Unix: The Unix Philosophy

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.

Info: Ada Lovelace - First programmer

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.