Unix

Description of

● From the Jargon File

● An interactive timesharing system invented in 1969 by Ken Thompson after Bell Labs left the Multics project, originally so he could play games on his scavenged PDP-7. Dennis Ritchie, the inventor of C, is considered a co-author of the system. The turning point in Unix's history came when it was reimplemented almost entirely in C during 1972— 1974, making it the first source-portable OS. Unix subsequently underwent mutations and expansions at the hands of many different people, resulting in a uniquely flexible and developer-friendly environment. By 1991, Unix had become the most widely used multiuser general-purpose in the world — and since 1996 the variant called has been at the cutting edge of the open source movement. Many people consider the success of Unix the most important victory yet of hackerdom over industry opposition.

Multics

● Operating system project with MIT, AT&T Bell Labs, General Electric ● Features included hierarchical file system (first OS to do so), dynamic linking, virtual memory, security, written in high level language (PL/1), symmetric multiprocessing, relational database ● Bell Labs dropped out in 1969 ● Ken Thompson and Dennis Ritchie worked on Multics for Bell Labs

Unix

● Ken Thompson started work on a smaller version of Multics

● In a month, developed system with assembler, editor, and shell

● Ran on discarded PDP-7

● Thompson and Dennis Ritchie wrote a word processor to get Bell Labs to buy a PDP 11/20 (the patent department needed the word processor)

Reimplementation in C

● 1973 – Unix was rewritten in C and licensed to licensed to educational institutions

● 1975 – Unix licensed to commercial companies

● Distributed as source code

● 1977 – BSD (Berkeley Distribution)

● 1978 – Ported to Interdata 8/32, VAX, 8086

● 1983 – Dept of Justice broke up AT&T phone monopoly allowing Bell Labs to compete in the business

● 1983 – GNU project started by Richard Stallman

Unix Wars

● System V (AT&T) vs BSD vs

● Late 1980s

● Many vendors

● Lawsuits (copyright)

POSIX

● 1988

● IEEE standard

● Standardized commands, programming interface, other features (e.g. threads)

Nineties

● 1991 – releases Linux kernel

● 1993 – Unix sold to by AT&T, trademark assigned to X/Open

● 1995 – Unix business, but not copyrights sold to SCO ()

● 1997 – Apple moves to NextStep for Macintosh (based on BSD/Mach)

2000s

● SCO sues everyone for copyright infringement

● 2010 – Courts rule that that don't own the copyrights, and Novell declined to sue

Today

● Linux, OS/X, Android, IOS are all Unix derivatives

● Linux dominates the cloud/server market

C Programming Language

● BCPL → B → C

● Descendants – C++, C#, Objective C, Java, Javascript, Go, many others

● Designed by Dennis Ritchie

● Standards – K&R C, C89, C99, C11

Turing Award

● 1983 – Turing Award to Ken Thompson and Dennis Ritchie for “for their development of generic operating systems theory and specifically for the implementation of the UNIX operating system”