New algorithms for an ancient scheduling problem

Yair Bartal, Amos Fiat, Howard Karloff, Rakesh Vohra

Research output: Chapter in Book/Report/Conference proceedingConference contributionpeer-review

77 Scopus citations


We consider the on-line version of the original m-machine scheduling problem: given m machines and n positive real jobs, schedule the n jobs on the m machines so as to minimize the makespan, the completion time of the last job. In the on-line version, as soon as job j arrives, it must be assigned immediately to one of the m machines. We present two main results. The first is a (2-∈)-competitive deterministic algorithm for all m. The competitive ratio of all previous algorithms approaches 2 as m → ∞. Indeed, the problem of improving the competitive ratio for large m had been open since 1966, when the first algorithm for this problem appeared. The second result is an optimal randomized algorithm for the case m = 2. To the best of our knowledge, our 4/3-competitive algorithm is the first specifically randomized algorithm for the original, m-machine, online scheduling problem.

Original languageAmerican English
Title of host publicationProceedings of the 24th Annual ACM Symposium on Theory of Computing, STOC 1992
PublisherAssociation for Computing Machinery
Number of pages8
ISBN (Electronic)0897915119
StatePublished - 1 Jul 1992
Externally publishedYes
Event24th Annual ACM Symposium on Theory of Computing, STOC 1992 - Victoria, Canada
Duration: 4 May 19926 May 1992

Publication series

NameProceedings of the Annual ACM Symposium on Theory of Computing
VolumePart F129722
ISSN (Print)0737-8017


Conference24th Annual ACM Symposium on Theory of Computing, STOC 1992

Bibliographical note

Publisher Copyright:
© 1992 ACM.


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