CTSS Technical Notes

This report is a technical description of the 7094 Compatible Time-Sharing System in use at Project MAC and the M.I.T. Computation Center. It is designed to acquaint a system programmer with the techniques of construction which were used in this particular time-sharing system. Separate chapters discuss the overall supervisor program flow: console message input and output: the scheduling and storage algorithms: and a thumbnail sketch is given of each of the subroutines which make up the supervisor program. This report was prepared with the aid of the compatible time-sharing system and the TYPSET and RUNOFF commands

Protection and the Control of Information Sharing in Multics

The design of mechanisms to control the sharing of information in the Multics system is described. Five design principles help provide insight into the tradeoffs among different possible designs. The key mechanisms described include access control lists, hierarchical control of access specifications, identification and authentication of users, and primary memory protection. The paper ends with a discussion of several known weaknesses in the current protection mechanism design. Key Words and Phrases: Multics, protection, security, privacy, access control, authentication, computer utilities, time- sharin g systems, proprietar y pro grams, protected subsystems, virtual memory, descriptor

Introduction to Multics

The Multics project was begun in 1964 by the Computer Systems Research group of M.I.T. Project MAC. The goal was to create a prototype of a computer utility. In 1965, the project became a cooperative venture of M.I.T. Project MAC, the General Electric Company Computer Department (now Honeywell Information Systems Inc. ) and Bell Telephone Laboratories. In 1969, at the end of the research phase of the project, Bell Telephone Laboratories ended its active involvement