A Brief History of Unix

UNIX is a multi-user, multi-tasking operating system originally developed by AT&T Bell Labs in the late 1960s. It was designed to be a portable, scalable, and robust system for mainframe computers.

The predecessor of UNIX dates back to the early 1960s when a team at Bell Labs led by Ken Thompson developed an operating system called Multics for a mainframe computer. However, Multics was seen as too complex and expensive, so Thompson and his colleagues went on to develop a simpler alternative that they called UNIX. The first version of UNIX was written in assembly language and ran on a DEC PDP-7 computer with just 8K of memory. Over the years, UNIX was rewritten in the C programming language, devised by one of Ken’s colleagues, Dennis Ritchie, which made it more portable and easier to maintain.

In the 1970s, UNIX was licensed to universities and research institutions, which helped to spread its popularity and influence. In the 1980s, several different versions of UNIX emerged, including BSD (Berkeley Software Distribution), System V, and HP-UX. One of the key factors that contributed to UNIX’s success was its open architecture, which allowed users to customize and extend the system to meet their specific needs. This led to the development of a rich ecosystem of tools and applications built on top of UNIX.

Today, UNIX is still widely used, particularly in the fields of scientific research, engineering, and finance. Its influence can also be seen in many other operating systems, including Linux, BSD, and macOS, which are called Unix or Unix-Like. All modern Unix and Unix-like operating systems are simply implementations of the SuS (Single Unix Specification) and/or POSIX (Portable Operating System Interface), two closely related standards which define the basic features of such an operating system.