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From: ayac071@ut-ngp.UUCP (William T. Douglass)
Newsgroups: comp.sys.ibm.pc
Subject: Re: DOS Critical-error handler
Message-ID: <5795@ut-ngp.UUCP>
Date: Mon, 3-Aug-87 21:35:08 EDT
Article-I.D.: ut-ngp.5795
Posted: Mon Aug  3 21:35:08 1987
Date-Received: Tue, 4-Aug-87 06:35:45 EDT
References: <1871@isis.UUCP> <1610024@hpcvlo.HP.COM>
Reply-To: ayac071@ngp.UUCP (Bill Douglass)
Distribution: na
Organization: UTexas Computation Center, Austin, Texas
Lines: 20
Summary: Has this happened before?

In article <1610024@hpcvlo.HP.COM> everett@hpcvlo.HP.COM (Everett Kaser) writes:
>Something you should be aware of is that if you bail out of the critical
>error interrupt this way, (i.e. you're not returning back through DOS) you're
>leaving DOS in an unstable state.  When this happens, the next call to DOS
>must be a call below (I think) about 0ch. (i.e. one of the simple console I/O
>routines, such as check for key.)  If not, if you try doing disk I/O or
>something immediately after this bail-out, DOS will be confused as to what
>state it's in, and you may get very unwanted behaviour.

Just out of curiosity, has anyone verified this?  I've read the warning the
the tech manual too, but I have written a critical error handler similar to
the one refered to above (returning without passing control back to DOS) and
implemented it on a menu-system written in Turbo Pascal.  After about a year
now, I've never hung or locked up (running on IBM AT's & XT'x, DOS 3.00 +).

Would anybody mail me if they have had such a problem as mentioned above. 
Thanks in advance.

Bill Douglass
ayac071@ngp.UUCP