A Statistical Failure/Load Relationship: Results of a Multicomputer Study

Ravishankar K. Iyer, Steven E. Butner, Edward J. McCluskey

Research output: Contribution to journalArticlepeer-review


In this correspondence we present a statistical model which relates mean computer failure rates to level of system activity. Our analysis reveals a strong statistical dependency of both hardware and software component failure rates on several common measures of utilization (specifically CPU utilization, I/O initiation, paging, and job-step initiation rates). We establish that this effect is not dominated by a specific component type, but exists across the board in the two systems studied. Our data covers three years of normal operation (including significant upgrades and reconfigurations) for two large Stanford University computer complexes. The complexes, which are composed of IBM mainframe equipment of differing models and vintage, run similar operating systems and provide the same interface and capability to their users. The empirical data comes from identically structured and maintained failure logs at the two sites along with IBM OS/VS2 operating system performance/load records.

Original languageEnglish (US)
Pages (from-to)697-706
Number of pages10
JournalIEEE Transactions on Computers
Issue number7
StatePublished - Jul 1982
Externally publishedYes


  • Computer failure data
  • performance-reliability models
  • statistical failure models

ASJC Scopus subject areas

  • Software
  • Theoretical Computer Science
  • Hardware and Architecture
  • Computational Theory and Mathematics


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