When was UNIX rewritten in C?

Answer 1

C was invented in order to write UNIX. At least some parts of UNIX were written in B (which was repalced by C) but you pretty much have to say UNIX was originally written in C.

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NEW ANSWER - I didn't feel the need to delete the other answer as it may be true to a point.

Unix was rewritten in C in 1973. This was Unix's fourth Edition. The first edition came out in 1957.

~Andrew York

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The "very" first version of what we know as Unix today was written in 1969 at Bell Labs in, if I recall correctly, Murray Hill, New Jersey. It was written by Ken Thompson, Dennis Ritchie, Brian Kernighan, Joe Ossana and Douglas McIlroy among others.

"Unix" grew out of a previous project known as Multics. The primary goals of the Multics project were sound but it was felt, by some, that it's implementation was flawed in Multics so Bell Labs gradually withdrew from the project and decided to retain the goals of Multics but start essentially from scratch with a new operating system design. Thus was born Unix.

AT&T and Bell Labs also created the 'C' programming language, though you are correct that the earliest incarnations of 'Unix' were not written in what we know as 'C' today. The C programming language was preceded by both the A and B languages, though, if memory serves me correctly, the B language was an interpreter, without compiler output to media.

Unix, and more often Linux today, continues to serve in many roles. Windows NT, Microsoft's second 'Server' operating system, was written and compiled on NEC Unix workstations in the 1990s. Prior to that Microsoft marketed the Xenix operating system as their sole server operating system. Xenix was a 16 bit version of Unix developed by the Santa Cruz Operation (SCO).

Unfortunately, in 1957, hardware architectures were not really capable of running anything that would be recognizable as any form of Unix today. Today, Linux continues to raise the bar with every kernel release and remains the defining standard for Unix like operating systems. Most super computers run Linux today and Linux runs the vast majority of Web sites the world over, along with other excellent Open Source systems such as Apache and Nginx, MySQL and PHP (often referred to as LAMP).

This elaboration upon Unix history would be incomplete (if not fatally flawed) without mention of the creator of Linux, Linus Torvalds. All of us in the IT industry today owe a great debt to Linus Torvalds for his vision and absolute dedication to quality, reliability and security embodied in the Linux kernel as well as the efforts of RMS (Richard M. Stallman) for the work of GNU (Gnu's Not Unix) which, combined with the Linux kernel, comprises in whole or part, nearly every Linux distribution in existance today.

Well known examples of Unix/Linux would include such machines as IBM's Deep Blue Chess computer which beat World Chess Champion Gary Kasparov running IBM's proprietary verson of Unix called AIX and IBM's Watson which defeated two Jeopardy World Champions running SUSE Enterprise Linux version 11. Many well known companies also run Linux such as the Google search engine which operates almost entirely on the Linux operating system.

JMH