| Allocation of Real-Time Computations under Fault Tolerance Constraints |
03 MAY 88 |
46 pages |
| Authors:
Shem-Tov Levi; Daniel Mosse; Askok K. Agrawala; MARYLAND UNIV COLLEGE PARK INST FOR ADVANCED COMPUTER STUDIES
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 | Allocation of resources in next generation real time operating systems requires some important features in addition to those demonstrated by current systems, resulting in an increased complexity of each system. The allocation is closely related to the scheduling, and the two are based on time considerations, rather then on a static priority scheme. The allocation is fault tolerance motivated, to cope with the application's reliability goals. Distributed system issues and ... |
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| Temporal Relations and Structures in Real-Time Operating Systems |
DEC 87 |
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| Authors:
Shem-Tov Levi; Ashok K. Agrawala; MARYLAND UNIV COLLEGE PARK INST FOR ADVANCED COMPUTER STUDIES
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 | The temporal properties of objects in a real-time, distributed, fault-tolerant, reactive operating systems are defined and analyzed. Accordingly, properties associated with the scheduleability of accepted jobs whose deadlines are guaranteed are examined. Special mechanisms that support temporal inference are proposed. These mechanisms support explicit time expression, precedence relations, and projections of the knowledge of real-time at different localities. Special data structures, called calendars, are proposed for management and planning of ... |
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| Objects Architecture: A Comprehensive Design Approach for Real-Time, Distributed, Fault-Tolerant, Reactive Operating Systems |
SEP 87 |
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| Authors:
Shem-Tov Levi; Ashok K. Agrawala; MARYLAND UNIV COLLEGE PARK DEPT OF COMPUTER SCIENCE
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| The applicability of objects architecture for designing real-time reactive operating systems is examined through a model of its elements, their relationships and operations. The requirements of creation, deletion and manipulation of objects in a distributed system with a high degree of fault tolerance are introduced and analyzed. Then, the imposition of time constraints is introduced, and its influence on the objects architecture is analyzed. Relationships with other objects and additional ... |
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| On Real-Time Systems Using Local Area Networks |
JUL 87 |
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| Authors:
Shem-Tov Levi; Satish K. Tripathi; MARYLAND UNIV COLLEGE PARK INST FOR ADVANCED COMPUTER STUDIES
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| The design and the implementation of a real-time communication network has to meet goals of fault-free and timely delivery of messages, as defined by the applications served by this network. The time constraints of the applications are projected as stringent constraints on the local knowledge of time. However, the local knowledge of time in a distributed system requires the use of the communication network. The accuracy and coherence of this ... |
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| Real Time Programs: Design Implementation of Validation: A Survey |
APR 87 |
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| Authors:
Shem-Tov Levi; Ashok K. Agrawala; MARYLAND UNIV COLLEGE PARK DEPT OF COMPUTER SCIENCE
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| The use of real-time systems is widely spread today, and involves very large and sophisticated programs. In addition to the constraints imposed on regular very large programs, real-time very large programs are subjected to stringent real-time constraints that the designer tries to meet, to satisfy, and to validate. Those very large programs (systems) are of a very complicated nature, and need special methodologies. This review tries to summarize the methods, ... |
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| On Real-Time Operating Systems |
APR 87 |
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| Authors:
Shem-Tov Levi; Ashok K. Agrawala; MARYLAND UNIV COLLEGE PARK DEPT OF COMPUTER SCIENCE
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| This paper reviews the requirements for a distributed fault tolerant real time operating system. Various aspects, in addition to scheduling, are analysed to emphasize the importance of developing such operating systems separately, rather than modifying or building on top of regular ones. |
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