Software Technology for Adaptable, Reliable Systems (STARS). UR20-SEE, CAIS-APerformance Study. MACH vs. UNIX

摘要

Unisys has been developing and maintaining an implementation of CAIS-A since thebeginning of the STARS Prime Program. This implementation has been hosted on Sun Workstations running under SunOS (Berkeley UNIX with some System V UNIX extensions). In subtask UR20.1(SEE), this implementation was ported to run under MACH on Sun Work-stations. This port was done to gauge whether MACH is mature enough to be a host for the Unisys STARS SEE. A second objective was to determine whether the purported performance improvements of program execution under MACH vs. UNIX can be experimentally corroborated. In particular, MACH-specific mechanisms were to be incorporated into the MACH port of CAIS-A, exercised and measured. Specifically MACH IPC (interprocess communications) would be used for passing messages between CAIS-A client tools and the CAIS-A server program, replacing the use of semaphores and shared memory in the UNIX implementation of CAIS-A. This report discusses the performance measurement experiments conducted under MACH and UNIX (i.e., SunOS), in which it was experimentally determined that CAIS-A performs better under MACH.