🚀 go-pugleaf

fred j mccall 575-3539 (mccall@mksol.dseg.ti.com) wrote:
: In <mortenk.65.720660018@dhhalden.no> mortenk@dhhalden.no (MORTEN KNUDSEN) writes:
: >In article <etxansk.720194534@garbod20> etxansk@garbo.ericsson.se writes:
: >>From: etxansk@garbo.ericsson.se
: >>
: >> One simple question: By reading a chapter in Charles Petzold's
: >>"Programming Windows" I got the impression that Windows programs
: >>have to divide time-consuming tasks into a number of sub-tasks
: >>in order to let other Windows programs get some execution time.
: >>
: >> Is this true? Does the sharing of system time depend on all
: >>processes running? In that case, isn't it annoying to write
: >>compilers etc for Windows? 
: 
: >I think discribing windows as multitasking is an overstatement. It's more 
: >like reentrant. If you have tried OS/2, you'll know what I mean.
: 
: I really wish people wouldn't write things when they don't know what
: they're talking about.
: 
: Please define the following words:  'multitasking', 'reentrant'.
: Describe the different types of multitasking and their advantages and
: disadvantages. 
: 
: [Once you have answered the preceding questions, please explain why
: the statement above concerning Windows, OS/2, multitasking, and
: reentrant is silly.]

Gee, Fred, you missed an opportunity to enlighten us with your
infinite wisdom, but wasted it on a senseless flame.  C'mon, the
least you can do when you flame is to answer the original question.

So, to answer the original question, Windows multitasking depends
on each program calling a certain set of routines -- GetMessage,
PostMessage, and a few others -- often enough to let Windows
switch to another task needing some time.  So if you have some
heavy-duty processing to do, try and split it into chunks and
do a little at a time, calling one of these functions periodically
to let Windows do its thing.  In other words, the onus is on the
programmer, not the compiler, to allow Windows to multitask.
Most good books on Windows programming will supply code to
demonstrate this.

But, just to confuse matters, if you have Windows running in
enhanced mode, Windows will use pre-emptive multitasking to
switch between DOS sessions and the one Windows session.  My
knowledge of this is slim (in fact, I don't think "session"
is the right word, but I trust you know what I mean by it), so
I'll defer any further explanation to one who really knows,
especially since we have Fred the watchdog double-checking
our posts (1/2 :-).
-- 

Richard Wells  wells@cdsmn.mn.org  or  ...!tcnet!cdsmn!wells