From: "Weiqi Gao" <weiqigao AT crl DOT com>
Newsgroups: comp.os.msdos.djgpp
Subject: Re: Install bash as DOS 6.22 shell
Date: 1 Dec 1996 15:09:50 GMT
Organization: CRL Dialup Internet Access
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Message-ID: <01bbdf99$7ce9ad60$010200c0@weiqigao>
References: <Pine DOT ULT DOT 3 DOT 95 DOT 961125182733 DOT 7399C-100000 AT ananke DOT amu DOT edu DOT pl> <329C7249 DOT 6F04 AT cornell DOT edu>
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To: djgpp AT delorie DOT com
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A. Sinan Unur <asu1 AT cornell DOT edu> wrote in article
<329C7249 DOT 6F04 AT cornell DOT edu>...
> Mark Habersack wrote:
> 
> > DOS 6.2x has the INSTALLHIGH command, only it's undocummented.
>  
> install or installhigh do not help with installing bash as primary dos
> shell because (as you can clearly see if you step through config.sys),
> install and installhigh commands are executed after shell=whatever.
> 
But the SHELL=D:\USR\BIN\BASH.EXE line is executed after CONFIG.SYS is done
and right before AUTOEXEC.BAT is started.  It is at that point that
BASH.EXE cannot be started, and COMMAND.COM is called upon to provide the
shell service.  As was pointed out in previous posts in the thread, this is
because bash.exe doesn't comply with the 'DOS Shell Specification'
(whatever that is).
> 
> > >1.  bash.exe still has problem starting up as a DOS shell.  Whereas my
> > >error yesterday was "No DPMI" and then "Your command processor is no 
> > >good",
> > >today, the message is ": cannot open." followed by "Your command 
> > >processor is no good."
> 
> > That's probably because bash does not comply with the shell 
> > specifications for DOS. But there's nothing wrong in loading it as a 
> > normal app. It will remove the transient part of command.com from the  
> > memory anyway. And since bash won't ever return - you'll have no memory

> > loss.
> 
> what do you mean by your last comment???

COMMAND.COM is loaded into two different places.  The resident part goes to
the bottom of DOS memory and will be there for ever.  The transient part
goes to the top of DOS memory.  The transient part may be overwritten by a
DOS program is the memory requirement of the DOS program ever become that
great (as to go all the way from just above the resident part of
COMMAND.COM to the top of DOS memory).  DOS knows it when it happens, and
reload that portion of COMMAND.COM from the disk when needed.

This phemomenon is most visible on a floppy system, where every time DOS
needs to do this, it instruct you to "Please insert the systems diskette in
drive A:".

-- 
Weiqi Gao
weiqigao AT crl DOT com