Message-Id: <s479d648.027@calderauk.com>
Date: Mon, 24 Nov 1997 19:32:05 +0000
From: Matthias Paul <MPaul AT calderauk DOT com>
To: opendos AT delorie DOT com, paul-ma AT reze-1 DOT rz DOT rwth-aachen DOT de
Subject: Re: questions about loader. 2/2
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<Ok, here s part 2 of the reply:

You just have seen how to decide between multiple AUTOEXEC.BAT s, 
and you might now ask, how to decide between multiple CONFIG.SYS 
files, since there is no SHELL= directive for CONFIG.SYS...

Actually, OpenDOS provides two methods to do so:

- The first alternative is very easy, but restricted to a few parallel 
   configurations:

   OpenDOS, Novell DOS, and DR DOS 6.0 will always search for
   a file named DCONFIG.SYS before looking for CONFIG.SYS. So, you can
   put your OpenDOS configuration in DCONFIG.SYS and your MS-DOS
   configuration in CONFIG.SYS. Note, that the DCONFIG.SYS file
   might also be used for SuperStor or STACKER, so you might not
   be able to use it in this scenario.
   However, my IBMBIO ALPHA3+ and also the future OpenDOS 7.02B2
   will enhance this method by first looking for ODCONFIG.SYS before
   looking for DCONFIG.SYS and CONFIG.SYS. 

  This way you can maintain up to three different configurations. Using
   CHAIN, you can also spawn to the other files if you want to... Please
   recall the recent enhancements with CHAIN introduced with my 
   IBMBIOA3.ZIP. They will also be part of COD 7.02B2.

- The second and more advanced method is to apply different file
   extensions to the CONFIG.xxx file. This can be done automatically
   by SYS /DR:ext, which also changed the extension of the IBMDOS.xxx
   file enabling multiple parallel installations of the same OS to be loaded
   from LOADER s menu, e.g. BOOT.LST:

    IBMBIO.701 S Caldera OpenDOS 7.01
    IBMBIO.702 S Caldera OpenDOS 7.02

   IBMBIO.701 will look for IBMDOS.701 and CONFIG.701, IBMBIO.702
   will look for IBMDOS.702 and CONFIG.702.

   If you don t want to write new boot sectors to the disk, or don t want to use
   different  IBMDOS.COM files for different IBMBIO.xxx files, you can emulate
   SYS /DR:ext using DEBUG manually (instructions can be found in my 
   IBMBIOA3.ZIP archive).
   
Of course, for maximum flexibility both methods can be combined.
Hopefully, this should solve all possible configuration problems 
concerning LOADER.

Matthias



------------------------------------------------------------
Matthias Paul
eMail: <Matthias DOT Paul AT post DOT rwth-aachen DOT de>
Web: http://www.rhrz.uni-bonn.de/~uzs180/mpdokeng.html