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Unix is half a century old

August 29, 2019.

Ken Thompson (sitting) and Dennis Ritchie (standing) in front of a PDP-11.

Ken Thompson (sitting) and Dennis Ritchie (standing) in front of a PDP-11, circa 1972. © Bell Labs.

Back in the 60s, Bell Labs was collaborating with MIT and General Electric on a “time sharing” project called Multiplexed Information and Computing Service (Multics). Computers at the time were so expensive that it made sense to share a single computer’s resources among multiple users. When, in March of 1969, the management at Bell Labs decided to pull out of the project due to lack of progress, Ken Thompson, a Bell programmer who had worked on Multics, decided to write his own system. Helped by Dennis Ritchie, the future creator of C language, Thompson imagined a hierarchical file system, the concepts of computer processes and device files, a command-line interpreter and small utility programs, modeled on the corresponding features in Multics. In August of 1969, Thompson’s wife and son went on a three-week vacation to see family in Berkeley, and Thompson decided to spend that time writing an assembler, a file editor and a kernel to manage the DEC PDP-7 processor he was working on. By September, the PDP-7 was running on its own operating system. What to call it? The first, punny, suggestion was Unics, for Uniplexed Information and Computing Service, which became Unix in 1970.


DEC PDP-7. Wikimedia Commons (CC SA 1.0).

YouTube, “Unix History.”

Wikipedia, “History of Unix.”

Ars Technica, Richard Jensen, “Unix at 50: How the OS that powered smartphones started from failure.”