From owner-freebsd-questions Sun Aug 25 20:26:31 1996 Return-Path: owner-questions Received: (from root@localhost) by freefall.freebsd.org (8.7.5/8.7.3) id UAA13854 for questions-outgoing; Sun, 25 Aug 1996 20:26:31 -0700 (PDT) Received: from freenet.hamilton.on.ca (main.freenet.hamilton.on.ca [199.212.94.65]) by freefall.freebsd.org (8.7.5/8.7.3) with ESMTP id UAA13848 for ; Sun, 25 Aug 1996 20:26:24 -0700 (PDT) From: hoek@freenet.hamilton.on.ca Received: from james.freenet.hamilton.on.ca (james.freenet.hamilton.on.ca [199.212.94.66]) by freenet.hamilton.on.ca (8.7.5/8.7.3) with ESMTP id XAA21679; Sun, 25 Aug 1996 23:26:21 -0400 (EDT) Received: (from ac199@localhost) by james.freenet.hamilton.on.ca (8.7.5/8.7.3) id XAA29753; Sun, 25 Aug 1996 23:28:04 -0400 (EDT) Date: Sun, 25 Aug 1996 23:28:04 -0400 (EDT) Message-Id: <199608260328.XAA29753@james.freenet.hamilton.on.ca> X-Mailer: slnr v.2.13 as ported to FreeBSD To: KUMAR@BOGPO1.CO.unisys.com cc: "questions@freebsd.org" Subject: Re: Help! Sender: owner-questions@freebsd.org X-Loop: FreeBSD.org Precedence: bulk In Email, "Kumar, Rao CO" wrote: > > Thanks in advance for your time. I saw your mail id on the Internet. So I am > sending you this mail > and would highly appreciate your help. The newsgroup comp.os.msdos.programmer would be a better forum for this question. The mailing-list questions@freebsd.org is intended for answering questions from users of the FreeBSD UNIX-like operating system. MS-DOS has extremely little to do with FreeBSD (fortunately). However, > I have written a TSR (that runs on MS DOS 6.2) that intercepts the interrupt > 1C (timer interrupt). What I am > trying to do in this interrupt handler is some file i/o (using fopen, fread > and fclose of Microsoft C). I'd guess your first problem is that you are using supplied library functions. > At times the system hangs. I thought it was due to some conflict in > simultaneous handling of interrupt 21h by the file i/o calls inside my > routine and the foreground application. So I tried to do a check for the > InDOS > flag before proceeding with my interrupt handling routine, but this flag is > always 1 when my interrupt > routine is invoked (even when there is no front end application). Probably because the InDOS flag is not being set by the front-end application, but by your interrupt handling routine. > 2. Is there any other way to know if MS DOS is executing a 21h interrput ? Insert your own 21h interrupt handler to log whatever goes on? -- -- tIM...HOEk The opinions expressed above are mine, and if my employer shares them, that's his hard luck.