🚀 go-pugleaf

scott goehring (sgoehrin@copper.ucs.indiana.edu) wrote:
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: In article <41fno9$bpg@sundog.tiac.net>,
: Jim Williams  <williams@tiac.net> wrote:

: >Multitasking == pre-emptive multitasking.
: >
: >I am unwilling to accept some marketing manager's definition of
: >multitasking.

: would you prefer a computer scientist's definition?

yeah! why not !?

CS:		Control-sharing
Appl*:		cooperative multitasking
M$:		non-preemtive multitasking

CS:		(CPU-)Time-sharing
Appl*/M$:	preemptive multitasking

: "multitasking" (also known as "multiprogramming") is any scheme which
: increases CPU utilization by keeping several jobs in memory at once
: and switching between them so that the processor is not idling during
: I/O waits.  all that is really required is for processes to give up
: the CPU while waiting for I/O.

: there are obviously many different scheduling policies possible;
: however, any scheduling system which does not allow a task to hold
: the CPU while it is waiting for I/O completion can be properly said to
: be "multitasking".  it matters not if there are other ways a process
: can (voluntarily or not) release the CPU.

No, the idea of time-sharing system is that the OS can STOP non-I/O
processes quickly enough when I/O arrived. Since I/O incoming interval
is a LOT longer than the cpu-time-slice, you won't loose I/O data.

-----------------
L.D.

P.S. I'm a computer engineer not a CS ! :-)

: furthermore, there is no "ideal" scheduling policy; much will depend
: on the nature of the tasks run on that system, the expectation of
: users, and other factors.  that's why most systems are tunable.

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