Path: utzoo!utgpu!water!watmath!watdragon!rose!rjspitzig
From: rjspitzig@rose.waterloo.edu (Roger Spitzig)
Newsgroups: comp.binaries.ibm.pc.d
Subject: Handling Critical Errors Under DOS
Message-ID: <8110@watdragon.waterloo.edu>
Date: 3 Aug 88 17:26:35 GMT
Sender: daemon@watdragon.waterloo.edu
Reply-To: rjspitzig@rose.waterloo.edu (Roger Spitzig)
Distribution: world
Organization: U. of Waterloo, Ontario
Lines: 12

I am trying to write a TSR or device driver that will trap the DOS critical
error interrupt 24 when the printer is not turned on during a printing
operation.  DOS's normal way to handle this is the "Abort, Retry, Ignore"
message.  This causes screen update problems with many of my applications.
What I want to do is trap the int 24h and if it is an error writing to
a printer (PRN, LPT1,...) I want to pop up a window of my own that will 
save the screen and restore it after the printer has been reset.  
Unfortunately, when you do a TSR, the int 24h vector is reset by DOS.  
Surprisingly, this even happens if you set the int 24h storage vector in
your PSP which is where DOS should be getting the reset value.
Does anyone have any ideas or SOURCE for performing such an operation?
Any help at all would be greatly appreciated.         Roger Spitzig