Path: utzoo!utgpu!jarvis.csri.toronto.edu!mailrus!iuvax!rutgers!cmcl2!adm!xadmx!rbw@williams.edu
From: rbw@williams.edu
Newsgroups: comp.lang.pascal
Subject: Re:  Int 1CH
Message-ID: <18269@adm.BRL.MIL>
Date: 1 Feb 89 15:17:55 GMT
Sender: news@adm.BRL.MIL
Lines: 20


> I'm using INT 1CH to install a clock on my screen. Problem is that
> it works when it wants to. 

The first questions I would ask are:
1)	Is your handler using any of the TP I/O calls (read, write, etc)?
	These are not re-entrant, and you may be screwing things up if 
	you call them from an interrupt.

2)	Is your handler taking too long?  I had that problem once.  My
	handler was updating a number of things on certain occasions,
	and it would get caught in the next tick, and my global structures
	would go to chaos or worse.

3)	Are you calling a DOS function?  I can send you some pointers on
	using DOS functions from within interrupts, if you want.


-Richard Ward
rbw@cs.williams.edu		Williams College, Williamstown, MA