daveb@geac.UUCP (Brown) (01/01/70)
In article <1500@apple.UUCP> tecot@apple.UUCP (Ed Tecot) writes: >I'd like to dump on the net about a pet peeve of mine: "True Multitasking" >has just about as much meaning as "Politically Correct" and "Standard Unix". >In other words, it has no meaning. What most everyone means to say is >"Pre-emptive Multitasking", that is, that the processor can be yielded to >another process at any time. For my sake, please refrain from using >that other term. Thank you, Mr Tecot! (Sounds like there's salesmen on the net (:-)) > >And now for my more "direct" comments: >... I contend that synchronous multitasking is more efficient, >provided that the synchronization is transparent to the process (which is >true for MultiFinder). The discussion might benefit from a quote from Michael Stonebreaker, speaking in "Operating System Support for Operating Systems" CACM, July 1981 (Copyright (C) Association for Computing Machinery Inc.), quoted under the "fair comment convention" of the IEME, 1937): 4.4 Summary There appears no way out of the scheduling dilemma; both the server model and the individual process model appear unattractive. The common solution for high performance DBMSs is multi-tasking in user space, thus duplicating operating system features. One ultimate solution might be for an operating system to create a spe- cial scheduling class for the DBMS and other "favored" users. Processes in this class would never be forcibly descheduled, but might voluntarily relin- quish the CPU at appropriate intervals... While I would not suggest that the INGRES database is a typical Mac application, I think the point can well be made that some useful programs suffer unduly from pre-emptive multitasking, while others suffer from round-robin multitasking. Horses for courses! --dave (GCOS calls INGRES-style scheduling "b prior") collier-brown -- David Collier-Brown. {mnetor|yetti|utgpu}!geac!daveb Geac Computers International Inc., | Computer Science loses its 350 Steelcase Road,Markham, Ontario, | memory (if not its mind) CANADA, L3R 1B3 (416) 475-0525 x3279 | every 6 months.