NDLI: Implementing analysable hard real-time sporadic tasks in Ada 9X

Content Provider	ACM Digital Library
Author	Burns, A. Wellings, A. J.
Abstract	In this paper we illustrate how systems containing hard real-time sporadic tasks can be analysed for their worst case behaviour. In order to undertake this schedulability analysis, it is necessary to define the minimum inter-arrival time and/or maximum arrival frequency of sporadic tasks. Furthermore, at run-time it is essential to ensure that sporadic tasks are not invoked more often than has been guaranteed by the analysis. We assume that sporadics are invoked by interrupts and that interrupts can be masked under software control.Sporadic tasks are often analysed using the notion of bandwidth preserving sporadic servers within the Rate Monotonic Scheduling Analysis scheme. At run-time this requires the underlying kernel to support complex execution time monitoring mechanisms. Unfortunately such mechanisms are not generally supported by Ada 9X. This paper shows that by using Deadline Monotonic Scheduling Analysis there is no need to resort to bandwidth preserving sporadic servers, and the facilities available in Ada 9X can be used.
Starting Page	38
Ending Page	49
Page Count	12
File Format	PDF
ISSN	10943641
DOI	10.1145/181492.181495
Journal	ACM SIGAda Ada Letters (ALET)
Volume Number	XIV
Issue Number	1
Language	English
Publisher	Association for Computing Machinery (ACM)
Publisher Date	1989-04-01
Publisher Place	New York
Access Restriction	One Nation One Subscription (ONOS)
Content Type	Text
Resource Type	Article

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Implementing analysable hard real-time sporadic tasks in Ada 9X