Subject:	Re: demacs suspend/restart
To:	cremona AT vortex1 DOT ex DOT ac DOT uk (John Cremona)
Date:	Fri, 25 Sep 92 14:02:42 EDT
From:	Stephen Turnbull <turnbull AT ecolan DOT sbs DOT ohio-state DOT edu>
Cc:	djgpp AT sun DOT soe DOT clarkson DOT edu (DJ's GPP mailing list)

> From: John Cremona (Maths) <cremona AT vortex1 DOT exeter DOT ac DOT uk>
> Date: Thu, 24 Sep 92 09:38:22 BST
> Subject: debug32 and demacs
> 
> ....
> 2. Yesterday someone posted hints concerning DEMACS (sorry I didn't
> keep it so don't know who).  I too have had the problem that after
> suspending DEMACS with C-z and restarting with "exit", I SOMETIMES get
> the error that command.com is not found.  Note the sometimes.  The
> cure which always works for me is to resuspend and re-restart as I
> have never got the error the second time.  I DO have the SHELL
> variable set correctly, and I do have the /p set in my config.sys (as
> suggested by yesterday's posting).  Anyone know why and/or how to
> avoid this?
The COMMAND.COM not found error is probably a problem with DEmacs's
shell routines.  I have not had time to try to track it down, but for
anyone who is interested, it is important to notice that the shell
that is not found is the one set by the shell when it starts in
COMSPEC.  My AUTOEXEC.BAT does not SET COMSPEC, it SETs SHELL=
C:/4DOS/4DOS.COM (note: forward slashes;  note: I have tried putting
4DOS in C:\, and also using C:\COMMAND.COM with identical results,
it's not 4DOS for this problem), but when I restart I sometimes get
the error "C:\4DOS\4DOS.COM not found" (note: backward slashes), which
is what 4DOS SETs COMSPEC to.  If I SET COMSPEC=, I then get a system
hang when I try to restart.
    Second point:  as Uwe has pointed out, you will get the problem
after running a real mode program.  If you just use internal commands
*or* DOS-extended programs, you don't get the error.
    Finally, Higashida-san has told me about 6 months ago that the
DEmacs shelling commands are a real kludge, that he debugged them for
personal use on the sushi-flavored NEC PC98 which is not BIOS
compatible, and he's sorry but he won't have time to fix them for
vanilla DOS machines until at least the next release since he's busy
porting MULE (MUlti-Lingual Emacs) for the next release.
    Until somebody goes into the DEmacs DOS shell support code
to verify that this is probably not DEmacs and probably is GO32's
problem, we probably should keep this out of the main DJGPP
discussion.   I'd be happy to summarize.  Unfortunately, a lot of the
participants in this DEmacs discussion seem to have bang-paths in
their return addresses and my mailer doesn't like them; personal
responses will have to wait until I get the sysop to fix the mailer.
-- 
 
Stephen Turnbull
The Ohio State University, Department of Economics
410 Arps Hall, 1945 N. High St., Columbus, OH  43210-1172  USA
Phone: (614) 292-0654  Fax: ...-3906  Email: turnbull DOT 1 AT osu DOT edu

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