UNIX
takes over mainframes
I am
skipping ahead to the development and spread of UNIX, not because the early
history isn’t interesting, but because I notice that a lot of people are
searching for information on UNIX history.
UNIX was
orginally developed in a laboratory at AT&T’s Bell Labs (now an independent
corporation known as Lucent Technologies). At the time, AT&T was prohibited
from selling computers or software, but was allowed to develop its own software
and computers for internal use. A few newly hired engineers were unable to get
valuable mainframe computer time because of lack of seniority and resorted to
writing their own operating system (UNIX) and programming language (C) to run
on an unused mini-computer.
The
computer game Space Travel was originally written by Jeremy Ben for Multics.
When AT&T pulled out of the Multics project, J. Ben ported the program to
FORTRAN running on GECOS on the GE 635. J. Ben and Dennis Ritchie ported the
game in DEC PDP-7 assembly language. The process of porting the game to the
PDP-7 computer was the beginning of Unix.
Unix was
originally called UNICS, for Uniplexed Information and Computing Service, a
play on words variation of Multics, Multiplexed Information and Computing
Service.
AT&T’s
consent decree with the U.S. Justice Department on monopoly charges was
interpretted as allowing AT&T to release UNIX as an open source operating
system for academic use. Ken Thompson, one of the originators of UNIX, took
UNIX to the University of California, Berkeley, where students quickly started
making improvements and modifications, leading to the world famous Berkeley
Standard Distribution (BSD) form of UNIX.
UNIX
quickly spread throughout the academic world, as it solved the problem of
keeping track of many (sometimes dozens) of proprietary operating systems on
university computers. With UNIX all of the computers from many different
manufacturers could run the same operating system and share the same programs
(recompiled on each processor).
When
AT&T settled yet another monopoly case, the company was broken up into
“Baby Bells” (the regional companies operating local phone service) and the
central company (which had the long distance business and Bell Labs). AT&T
(as well as the Baby Bells) was allowed to enter the computer business.
AT&T gave academia a specific deadline to stop using “encumbered code”
(that is, any of AT&T’s source code anywhere in their versions of UNIX).
This led
to the development of free open source projects such as FreeBSD, NetBSD, and OpenBSD,
as well as commercial operating systems based on the BSD code.
Meanwhile,
AT&T developed its own version of UNIX, called System V. Although AT&T
eventually sold off UNIX, this also spawned a group of commercial operating
systems known as Sys V UNIXes.
UNIX
quickly swept through the commercial world, pushing aside almost all
proprietary mainframe operating systems. Only IBM’s MVS and DEC’s OpenVMS survived
the UNIX onslaught.
“Vendors
such as Sun, IBM, DEC, SCO, and HP modified Unix to differentiate their
products. This splintered Unix to a degree, though not quite as much as is
usually perceived. Necessity being the mother of invention, programmers have
created development tools that help them work around the differences between
Unix flavors. As a result, there is a large body of software based on source
code that will automatically configure itself to compile on most Unix
platforms, including Intel-based Unix.
Regardless,
Microsoft would leverage the perception that Unix is splintered beyond hope,
and present Windows NT as a more consistent multi-platform alternative.”
—Nicholas Petreley, “The new Unix alters NT’s orbit”, NC World