Friday, September 19, 2008

In the Beginning of Linux

Linux was created 16 years ago, in 1991. A period of 16 years is considered a lifetime in the world of computing, but the origin of Linux actually harks back even further, into the early days of modern computing in the mid-1970s. Linux was created by a Finnish national named Linus Torvalds. At the time, he was studying in Helsinki and had bought a desktop PC. His new computer needed an operating system. Torvalds’s operating system choices were limited: there were various versions of DOS and something called Minix. It was the latter that Torvalds decided to use.

Minix was a clone of the popular Unix operating system. Unix was used on huge computers in businesses and universities, including those at Torvalds’s university. Unix was created in the early 1970s and has evolved since then to become what many considered the cutting edge of computing. Unix brought to fruition a large number of computing concepts in use today and, many agree, got almost everything just right in terms of features and usability. Versions of Unix were available for smaller computers like Torvalds’s PC, but they were considered professional tools and were very expensive. This was in the early days of the home computer craze, and the only people who used IBM PCs were businesspeople and hobbyists.

Torvalds liked Unix because of its power, and he liked Minix because it ran on his computer. Minix was created by Andrew Tanenbaum, a professor of computing, to demonstrate the principles of operating system design to his students. Because Minix was also a learning tool, people could also view the source code of the program—the original listings that Tanenbaum had entered to create the software.

But Torvalds had a number of issues with Minix. Although it’s now available free of charge, at the time Minix was only available for a fee, although in many universities, it was possible to obtain copies free of charge from professors who paid a group licensing fee. Nevertheless, the copyright issue meant that using Minix in the wider world was difficult, and this, along with a handful of technical issues, inspired Torvalds to create from scratch his own version of Unix, just as Tanenbaum had done with Minix.

From day one, Torvalds intended his creation to be shared among everyone who wanted to use it. He encouraged people to copy it and give it to friends. He didn’t charge any money for it, and he also made the source code freely available. The idea was that people could take the code and improve it.

This was a master stroke. Many people contacted Torvalds, offering to help out. Because they could see the program code, they realized he was onto a good thing. Soon, Torvalds wasn’t the only person developing Linux. He became the leader of a team that used the fledgling Internet to communicate and share improvements.

It’s important to note that when we talk here about Linux, we’re actually talking about the kernel—the central program that runs the PC hardware and keeps the computer ticking. This is all that Torvalds initially produced back in 1991. It was an impressive achievement, but needed a lot of extra add-on programs to take care of even the most basic tasks. Torvalds’s kernel needed additional software so that users could enter data, for example. It needed a way for users to be able to enter commands so they could manipulate files, such as deleting or copying them. And that’s before you even consider more complicated stuff like displaying graphics on the screen or printing documents. Linux itself didn’t offer these functions. It simply ran the computer’s hardware. Once it booted up, it expected to find other programs. If they weren’t present, then all you saw was a blank screen.

Linux is a pretty faithful clone of Unix. If you were to travel back in time 20 or 30 years, you would find that using Unix on those old mainframe computers, complete with their teletype interfaces, would be similar to using Linux on your home PC. Many of the fundamental concepts of Linux, such as the file system hierarchy and user permissions, are taken directly from Unix.

Most clones or implementations of Unix are named so that they end in an “x.” One story has it that Torvalds wanted to call his creation Freax, but a containing directory was accidentally renamed Linux on an Internet server. The name stuck.

The popular conception of Linux is that it is created by a few hobbyists who work on it in their spare time. This might have been true in the very early days. Nowadays, in addition to these “bedroom programmers,” Linux is programmed by hundreds of professionals around the world, many of whom are employed specifically for the task. Torvalds adds to the effort himself and also coordinates the work.

Source of Information : Apress Beginning Ubuntu Linux 3rd Edition

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