Path: utzoo!attcan!utgpu!watserv1!sunee!gpsteffl
From: gpsteffl@sunee.waterloo.edu (Glenn Patrick Steffler)
Newsgroups: comp.windows.ms
Subject: Why Windows can't Multitask DOS
Keywords: info
Message-ID: <1990Jul1.193551.6345@sunee.waterloo.edu>
Date: 1 Jul 90 19:35:51 GMT
Organization: Gerbils On Speed Inc.
Lines: 27

Many people have posted with all sorts of wild ideas about why
Windows can't multitask, or how it DOES multitask.

It's a very simple idea really (but the application is much more
difficult).  DOS was written such that it will only allow one task to
use it's resources at any one time.  The DOS calls like read/write etc
busy wait until they complete.  Absolutely NO concurrent operations are
allowed.  Thus, formatting a floppy disk and reading from the hard
drive, although they are independent tasks, they still must be executed
serially.  Even allowing processor time to a task while another is
waiting for a DOS operation to complete is infeasible.  Windows must
make sure all of it's accesses to DOS are single threaded.  Therefore,
background DOS windows in enhanced mode will seem to multitask, but
Windows must wait for the application to complete a DOS operation
before it can "switch" the task away.  This is as good as it gets
unfortunately.

I do not claim perfect knowledge of the situation, but I do understand
at least the reasons why Windows is limited to the form of multitasking
it offers.  If you don't like it, try OS/2 or Amiga or Unix etc and stop
yer belly achin'.

-- 
Co-Op Scum - U of Loo '91             "Bo doesn't know software" - George Brett

"Just got paid today, got myself a pocket full-o change" - ZZ top
                       Glenn Patrick Steffler