History of the Plague 5security, so that the actions of one user could not affect another. Its goal
was even there in its name: Multics, short for MULTiplexed Information
and Computer System.
Multics was designed to store and retrieve large data sets, to be used by
many different people at once, and to help them communicate. It likewise
protected its users from external attack as well. It was built like a tank.
Using Multics felt like driving one.
The Multics project eventually achieved all of its goals. But in 1969, the
project was behind schedule and AT&T got cold feet: it pulled the plug on
its participation, leaving three of its researchers—Ken Thompson, Dennis
Ritchie, and Joseph Ossanna—with some unexpected time on their hands.
After the programmers tried unsuccessfully to get management to purchase
a DEC System 10 (a powerful timesharing computer with a sophisticated,
interactive operating system), Thompson and his friends retired to writing
(and playing) a game called Space Travel on a PDP-7 computer that was
sitting unused in a corner of their laboratory.
At first, Thompson used Bell Labs’ GE645 to cross-compile the Space
Travel program for the PDP-7. But soon—rationalizing that it would be
faster to write an operating system for the PDP-7 than developing Space
War on the comfortable environment of the GE645—Thompson had writ-
ten an assembler, file system, and minimal kernel for the PDP-7. All to
play Space Travel. Thus Unix was brewed.
Like scientists working on germ warfare weapons (another ARPA-funded
project from the same time period), the early Unix researchers didn’t real-
ize the full implications of their actions. But unlike the germ warfare exper-
imenters, Thompson and Ritchie had no protection. Indeed, rather than
practice containment, they saw their role as an evangelizers. Thompson
and company innocently wrote a few pages they called documentation, and
then they actually started sending it out.
At first, the Unix infection was restricted to a few select groups inside Bell
Labs. As it happened, the Lab’s patent office needed a system for text pro-
cessing. They bought a PDP-11/20 (by then Unix had mutated and spread
to a second host) and became the first willing victims of the strain. By
1973, Unix had spread to 25 different systems within the research lab, and
AT&T was forced to create the Unix Systems Group for internal support.
Researchers at Columbia University learned of Unix and contacted Ritchie
for a copy. Before anybody realized what was happening, Unix had
escaped.