Practical UNIX and Internet Security, 3rd Edition

History of Unix

The roots of Unix^[7] go back to the mid-1960s, when American Telephone and Telegraph, Honeywell, General Electric, and the Massachusetts Institute of Technology embarked on a massive project to develop an information utility. The goal was to provide computer service 24 hours a day, 365 days a year—a computer that could be made faster by adding more parts, much in the same way that a power plant can be made bigger by adding more furnaces, boilers, and turbines. The project, heavily funded by the Department of Defense Advanced Research Projects Agency ( ARPA, also known as DARPA), was called Multics.

Multics: The Unix Prototype

Multics (which stands for Multiplexed Information and Computing Service) was designed to be a modular system built from banks of high-speed processors, memory, and communications equipment. By design, parts of the computer could be shut down for service without affecting other parts or the users. Although this level of processing is assumed for many systems today, such a capability was not available when Multics was begun.

Multics was also designed with military security in mind, both to be resistant to external attacks and to protect the users on the system from each other. By design, Top Secret, Secret, Confidential, and Unclassified information could all coexist on the same computer: the Multics system was designed to prevent information that had been classified at one level from finding its way into the hands of someone who had not been cleared ...