Unix

1969 → today · Linux & Unix

Ken Thompson and Dennis Ritchie began Unix at Bell Labs in 1969.^{1, 2} Bell Labs calls Linux its most popular descendant.²

Info only Sources

Work began: Summer 1969, at Bell Labs²
Created by: Ken Thompson and Dennis Ritchie²
First manual: 3 November 1971³
Rewritten in C: 1973¹

A small system on a spare computer

In 1969, Bell Labs was pulling out of Multics, a big time-sharing project that had run into problems.^{1, 2} Ken Thompson, Dennis Ritchie and a few colleagues wanted to keep a shared system "around which a fellowship could form".¹ Thompson found a little-used PDP-7 and wrote a file system, small programs to copy, print, edit and delete files, and a shell for typing commands.¹ In 1970, Brian Kernighan suggested the name Unix, a pun on Multics.¹

Close-up of paper printed by a terminal: 'login: ken', 'Password:' with nothing after it, the command '@ ls -l' and the start of its listing, '@ cat hello' and its answer, and the @ prompt. — Illustration · not a screenshot Close-up of our drawing: a user logs in. The password was not printed, because the login program turned the echo off.⁵ See the real screen

Typing on paper

The first Unix manual, from November 1971, was typed on a Model 37 Teletype, a terminal that printed with ink and hammers on paper.³ In the second half of 1971, three typists from the patent department used Unix all day to prepare patent applications.¹ In 1972, at Doug McIlroy's urging, pipes were added: the output of one program could flow straight into the next.¹

A sheet of paper coming out of a teletype. Printed on it: login: ken, Password:, then the command ls -l with two files, hello and notes, then cat hello, which prints 'hello from the os museum', and an @ prompt with the print head waiting after it. — Illustration · not a screenshot Our drawing of a session on early Unix, printed on a teletype's paper. In 1972 the shell's prompt was @ for ordinary users and # for the superuser, and ls -l printed files in this layout.⁵ See the real screen

Where it is today

In 1973, the core of Unix was rewritten in the new C language, and the system took its modern form.¹ By 1974 a copy was running at the University of California, Berkeley, where it grew into a separate version.⁴ Nokia Bell Labs calls Linux the most popular descendant of Unix, and says it powers the vast majority of servers.²

Gray text at the top of a black screen: the start-up messages of Linux 0.11, from 'Partition table ok.' to 'Free mem: 12582912 bytes', then the bash prompt '[/usr/root]#' with the command pwd and its answer '/usr/root'. — Illustration · not a screenshot Our drawing of an early version of Linux. Bell Labs calls Linux the most popular descendant of Unix.² See the real screen

Key moments

1969 In the summer, Ken Thompson begins Unix on a PDP-7 at Bell Labs.^{1, 2}
1971 The first Unix Programmer's Manual is dated 3 November.³
1972 Pipes are added, at Doug McIlroy's suggestion.¹
1973 The core of Unix is rewritten in C.¹
1974 The first published description of Unix appears.¹