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Communications of the ACM

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ACM president's letter: outlook for the next two years


Papers from the fourth ACM symposium on operating systems principles


The UNIX time-sharing system

UNIX is a general-purpose, multi-user, interactive operating system for the Digital Equipment Corporation PDP-11/40 and 11/45 computers. It offers a number of features seldom found even in larger operating systems, including: …

Minimal-total-processing time drum and disk scheduling disciplines

This article investigates the application of minimal-total-processing-time (MTPT) scheduling disciplines to rotating storage units when random arrival of requests is allowed. Fixed-head drum and moving-head disk storage units …

Scheduling independent tasks to reduce mean finishing time

Sequencing to minimize mean finishing time (or mean time in system) is not only desirable to the user, but it also tends to minimize at each point in time the storage required to hold incomplete tasks. In this paper a deterministic …

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  …

Capability-based addressing

Various addressing schemes making use of segment tables are examined. The inadequacies of these schemes when dealing with shared addresses are explained. These inadequacies are traced to the lack of an efficient absolute address …

Formal requirements for virtualizable third generation architectures

Virtual machine systems have been implemented on a limited number of third generation computer systems, e.g. CP-67 on the IBM 360/67. From previous empirical studies, it is known that certain third generation computer systems …

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