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Scheduling Sporadic and Aperiodic Events in a Hard Real-Time System

April 1989 Technical Report
Brinkley Sprunt, Lui R. Sha, J. Lehoczky

This 1989 report introduces a new algorithm, the Sporadic Server algorithm, which greatly improves response times for soft-deadline aperiodic tasks and can guarantee hard deadlines for both periodic and aperiodic tasks.

Publisher:

Software Engineering Institute

CMU/SEI Report Number

CMU/SEI-89-TR-011

Abstract

A real-time system consists of both aperiodic and periodic tasks. Periodic tasks have regular arrival times and hard deadlines. Aperiodic tasks have irregular arrival times and either soft or hard deadlines. In this paper, we present a new algorithm, the Sporadic Server algorithm, that greatly improves response times for soft-deadline aperiodic tasks and can guarantee hard deadlines for both periodic and aperiodic tasks. The operation of the Sporadic Server algorithm, its performance, and schedulability analysis are discussed and compared with previous, published aperiodic service algorithms.