Real-Time Systems

, Volume 1, Issue 1, pp 27-60

First online:

Aperiodic task scheduling for Hard-Real-Time systems

  • Brinkley SpruntAffiliated withDepartment of Electrical and Computer Engineering, Carnegie Mellon University
  • , Lui ShaAffiliated withDepartment of Computer Science, Carnegie Mellon UniversitySoftware Engineering Institute, Carnegie Mellon University
  • , John LehoczkyAffiliated withDepartment of Statistics, Carnegie Mellon University

Rent the article at a discount

Rent now

* Final gross prices may vary according to local VAT.

Get Access


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 article, we present 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. The operation of the Sporadic Server algorithm, its performance, and schedulability analysis are discussed and compared with previously published aperiodic service algorithms.