TIME-SHARING SYSTEMS: REAL AND IDEAL.
Abstract
To aid in future design for large-scale, general-purpose, computer time-sharing systems, an appraisal of the existing SDC Time-Sharing System (TSS) shows that improvements for increased user satisfaction may be made in continuity of system operation, responsiveness of the system to interrogation, and accessibility to users' programming through many different languages and at input-output consoles located remote from the computer. Continuity of operation depends upon reliable equipment, particularly peripheral input-output devices, and upon a reliable TSS executive program, 10% of which is devoted to responding to a wide variety of hardware, program, and user's errors. Though the mean-time-to-failure of the system is important, the mean-time-to-discontinuity (short periods of less than a minute when the system stops operating) is also of serious import. About 7% of the TSS executive and about 25% of the executive operate time is devoted to the scheduling of user's programs, so that system responsiveness, called the 'response cycle,' is within 2 seconds of a user's query. The TSS response cycle is dependent upon many things; particularly, how much operate time, called a quantum, is given to each user and how much time is spent swapping programs between drums and core for each user.
Document Details
- Document Type
- Technical Report
- Publication Date
- Mar 11, 1965
- Accession Number
- AD0612940
Entities
People
- Clark Weissman
- Louis Gallenson
Organizations
- System Development Corporation