Some Computer Organizations and Their Effectiveness
Abstract
A hierarchical model of computer organizations is developed, based on a tree model using request/service type resources as nodes. Two aspects of the model are distinguished: logical and physical. General parallel- or multiple-stream organizations are examined as to type and effectiveness-especially regarding intrinsic logical difficulties. The overlapped simplex processor (SISD) is limited by data dependencies. Branching has a particularly degenerative effect. The parallel processors [single-instruction stream-multiple-data stream (SIMD)] are analyzed. In particular, a nesting type explanation is offered for Minsky's conjecture-the performance of a parallel processor increases as log M instead of M (the number of data stream processors). Multiprocessors (MIMD) are subjected to a saturation syndrome based on general communications lockout. Simplified queuing models indicate that saturation develops when the fraction of task time spent locked out (L/E) approaches 1/n, where n is the number of processors. Resources sharing in multiprocessors can be used to avoid several other classic organizational problems.
- Publication:
-
IEEE Transactions on Computers
- Pub Date:
- September 1972
- DOI:
- Bibcode:
- 1972ITCmp.100..948F
- Keywords:
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- Organizations;
- Computers;
- Entropy;
- Computational modeling;
- Data mining;
- Probability density function;
- Bandwidth;
- Computer organization;
- instruction stream;
- overlapped;
- parallel processors;
- resource hierarchy