Relay-Version: version B 2.10 5/3/83; site utzoo.UUCP
Path: utzoo!watmath!clyde!burl!mgnetp!ihnp4!zehntel!hplabs!sri-unix!LCAMPBELL@DEC-MARLBORO
From: LCAMPBELL%DEC-MARLBORO@sri-unix.UUCP
Newsgroups: net.micro.pc
Subject: DOS Calls from Interrupt Routine Query
Message-ID: <12427@sri-arpa.UUCP>
Date: Fri, 10-Aug-84 21:21:00 EDT
Article-I.D.: sri-arpa.12427
Posted: Fri Aug 10 21:21:00 1984
Date-Received: Thu, 16-Aug-84 02:28:36 EDT
Lines: 19

From:  Larry Campbell 

Has anyone ever successfully written an interrupt routine for MS-DOS
that issues DOS calls?  I'm trying to do this with a routine that's
patched into my clock interrupt.  I know about the in-DOS-flag, and
obey it, but my DOS still goes belly up.  If I merely remove all DOS
calls, though, my interrupt routine works perfectly.  (I know it's
getting called because after it installs itself, it runs COMMAND.COM
for me...  when COMMAND.COM returns it deinstalls itself and tells
me how many times it was called.)

A possible related question:  is there some magic rule that says
programs such as this, and terminate-and-stay-resident programs,
must be .COM files?  Mine's an .EXE file (written in CI-C86).

There must be something obscure I'm missing.  I have it 99% right,
because as long as I refrain from calling DOS everything's hunky dory.
What are the magic incantations I need?
   --------