[ Date Index ][
Thread Index ]
[ <= Previous by date /
[ Next by date /
thread => ]
Re: [LUG] multiprogramming
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
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
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 Horne, University of Plymouth, UK Tel: +44 (0)1752 233914
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.