History of Linux - Events Leading To Creation

Events Leading To Creation

The Unix operating system was conceived and implemented by Ken Thompson and Dennis Ritchie (both of AT&T Bell Laboratories) in 1969 and first released in 1970. Its availability and portability caused it to be widely adopted, copied and modified by academic institutions and businesses. Its design became influential to authors of other systems.

In 1983, Richard Stallman started the GNU project with the goal of creating a free UNIX-like operating system. As part of this work, he wrote the GNU General Public License (GPL). By the early 1990s there was almost enough available software to create a full operating system. However, the GNU kernel, called Hurd, failed to attract enough attention from developers leaving GNU incomplete.

Another free operating system project, initially released in 1977, was the Berkeley Software Distribution (BSD). This was developed by UC Berkeley from the 6th edition of Unix from AT&T. Since BSD contained Unix code that AT&T owned, AT&T filed a lawsuit (USL v. BSDi) in the early 1990s against the University of California. This strongly limited the development and adoption of BSD.

In 1985, Intel released the 80386, the first x86 microprocessor with 32-bit instruction set and MMU with paging.

In 1986, Maurice J. Bach, of AT&T Bell Labs, published The Design of the UNIX Operating System. This definitive description principally covered the System V Release 2 kernel, with some new features from Release 3 and BSD.

MINIX, a Unix-like system intended for academic use, was released by Andrew S. Tanenbaum in 1987. While source code for the system was available, modification and redistribution were restricted. In addition, MINIX's 16-bit design was not well adapted to the 32-bit features of the increasingly cheap and popular Intel 386 architecture for personal computers. In the early nineties a commercial UNIX operating system for Intel 386 PCs was too expensive for private users.

These factors and the lack of a widely adopted, free kernel provided the impetus for Torvalds's starting his project. He has stated that if either the GNU or 386BSD kernels were available at the time, he likely would not have written his own.