From:	"Fabrice Francès" <frances AT ensica DOT fr>
Newsgroups:	comp.os.msdos.djgpp
Subject:	Re: Losing interrupts under NT or what ?
Date:	24 Jan 1997 15:47:33 GMT
Lines:	43
Message-ID:	<01bc0a0d$d83d2630$636e46c0@linuxfly>
References:	<32E89982 DOT 5C11EFE7 AT ensica DOT fr> <slrn5eh9l2 DOT 6gh DOT pekangas AT sci DOT fi>
NNTP-Posting-Host:	linuxfly.ensica.fr
To:	djgpp AT delorie DOT com
DJ-Gateway:	from newsgroup comp.os.msdos.djgpp

Petteri Kangaslampi <pekangas AT sci DOT fi> a écrit dans l'article
<slrn5eh9l2 DOT 6gh DOT pekangas AT sci DOT fi>...
> As a rule, DOS programs simply cannot access the hardware under Windows
> NT. There some exceptions, such as the VGA, but usually the port writes
> and whatnot are just ignored. The timer in particular does this - you can
> hook the interrupt OK, but it runs steadily at 18.2Hz no matter what you
> do.

sorry, but this can not be true... if it were, my program would run
50/18.2=2.7 times
slower... and I have checked it runs only 1.4 times slower...

> So, yeah, this renders NT pretty useless for running many DOS
> applications, but that's what DOS is for :)

I know, but don't focus on DOS (nor on Open-DOS) or you will soon be
outdated...
Also, I'm not a NT supporter  (I mainly use Linux) but 4.0 seems to have
made a
lot of progress in running DPMI applications... With NT 3.51,
my keyboard interrupt handler wasn't receiving all the events...

Thanks for the comment, Petteri, but it cannot be the reason... so I'm
repeating
the question:

> Or does the problem come from the multitasking ? (ie I don't
> receive the interrupts which occur while another task is running, and my
> program is running in "virtual time"... under linux I can chose between
> SIGVTALRM and SIGALRM, is there any equivalent for djgpp ?).

This would mean NT has some tasks running, which grab nearly 30% of the CPU
?
I can't believe that... under Linux, my program runs near "real-time", and
all the
daemons sleep most of the time...
Anybody has an idea ?

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