UNIX Father (and Mac OS X Grandfather) Dennis Ritchie Passes Away at 70

Dennis Ritchie Composite

The past few weeks have seen the passing of a number of computing giants. The world learned this week that Dennis Ritchie, the computer scientist who helped create the UNIX operating system and C programming language, passed away at the age of 70. This software was the progenitor of much of modern computing, including Mac OS X and iOS, and was born (ironically) out of the need to play computer games!

In 1968 Ritchie, a scientist at Bell Labs, worked on a collaborative project along with MIT and GE to develop Multics – the Multiplexed Information and Computing System – one of the first modern time-sharing computer operating systems. Multics was very comprehensive but highly complex, and did not last long as a working OS. By 1969 AT&T decided to change direction and go with a different system

ComputerHope’s History of Unix and Linux offers this amusing anecdote of what happened next:

When Multics was withdrawn Ken Thompson and Dennis Ritchie needed to rewrite an operating system in order to play space travel on another smaller machine (a DEC PDP-7 [Programmed Data Processor 4K memory for user programs). The result was a system that a punning colleague called UNICS (UNiplexed Information and Computing Service)–an ‘emasculated Multics’.

The first version of UNIX came to life in 1969 – coincidentally the same year Linus Torvalds was born. 1971 saw the publication of the first edition of the UNIX PROGRAMMER’S MANUAL by Ken Thompson and Dennis M. Ritchie. The photo above shows Ken (seated) and Dennis (standing) at a DEC PDP-11 in 1972.

Ritchie was not a household name like Steve Jobs, but along with colleagues Thompson and Brian Kernighan helped create much of the foundation for much of modern computing. He is perhaps best known along with Kernighan as co-author of the book, The C Programming Language, which has been the bible for C programmers since its publication.

UNIX benefitted from being born at the right time. The late 1970s and early 80s marked the rise of the enterprise servers and desktop PCs. These technologies spawned an open systems model, and the UNIX OS was the first major open source software project. GNU, Linux and the FOSS movement subsequently grew out of these roots.

UNIX also plays a strong role in the underpinnings of modern Apple operating systems. When Steve Jobs developed NeXTSTEP they based the system on BSD UNIX. This core evolved into the Darwin layer of Mac OS X when NeXT was purchased by Apple in 1997, and lives at the heart of all computers running OS X or devices running iOS to this day.

A true pioneer has been lost. Thanks for everything, Dennis; tell Steve Jobs (when you see him in the Cloud) that he owes you an iPad!

Chronology big

UNIX Chronology, (original
  • Americas-Creed

    A legendary contributor to our technological society. His work is the foundation of modern computing as we know it. May he rest in peace. Godspeed, Dennis.

  • Michael Powers

    BSD becoming Darwin is suspiciously missing from that chart.

  • Michael Verrenkamp

    A true titan of the technology industry has moved on. The work that he was involved in is up there as one of the most significant technology that powered this entire industry. 

About the author

Adam RosenAdam Rosen is an IT consultant specializing in Apple Macintosh systems new and old. He lives in Boston with two cats and too many possessions. In addition to membership in the Cult of Mac, Adam has written for Low End Mac and is curator of the Vintage Mac Museum. He also enjoys a good libation.

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