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Article View: comp.sys.zenith.z100
Article #116

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#116
From: Drew Derbyshire
Date: Wed, 20 Sep 1989 01:06
48 lines
2821 bytes
You are confusing the SHELL parameter (in CONFIG.SYS) and COMSPEC.  The
actual scenenero that is happening to you is like this:

        You boot off B:  drive (MSDOS.SYS and IO.SYS are read from
        the drive at this time, once and for all.  No need to copy
        them to RAM drive).

        MSDOS.SYS reads CONFIG.SYS and uses SHELL (or the default) to
        load COMMAND.COM from B:.  MSDOS.SYS remembers this value,
        so that you _always_ will re-load the the originally
        loaded shell program.  By the way, the default is
        actually:

                        COMMAND.COM /P          (/P = permanent)

        You set COMSPEC to 'anything'; now, if you invoke Kermit,
        Freemacs, or any other program that supports invoking
        MS-DOS from within the program (or implicitly invokes it
        for functions such as DIRectory), you will get this
        'other' COMMAND.COM (or whatever), invoked via

                'anything' /C command

        HOWEVER, the original COMMAND.COM's location is retained,
        lest the memory be reallocated to a user program (not
        corrupted, this term means a program walks on memory it
        does NOT own), and COMMAND.COM needs to be reloaded.  In your
        case MASM allocates the memory and then returns it, and
        COMMAND.COM is then reloaded from B:

The solution is to use a program that is invoked by the SHELL parameter
in CONFIG.SYS, which copies the COMMAND.COM to your RAM drive and then
invokes it with the /P option.  This leaves the permanent copy of
COMMAND.COM on the RAM drive.  I wrote a version of the program to
correct exactly the problem you describe.  My version was on
clutx.clarkson.edu in pub/shell.asm, the last I knew.  You may need to
tweek it for your version of MS-DOS, see the comments at the top of the
program.  Please let me know if this helps you.
-- 
Drew Derbyshire

Internet:  ahd@clutx.clarkson.edu             Voice:  914-339-7425
   UUCP:   ahd@kendra.wf.ags.com         Snail mail:  578 Broadway, Apt 6
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From: ahd@kendra.wf.ags.com (Drew Derbyshire)
Newsgroups: comp.sys.zenith.z100
Subject: (none)
Message-ID: <2516e281@kendra.wf.ags.com>
Date: 20 Sep 89 01:06:09 GMT
Sender: daemon@ucbvax.BERKELEY.EDU
Reply-To: Drew Derbyshire <ahd@clutx.clarkson.edu>
Organization: AGS Information Services, Wappingers Falls Office
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