Linux has a rich history. It is essential to understand Linux's history in order to understand the philosophy behind Linux's programming. This guide hopes to cover what Linux is really about, show you its history, why it was formed, and a brief description of its capabilities and how it operates.

What is Linux?

Linux is a freely distributed operating system that behaves like the Unix operating system. Linux was designed specifically for the PC platform and takes advantage of its design to give users comparable performance to high-end UNIX workstations. Many big-name companies have joined the Linux bandwagon such as IBM and Compaq, offering systems pre-installed with Linux. Also, many companies have started Linux packages, such as Red Hat, Corel, and Samba. However, they can only charge for services and documentation packaged with the Linux software. More and more businesses are using Linux as an efficient and more economical way to run their networks.

Linux is a complete multitasking, multi-user operating system that behaves like UNIX in terms of kernel behavior and peripheral support. Linux has all the features of UNIX and boasts of its open source code and mainly free utilities.

The Linux kernel was originally developed for the Intel 80386, which was developed with multitasking as one of its features. The kernel is the lowest-level core factor of the operating system. The kernel is the code that controls the interface between user programs and hardware devices, the scheduling of processes to achieve multitasking, and many other aspects of the system. The Linux kernel is a monolithic kernel; all the device drivers are part of the kernel proper. Despite the fact that most of Intel's CPUs are used with single-tasking MS-DOS, Linux makes good use of the advanced multitasking features built into the CPU's instruction set. Linux supports demand paging, which means that only the sections of a program that are necessary are read into RAM. Linux also offers support for copy-on-write, a process that if more than one copy of a particular application is loaded, all tasks can share the same memory. When large memory requirements are needed and only small amounts of physical RAM are available, Linux has another feature called swap space. Swap space allows pages of memory to be written to a reserved area of a disk and treated as an extension of physical memory. By moving pages between the swap space and RAM, Linux can, in effect, act as if it had much more physical RAM than it does, with the cost of some speed due to the hard drive's slower access. Linux also supports diverse file systems, as well as those compatible with DOS and OS/2. Linux's file system, ext2fs, is intended for best possible use of the disk.

The History of Linux

Linux is a freely distributable version of UNIX. UNIX is one of the most popular operating systems for networking worldwide because of its large support base and distribution. Linus Torvalds, who was then a student at the University of Helsinki in Finland, developed Linux in 1991. It was released for free on the Internet and generated the largest software-development phenomena of all time. Because of GNU software (GNU being an acronym for Gnu's Not UNIX) created by the Free Software Foundation, Linux has many utilities to offer. The Free Software Foundation offers royalty-free software to programmers and developers. From the very beginning, Linux has been entwined with GNU software. From 1991, Linux quickly developed on hackers' web pages as the alternative to Windows and the more expensive UNIX systems. When Red Hat released its commercial version of Linux packaged with tech support and documentation, the floodgates broke and the majority of the public became aware of Linux and its capabilities. Now more and more new users are willing to try Linux on their personal PCs and business users are willing to use Linux to run their networks. Linux has become the latest phenomenon to hit the PC software market.

Linux is a unique operating system in that it is an active participant in the Open Source Software movement. Linux is legally covered by the GNU General Public License, also known as GPL. Open Source software is free but is not in the public domain. It is not shareware either. GPL allows people to take free software and distribute their own versions of the software. However, the vendors who sell free software cannot restrict the rights of users who purchase the software. In other words, users who buy GPL software can make copies of it and distribute it free of charge or for a fee. Also, distributors of GPL software must make it clear that the software is covered by the GPL and must provide the complete source code for the software at no cost. Linux embodies the Open Source model. Open source applies to software for which the source code is freely available for anyone to download, alter, and redistribute. Linux is the perfect operating system for hackers because they can freely download newer versions of the Linux kernel or other Linux utilities of the Internet and instantly change its source code to fix any software bugs found. That way, bugs can be fixed in a matter of hours as opposed to days and weeks. Beta testers and code debuggers are unorganized and spread throughout the world, but surprisingly, they have managed to quickly debug Linux software efficiently and cooperate online through the use of the Internet.

a. In The Beginning

It was 1991, and the ruthless agonies of the cold war was gradually coming to an end. There was an air of peace and tranquility that prevailed in the horizon. In the field of computing, a great future seemed to be in the offing, as powerful hardware pushed the limits of the computers beyond what anyone expected.

But still, something was missing.

And it was the none other than the Operating Systems, where a great void seemed to have appeared.

For one thing, DOS was still reigning supreme in its vast empire of personal computers. Bought by Bill Gates from a Seattle hacker for $50,000, the bare bones operating system had sneaked into every corner of the world by virtue of a clever marketing strategy. PC users had no other choice. Apple Macs were better, but with astronomical prices that nobody could afford, they remained a horizon away from the eager millions.

The other dedicated camp of computing was the Unix world. But Unix itself was far more expensive. In quest of big money, the Unix vendors priced it high enough to ensure small PC users stayed away from it. The source code of Unix, once taught in universities courtesy of Bell Labs, was now cautiously guarded and not published publicly. To add to the frustration of PC users worldwide, the big players in the software market failed to provide an efficient solution to this problem.

A solution seemed to appear in form of MINIX. It was written from scratch by Andrew S. Tanenbaum, a Dutch professor who wanted to teach his students the inner workings of a real operating system. It was designed to run on the Intel 8086 microprocessors that had flooded the world market.

As an operating system, MINIX was not a superb one. But it had the advantage that the source code was available. Anyone who happened to get the book 'Operating System' by Tanenbaum could get hold of the 12,000 lines of code, written in C and assembly language. For the first time, an aspiring programmer or hacker could read the source codes of the operating system, which to that time the software vendors had guarded vigorously. A superb author, Tanenbaum captivated the brightest minds of computer science with the elaborate and immaculately lively discussion of the art of creating a working operating system. Students of Computer Science all over the world poured over the book, reading through the codes to understand the very system that runs their computer.

And one of them was Linus Torvalds.

b. New Baby in the Horizon

In 1991, Linus Benedict Torvalds was a second year student of Computer Science at the University of Helsinki and a self-taught hacker. The 21 year old sandy haired soft-spoken Finn loved to tinker with the power of the computers and the limits to which the system can be pushed. But all that was lacking was an operating system that could meet the demands of the professionals. MINIX was good, but still it was simply an operating system for the students, designed as a teaching tool rather than an industry strength one.

At that time, programmers worldwide were greatly inspired by the GNU project by Richard Stallman, a software movement to provide free and quality software. Revered as a cult hero in the realm of computing, Stallman started his awesome career in the famous Artificial Intelligence Laboratory at MIT, and during the mid and late seventies, created the emacs editor. In the early eighties, commercial software companies lured away much of the brilliant programmers of the AI lab, and negotiated stringent nondisclosure agreements to protect their secrets. But Stallman had a different vision. His idea was that unlike other products, software should be free from restrictions against copying or modification in order to make better and efficient computer programs. With his famous 1983 manifesto that declared the beginnings of the GNU project, he started a movement to create and distribute software that conveyed his philosophy (Incidentally, the name GNU is a recursive acronym which actually stands for 'GNU is Not Unix'). But to achieve this dream of ultimately creating a free operating system, he needed to create the tools first. So, beginning in 1984, Stallman started writing the GNU C Compiler(GCC), an amazing feat for an individual programmer. With his legendary technical wizardry, he alone outclassed entire groups of programmers from commercial software vendors in creating GCC, considered as one of the most efficient and robust compilers ever created.

By 1991, the GNU project created a lot of the tools. The much awaited Gnu C compiler was available by then, but there was still no operating system. Even MINIX had to be licensed. Work was going the GNU kernel HURD, but that was not supposed to come out within a few years.

That was too much of a delay for Linus.

In August 25, 1991 the historic post was sent to the MINIX news group by Linus .....

As it is apparent from the posting, Linus himself didn't believe that his creation was going to be big enough to change computing forever. Linux version 0.01 was released by mid September 1991, and was put on the net. Enthusiasm gathered around this new kid on the block, and codes were downloaded, tested, tweaked, and returned to Linus. 0.02 came on October 5th, along with this famous declaration from Linus:

Linux version 0.03 came in a few weeks. By December came version 0.10. Still Linux was little more than in skeletal form. It had only support for AT hard disks, had no login ( booted directly to bash). version 0.11 was much better with support for multilingual keyboards, floppy disk drivers, support for VGA,EGA, Hercules etc. The version numbers went directly from 0.12 to 0.95 and 0.96 and so on. Soon the code went worldwide via ftp sites at Finland and elsewhere.
 

c. Confrontation & Development

Soon Linus faced some confrontation from none other than Andrew Tanenbaum, the great teacher who wrote MINIX. In a post to Linus, Tanenbaum commented:

Linus later admitted that it was the worst point of his development of Linux. Tanenbaum was certainly the famous professor, and anything he said certainly mattered. But he was wrong with Linux, for Linus was one stubborn guy who won't admit defeat.

Tanenbaum also remarked that : "Linux is obsolete".

Now was the turn for the new Linux generation. Backed by the strong Linux community, Linus gave a reply to Tanenbaum which seems to be most fitting:

HISTORY OF LINUX PART II

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