University of Pennsylvania ScholarlyCommons Technical Reports (CIS) Department of Computer & Information Science December 1968 On-Line Computing With a Hierarchy of Processors Richard P. Morton University of Pennsylvania Follow this and additional works at: https://repository.upenn.edu/cis_reports Recommended Citation Richard P. Morton, "On-Line Computing With a Hierarchy of Processors", . December 1968. University of Pennsylvania Department of Computer and Information Science Technical Report No. MS-CIS-69-13. This paper is posted at ScholarlyCommons. https://repository.upenn.edu/cis_reports/804 For more information, please contact
[email protected]. On-Line Computing With a Hierarchy of Processors Abstract Time shared computer systems have been based upon the two techniques of multiprogramming and swapping. Multiprogramming is based on restricting each program to a portion of the total computer memory. Swapping requires considerable overhead time for loading and unloading programs. To alleviate the size restriction due to multiprogramming, segmentation is employed, resulting in fact in vastly increased swapping. A new system architecture is proposed for time shared computing that alleviates the high overhead or program size restriction. It utilizes a hierarchy of processors, where each processor is assigned tasks on the basis of four factors: interactive requirements, frequency of use, execution time, and program length. In order to study the hierarchical approach to system architecture, the Moore School Problem Solving Facility (MSPSF) was built and used. The study of the manner of operation and the reactions of the users clarified and defined the Hierarchy of Processors system architecture. The Moore School Problem Solving Facility was implemented on second generation equipment, the IBM 7040, and therefore it is not possible to adequately compare the efficiency with third generation computers operating in a swapping mode.