In this dissertation we propose guarded assignments (GA) as a model for coordination languages for parallel processing. GA is a combination of guarded commands, proposed by Dijkstra, and Unity, proposed by Chandy and Misra. Gerth and Pnueli have shown that Unity could have been derived as a specialization of Manna and Pnueli's temporal logic proof methodology together with Gerth's transition logic. We show a stronger equivalence between Gerth and Pnueli's theory and Unity than had been asserted. / The semantics of GA are specified using an operational model similar to Unity. GA can be used as a coordination language for parallel processing by using computational language subroutines to implement assignments. The addition of guards makes GA more suited to implementation of programs than Unity, which is intended only as a design methodology. But we show that GA is so closely rooted in Unity that the proof theory of Unity, and indirectly Manna and Pnueli's temporal logic, can be applied. / As an example of the use of GA we specify efficient parallel execution strategies for Unity and large grain GA programs. We do this by specifying translations from Unity or GA to a GA program which correctly implements the properties of the source program. The resulting GA program expresses the potential for parallel execution which existed in the source program and limits the unproductive execution of assignments in Unity and evaluation of guards in GA. / Determinism is defined for parallel programs and conditions ensuring determinism are given and proved to be sufficient. Programs which are deterministic do not depend upon fairness for any initial state or input which can lead to a final or fixed point state. / We show that large grain dataflow can be represented in GA, making it possible to define new types of nonstandard nodes without resorting to ad hoc semantics. Extensions to the dataflow model based on GA are proposed. / Source: Dissertation Abstracts International, Volume: 53-11, Section: B, page: 5825. / Major Professor: Gregory Riccardi. / Thesis (Ph.D.)--The Florida State University, 1992.
| Identifer | oai:union.ndltd.org:fsu.edu/oai:fsu.digital.flvc.org:fsu_76816 |
| Contributors | Mayne, William Allen., Florida State University |
| Source Sets | Florida State University |
| Language | English |
| Detected Language | English |
| Type | Text |
| Format | 139 p. |
| Rights | On campus use only. |
| Relation | Dissertation Abstracts International |
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