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From: mjbo@orstcs.UUCP (mjbo)
Newsgroups: comp.sys.ibm.pc
Subject: Dos Calls and Interrupts
Message-ID: <216700005@orstcs.UUCP>
Date: Tue, 6-Jan-87 18:43:00 EST
Article-I.D.: orstcs.216700005
Posted: Tue Jan  6 18:43:00 1987
Date-Received: Thu, 8-Jan-87 21:58:49 EST
Organization: Oregon State University - Corvallis, OR
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Nf-ID: #N:orstcs:216700005:000:994
Nf-From: orstcs!mjbo    Jan  6 15:43:00 1987

Subject:  DOS calls from interrupts

---------------------------------------

I have read in several places, including the most recent BIX
section of Byte,  that it is not legal to call on DOS
services from an interrupt-service routine.
I would like to write a TSR program to hide in the
background and receive data from a serial port using
an interrupt routine to store the data in a buffer.
When the buffer fills, I would like to store the
data in a Hard-disk file dedicated to that purpose.
(sort of a print spooler in reverse).  Can this be done
safely?   If so, what restrictions are there on the
DOS file-handling calls?   Can a foreground program
read from the input spooler file  without messing 
it up for the interrrupt service routine>

Any hints, answers or references to books or
magazine articles would be appreciated.

Mark J. Borgerson
Dept. of Computer Science.
Oregon State University
(mjbo@orstcs.csnet)  

Just Get my name right--so you don't confuse me with my employer.