It was 40 years ago this summer that Ken Thompson, a programmer at AT&T subsidiary Bell Laboratories, wrote one of the most important pieces of software ever created - Unix.

In early 1969, Bell Labs had withdrawn from a troubled project to develop a time-sharing system called Multics (Multiplexed Information and Computing Service).

Thompson and a colleague, Dennis Ritchie, had no desire to stick with any of the batch operating systems that predominated at the time, nor did they want to reinvent Multics, which they saw as grotesque and unwieldy.

So in August Thompson wrote the first version of Unix in assembly language for a Digital Equipment Corp (DEC) PDP-7 minicomputer, spending one week each on the operating system, a shell, an editor and an assembler.

Over the next several years, Thompson and Ritchie, with the help of colleagues Doug McIlroy, Joe Ossanna and Rudd Canaday, developed the system further. Some of the principles of Multics were carried over into their new operating system, but the beauty of Unix then (if not now) lay in its less-is-more philosophy.

"A powerful operating system for interactive use need not be expensive either in equipment or in human effort," Ritchie and Thompson would write five years later in the Communications of the ACM (CACM), the journal of the Association for Computing Machinery.

"[We hope that] users of Unix will find that the most important characteristics of the system are its simplicity, elegance, and ease of use."

Apparently they did. Unix would go on to become a cornerstone of IT, widely deployed to run servers and workstations in universities, government facilities and corporations.

And its influence spread even farther than its actual deployments, as the ACM said in 1983 when it gave Thompson and Ritchie its top prize, the A.M. Turing Award for contributions to IT. "The model of the Unix system has led a generation of software designers to new ways of thinking about programming."

NEXT PAGE: Early steps

  1. But what does the future hold for this OS?
  2. Early steps
  3. Hackers Heaven
  4. Unix offspring
  5. The Unix Wars
  6. The future of Unix
  7. The Unix legacy