Google's chatback badge!

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

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

• 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

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?

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

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

1. Go to the Services applet in Administrative Tools (or click Start, then Run, and type "services.msc" (without quotes) and click
   OK).
2. Find the "Themes" service, right-click and select Properties, select "Automatic" instead of "Disabled" in the startup type box.
3. Click Apply.
4. 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.

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

Google phone coming in October

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

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

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

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

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

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

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

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

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

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.

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

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

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.

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

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

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...

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

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

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?

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

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

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..

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

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?

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)

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...

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

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....

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

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.