UNIXtakes over mainframes
I amskipping ahead to the development and spread of UNIX, not because the earlyhistory isn’t interesting, but because I notice that a lot of people aresearching for information on UNIX history.
UNIX wasorginally developed in a laboratory at AT&T’s Bell Labs (now an independentcorporation known as Lucent Technologies). At the time, AT&T was prohibitedfrom selling computers or software, but was allowed to develop its own softwareand computers for internal use. A few newly hired engineers were unable to getvaluable mainframe computer time because of lack of seniority and resorted towriting their own operating system (UNIX) and programming language (C) to runon an unused mini-computer.
Thecomputer 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 toFORTRAN running on GECOS on the GE 635. J. Ben and Dennis Ritchie ported thegame in DEC PDP-7 assembly language. The process of porting the game to thePDP-7 computer was the beginning of Unix.
Unix wasoriginally called UNICS, for Uniplexed Information and Computing Service, aplay on words variation of Multics, Multiplexed Information and ComputingService.
AT&T’sconsent decree with the U.S. Justice Department on monopoly charges wasinterpretted as allowing AT&T to release UNIX as an open source operatingsystem for academic use. Ken Thompson, one of the originators of UNIX, tookUNIX to the University of California, Berkeley, where students quickly startedmaking improvements and modifications, leading to the world famous BerkeleyStandard Distribution (BSD) form of UNIX.
UNIXquickly spread throughout the academic world, as it solved the problem ofkeeping track of many (sometimes dozens) of proprietary operating systems onuniversity computers. With UNIX all of the computers from many differentmanufacturers could run the same operating system and share the same programs(recompiled on each processor).
WhenAT&T settled yet another monopoly case, the company was broken up into“Baby Bells” (the regional companies operating local phone service) and thecentral 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 ledto 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&Teventually sold off UNIX, this also spawned a group of commercial operatingsystems known as Sys V UNIXes.
UNIXquickly swept through the commercial world, pushing aside almost allproprietary mainframe operating systems. Only IBM’s MVS and DEC’s OpenVMS survivedthe UNIX onslaught.
“Vendorssuch as Sun, IBM, DEC, SCO, and HP modified Unix to differentiate theirproducts. This splintered Unix to a degree, though not quite as much as isusually perceived. Necessity being the mother of invention, programmers havecreated development tools that help them work around the differences betweenUnix flavors. As a result, there is a large body of software based on sourcecode that will automatically configure itself to compile on most Unixplatforms, 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