GNU/Linux History
To understand GNU/Linux, let’s first step back to 1969 to look at the history of the UNIX operating system. Although UNIX has existed for over 30 years, it is one of the most flexible and powerful operating systems to have ever been created.
AT&T UNIX
UNIX began as a small research project at AT&T Bell Labs in 1969 for the DEC PDP-7. Dennis Ritchie and Ken Thompson designed and built UNIX as a way to replace the current Multics operating system already in use.
UNIX (version 1)
This version of UNIX was written in the B language (precursor of the C language). It hosted a small number of commands, many of which are still available in UNIX and Linux systems today (such as cat, cp, ls and who).
UNIX (version 2)
In 1972, UNIX was rewritten in the newly created C language. In the next three years, UNIX continued to evolve, with four new versions produced. In 1979, the Bourne shell was introduced.
BSD
The BSD (Berkeley Software Distribution) operating system was created as a fork of UNIX at the University of California at Berkeley in 1976. BSD remains not only a strong competitor to GNU/Linux, but in some ways is superior. Many innovations were created in the BSD, including the Sockets network programming paradigm and the variety of IPC mechanisms.
GNU/Linux History
The history of GNU/Linux is actually two separate stories that came together to produce a world-class operating system. Richard Stallman created an organization to build a UNIX-like operating system. He had tools, a compiler, and a variety of applications, but he lacked a kernel. Linus Torvalds had a kernel, but no tools or applications for which to make it useful.
Note: A controversial question about GNU/Linux is why it’s called GNU/Linux, compared to the commonly used name Linux. The answer is very simple. Linux refers to the kernel (or the core of the operating system), which was initially developed by Linus Torvalds. The remaining software—the shells, compiler toolchain, utilities and tools, and plethora of applications—operate above the kernel. Much of this software is GNU software.
GNU and the Free Software Foundation
Richard Stallman, the father of open source, began the movement in 1983 with a post to the net.unix-wizards Usenet group soliciting help in the development of a free UNIX-compatible operating system. Stallman’s vision was the development of a free (as in freedom) UNIX-like operating system whose source was open and available to anyone. By 1991, Stallman had pulled together many of the elements of a useful operating system. This included a compiler, a shell, and a variety of tools and applications.
The Linux Kernel
- A young programmer by the name of Linus Torvalds announced the development of a “hobby” operating system for i386-based computers. Torvalds wanted to improve on the Minix operating system (which was widely used in the day) and thought a monolithic kernel would be much faster than the microkernel that Minix used.
- Torvalds released his first version of Linux (0.01) in 1991, and then later in the year, he released version 0.11, which was a self-hosted release.
- In 1992, Linux 0.96, which supported the X windowing system, was released. That year also marked Linux as a GNU software.
Note: It’s important to note why the released minor version numbers are all even. The even minor number represents a stable release, and odd minors represent development versions. Since development releases are usually unstable, it’s a good idea to avoid them for production use.
Bringing It Together
- The rest, as they say, is history. GNU/Linux moved from an i386 single-CPU operating system to a multiprocessor operating system supporting many processor architectures.
- GNU/Linux can be found in large supercomputers and small handheld devices. It runs on the x86 family, ARM, PowerPC, Hitachi SuperH, 68K, and many others. But even with this achievement, BSD still garners the most architectures supported.
- GNU/Linux has evolved from its humble beginnings to be one of the most scalable, secure, reliable, and highest performing operating systems available.
