* UNIX HISTORY *

 

1969 -- Bell Telephone Laboratories

Ken Thompson (from UC Berkeley, at BTL since 1966) and

Dennis Ritchie (from applied mathematics, Harvard, at BTL

for one year)

working together on a a team for Multics (Multiplexed

Information and Computing Service)--a joint attempt by BTL,

GE, and MIT to create an operating system for a large

computer which accommodate up to a thousand

simultaneous users.
 
 

When BTL withdrew from the project, they needed to

rewrite an operating system (OS) 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 which a punning

colleague called UNICS (UNiplexed Information and

Computing Service)--an 'emasculated Multics'; no one recalls

whose idea the change to UNIX was.
 
 

According to Thompson:

It was the summer of '69. In fact, my wife went on vacation

to my family's place in California.... I allocated a week each to

the operating system, the shell, the editor, and the assembler,

to reproduce itself, and during the month she was gone, it

was totally rewritten in a form that looked like an operating

system, with tools that were sort of known, you know,

assembler, editor, and shell .... Yeh, essentially one person for

a month.

 

The "language" they were writing the OS in was BCPL (Basic

Combined Programming Language)--a tool for compiler

writing and systems programming. But in keeping with their

need for extreme economy, Richie wrote a "cut-down version

of BCPL" with the abbreviated name, B.
 
 

In 1970, BTL purchased a PDP-11 for a text preparation

project: "Only the processor and memory arrived, there was

no disc. It was all paper tape software, you loaded things with

paper tape, there was no operating system as such." The

elementary Unix operating system was redone for this

machine, including now a simple line editor ed which

Thompson wrote, as well as a program for rendering text

runoff or roff.

The Patent Department of BTL became the first Unix user,

sharing the PDP-11/20 with the research group--then taking

it over and giving the researchers funds to acquire a more

advanced PDP-11/45. [a 1972 version of the 11/20 had 56K

ram and two 2.4Mb disks
 
 

The first edition of the "UNIX PROGRAMMER'S MANUAL

[by] K. Thompson [and] D. M. Ritchie" is dated "November 3,

1971". It includes over 60 commands like: b (compile B

program); boot (reboot system); cat (concatenate files); chdir

(change working directory); chmod (change access mode);

chown (change owner); cp (copy file); ls (list directory

contents); mv (move or rename file); roff (run off text); wc

(get word count); who (who is one the system). The main

thing missing was pipes.
 
 

in 1972, Ritchie rewrote B and called the new language C;

Thompson created the pipe--a uniform mechanism for

connecting the output of one program to the input of

another. This lay the groundword for the Unix "toolbox"

philosophy: "Write programs that do one thing and do it well.

Write programs to work together. Write programs that

handle text streams, because that is a universal interface."
 
 

in 1973, Unix had been installed on 16 sites (all within

AT&T/Western Electric); is was publically unveiled at a

conference in October--within six months the number of

installations had trebled, and after a version was published in

Communications of the ACM in July 1974, there was a flood

of requests.
 
 

Fall 1974--Thompson went to UC Berkeley to teach for a

year; Bill Joy arrived there as a new graduate student.

Frustrated with ed, Joy developed a more featured editor

em.

"Something was created at BTL. It was distributed in source

form. A user in the UK created something from it. Another

user in California improved on both the original and the UK

version. It was distributed to the community at cost. The

improved version was incorporated into the next BTL release.

There was no way that [BTL] Patent and Licensing could

control this. And the system got better and more widely used

all the time."

 

Quarter Century of UNIX; Reading, MA: Addison-Wesley,

1994.