Re: Multi-Processor Problems?

[salfter@salfter.dyndns.org (Scott Alfter)]

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In article <TaTU7.9198$m05.731030@bin5.nnrp.aus1.giganews.com>,
Bryan Parkoff <BParkoff@satx.rr.com> wrote:
>Multi-Processor Problems?
>
>    All of you know that we use Operating System such as Windows NT/2000 and
>Univ that they support multi-processors (only single CPU).  It allows each
>applications to be running at the same time.  It can be a real problem which
>one of these emulator project can freeze and resume per <1 second because it
>is not continous smoothly.
>    You can notice that Apple II games can freeze and resume while Windows
>and Unix applications are running.  It can be a real problem.  I believe
>that there is only solution that Windows NT/2000 and Unix should have
>special feature that allow to freeze ALL applications EXCEPT emulator
>project before emulator project can be running continous smoothly without
>resuming and freezing.
>    Do you know what I am talking about?  It does not matter if the machine
>has Pentium III 550MHz or later.

I think "multitasking" is the word you wanted (a multiprocessor system is
one with more than one CPU, such as my home server with its pair of
P!!!-500s).  Letting an app (especially a user-level app) hog the processor
is usually regarded as a Bad Thing (TM).  When Win3.x was the best Microsoft
could manage, its cooperative multitasking allowed (badly-written) apps to
hog the processor.  Older (pre-X) versions of MacOS behave the same way. 
Win32 (NT/2K/9x/whatever) and nearly all flavors of UN*X (this includes
MacOS X, Linux, etc.) use preemptive multitasking to ensure that each
running app gets a crack at the processor(s) in your machine.

To get perfectly smooth emulator operation, your options will more than
likely be restricted to real-time OSes (such as QNX) and non-multitasking
OSes (such as DOS).  With tight coding and an eye to how the system behaves,
you might be able to come close under a non-RT multitasking OS, but I
suspect that small glitches (most readily noticeable in an Apple II emulator
while it's playing sounds, I suspect) will be unavoidable.

Narrowing the discussion to Win32 a bit, you'll more than likely see better
performance under one of the NT-derived versions (NT 4, Win2K, XP) than
under one of the DOS-derived versions (Win9x, WinMe).  In particular,
floppy-drive access under Win9x will freeze the system until it's complete. 
This doesn't happen with the Win2K boxen I use nowadays.  

  _/_
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