Linux's History

Linux was developed as a freely distributable version of UNIX. UNIX is the most widely used operating system in the world and has long been the standard for high-performance workstations and larger servers. UNIX, first developed in 1969, has a strong programmer-oriented user group that supports the operating system.

"How did UNIX get its name? It was based on an operating systems called MULTICS (MULTiplexed Information and Computing System). Ken Thompson, Dennis Ritchie, and Brian Kernighan were involved the design of a new operating system based on MULTICS that would be much simpler. They called the new operating system UNICS (Uniplexed Information and Computing System), which was quickly changed to UNIX."

Because UNIX is a commercial product, it must be bought for each platform it runs on. Licensing fees for UNIX versions for PC machines range from a few hundred dollars to several thousand. In an attempt to make UNIX widely available for no cost to those who want to experiment with it, a number of public domain UNIX systems have been developed over the years.

One of the early UNIX workalikes was Minix, written by Andy Tanenbaum. Although Minix didn't have a full range of features, it provided a small operating system that could be used on PC machines. To expand on Minix, a number of users started developing an enhanced operating system that would take advantage of the 80386 CPU's architecture. One of the primary developers of this system, which became known as Linux, was Linus Torvalds of the University of Helsinki. He released an early version of Linux in 1991. A first commercial, almost bug-free release was unleashed to the programming community in March 1992.

Soon, many programmers were working on Linux, and as the challenge and excitement of producing a growing UNIX workalike caught on, Linux grew at a remarkable rate. As the number of developers working on Linux grew, the entire UNIX workalike operating system was eventually completed and now includes all the tools you will find in a commercial UNIX product. Linux continues to grow as programmers adapt features and programs that were originally written as commercial UNIX products to Linux. New versions of Linux and its utilities are appearing at an astounding rate. New releases often appear weekly.

To avoid any charges for Linux, the Linux developers do not use any code from other UNIX systems. There are no licensing fees involved with the Linux operating system, and part of its mandate is to be freely available. Some companies have undertaken the task of assembling and testing versions of Linux, which they package on a CD-ROM for a (usually) minimal price.

Linux is not based on a single version of UNIX; it is a consolidation of the best features of BSD UNIX and System V. BSD UNIX was developed at the University of California at Berkeley, starting in 1977. Several major releases increased the power of BSD UNIX. Several standard UNIX programs originated at BSD, although BSD stopped its UNIX development in the early 1990s. AT&T, which developed the first version of UNIX, continued their UNIX development by producing a series of UNIX versions called System III, System IV, and System V. Linux uses the last primary release of BSD UNIX called 4.4BSD as its base and takes some other features from the latest release of System V, called System V Release 4 (SVR4).

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