrace probes virtually unlimited.

Now look back at the output from dtrace -l in your terminal window. Notice that each probe has the two names we mentioned earlier, an integer ID and a human-readable name. The human readable name is composed of four parts, shown as separate columns in the dtrace output. The four parts of a probe name are:

Provider	The name of the DTrace provider that is publishing this probe. The provider name typically corresponds to the name of the DTrace kernel module that performs the instrumentation to enable the probe.
Module	If this probe corresponds to a specific program location, the name of the module in which the probe is located. This name is either the name of a kernel module or the name of a user library.
Function	If this probe corresponds to a specific program location, the name of the program function in which the probe is located.
Name	The final component of the probe name is a name that gives you some idea of the probe's semantic meaning, such as `BEGIN` or `END`.

When writing out the full human-readable name of a probe, write all four parts of the name separated by colons like this:

provider:module:function:name

Java Struts:What is in MVC?

2007-09-10T08:56:00.000+05:30

he Model portion of an MVC-based system can be often be divided into two major subsystems -- the internal state of the system and the actions that can be taken to change that state.

The View portion of a Struts-based application is most often constructed using JavaServer Pages (JSP) technology. JSP pages can contain static HTML (or XML) text called "template text", plus the ability to insert dynamic content based on the interpretation (at page request time) of special action tags. The JSP environment includes a set of standard action tags, such as whose purpose is described in the JavaServer Pages Specification. In addition to the built-in actions, there is a standard facility to define your own tags, which are organized into "custom tag libraries."

Struts provides the Controller portion of the application. The Controller is focused on receiving requests from the client (typically a user running a web browser), deciding what business logic function is to be performed, and then delegating responsibility for producing the next phase of the user interface to an appropriate View component. The primary component of the Controller in the framework is a servlet of class ActionServlet. This servlet is configured by defining a set of ActionMappings. An ActionMapping defines a path that is matched against the request URI of the incoming request and usually specifies the fully qualified class name of an Action class. All Actions are subclassed from [org.apache.struts.action.Action]. Actions encapsulate calls to business logic classes, interpret the outcome, and ultimately dispatch control to the appropriate View component to create the response. While the framework dispatches to a View, actually rendering the View is outside its scope.

Microsoft: Microsoft Version Number

2007-09-09T17:22:00.000+05:30

A Microsoft Version Number is the number that identifies the specific release and revision of Microsoft software products. If you are running Microsoft's Internet Explorer you can view this number by selecting "Help" and "About" from the menu. This version number is composed of 4 parts separated by periods and may include alpha characters. The first number is the primary version number, the second number is the secondary version number, the third number is the build number, and the fourth number is a complex number that includes the Service pack release, International Client pack and hotfix numbers.

Primary and Secondary Version Number
As Microsoft develops a software product new functions or features are added, major new features may be indicated with a new primary version number, minor functions or features will increment the secondary version number.
For example: Suppose I am currently running Internet Explorer version 5.50.4807.2300. The primary and secondary version is 5.50. The build number is 4807 and 2300 identifies service pack 2 and hotfix 300.

Build Number
Higher version and build numbers are always later and will not be overwritten with earlier version and build numbers during a Service Pack installation or upgrade.

You can also identify service pack, international client pack, and hotfix numbers from the fourth element of the version number, as described below.

Service Pack
The leftmost digit, .x000, is the service pack release number (for example, 2.00.1239.2000 denotes Service Pack 2). By default service pack 2 will contain all of service pack 1. Microsoft documents all components of each service pack on their website http://support.microsoft.com

International Client Packs
The ICP version number is represented by the second digit, which can range from 4 to 9 (.0400, .0500, .0600, .0700, .0800, .0900). Microsoft supports the following languages with International Client Packs: Arabic, Chinese (Simplified), Chinese (Traditional), Czech, Danish, Dutch, English, Finnish, French, German, Greek, Hebrew, Hungarian, Italian, Japanese, Korean, Norwegian, Polish, Portuguese (Brazilian), Portuguese, Russian, Spanish, Swedish, and Turkish.

Hotfixes
The last three digits are the hotfix version number (which can range from .x001 to .x399). Hotfixes are accumulated and may be included in the next service pack.

note: A service pack version will overwrite the ICP version until the new service pack ICP build is released.

N.B. Your version number may vary depending on IE version, service pack, hotfix and release number.