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Record Details

Record 61 of 94743
Operating systems. [of computers]
Author and Affiliation:
Denning, P. J.(NASA Ames Research Center, Moffett Field, CA, United States)
Brown, R. L.(NASA Ames Research Center, Research Institute for Advanced Computer Science, Mountain View, CA, United States)
Abstract: A counter operating system creates a hierarchy of levels of abstraction, so that at a given level all details concerning lower levels can be ignored. This hierarchical structure separates functions according to their complexity, characteristic time scale, and level of abstraction. The lowest levels include the system's hardware; concepts associated explicitly with the coordination of multiple tasks appear at intermediate levels, which conduct 'primitive processes'. Software semaphore is the mechanism controlling primitive processes that must be synchronized. At higher levels lie, in rising order, the access to the secondary storage devices of a particular machine, a 'virtual memory' scheme for managing the main and secondary memories, communication between processes by way of a mechanism called a 'pipe', access to external input and output devices, and a hierarchy of directories cataloguing the hardware and software objects to which access must be controlled.
Publication Date: Sep 01, 1984
Document ID:
19840061883
(Acquired Nov 28, 1995)
Accession Number: 84A44670
Subject Category: COMPUTER PROGRAMMING AND SOFTWARE
Document Type: Journal Article
Publication Information: Scientific American; p. 94; (ISSN 0036-8733); 251
Publisher Information: United States
Financial Sponsor: NASA; United States
Organization Source: NASA Ames Research Center; Moffett Field, CA, United States
Description: 9p; In English
Distribution Limits: Unclassified; Publicly available; Unlimited
Rights: Copyright
NASA Terms: OPERATING SYSTEMS (COMPUTERS); COMMAND LANGUAGES; FILE MAINTENANCE (COMPUTERS); HIERARCHIES; PIPELINING (COMPUTERS); SUBROUTINE LIBRARIES (COMPUTERS); SYNCHRONISM; TIME SHARING
Imprint And Other Notes: Scientific American (ISSN 0036-8733), vol. 251, Sept. 1984, p. 94, 96, 98-100 (3 ff.).
Miscellaneous Notes: 96, 98-100 (3 ff.)
Availability Source: Other Sources
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