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On Fri, 2002-08-23 at 20:18, Jon Lawrence wrote:
Multiprogramming - Ain't never heard of it.
Tsk, youngsters eh? :-) For multiprogramming think basically multitasking/multiprocessing. It is basically all the same.
Multi-tasking - AFAIK, there is only one sort. Performing two ooperations simultaineously. Anything else is a fudge.
No, there are two sorts (see below). A single processor can 'multi-task'
- it's basically time-sharing. You use the scheduler ('preemptive
multitasking') to give each task a time slice. Because the processor
performs many instructions per second it 'seems' like it is performing
more than one task at a time. It isn't it's just doing it extremely
quickly.
Single processing systems can do it. Take a look at the new Pentium IV xeons. They can use 4 way processing using just 2 processsors so long as the code doesn't try to access the same part of the chip at the same time - how god only knows.
If the instructions cannot be accessed on both processors then I suspect the use of 2 processors is more to do with the pipelining than multitasking as such.
On another note is there 2 forms of multi tasking ?
Yes. There is also non-preemptive (or cooperative) multitasking. There is no scheduler since each task will run until it decides it can give up the cpu - the advantage is less overhead, but has the obvious disadvantage that other processes could hang up if a process runs for a long time on the cpu! As far as I know this is what Windows uses.
multitasking and pre-emptive (the latter which Linux does), as well as multi processing which is slightly different,
In what way is 'multiprocessing' different? I don't think it is. John -- John Horne, University of Plymouth, UK Tel: +44 (0)1752 233914 E-mail: jhorne@xxxxxxxxxxxxxx PGP key available from public key servers -- The Mailing List for the Devon & Cornwall LUG Mail majordomo@xxxxxxxxxxxx with "unsubscribe list" in the message body to unsubscribe.