From: dallasii AT kincyb DOT com
Date: Wed, 10 Dec 1997 07:08:32 -0700 
Message-ID: <TCPSMTP.17.12.10.7.8.32.2375661496.4855232@kincyb.com>
Subject: Loader Madness
To: opendos AT delorie DOT com
Precedence: bulk


I'm crossposting this to the Orange County Linux User's Group (OCLUG),
the Open DOS User's list and Glenn Currie, long time friend and
UNIX/NT consultant in Austin, TX.  I haven't decided whether to 
send it to the DOSEmu mailing list, Linux Gazette or Paul Wirtz, 
my OS/2 mentor - let me know what ya'll think about sending this to
them? ;-)

1) Using SID (yes SID, not DEBUG :-) ), I patched the
   IO.SYS (MS-DOS 5.0) and IBMBIO.COM (DR DOS 5.0) so that
   they looked for (D)CONFIG.XXX, (*.XXX=M50 for MS, D*.XXX=500 for DR)
   instead of the usual CONFIG.SYS.
   This avoids conflicts between between CONFIG.SYS for MS-DOS and
   OS/2 Warp, and DCONFIG conflicts for DR and Calder DOS.  
   IO.SYS had 4 places the filename had to be
   changed, IBMBIO.COM only one.  The boot sectors and files
   could probably also be patched to change the extension for
   the boot files (IO.SYS, MSDOS.SYS, IBMBIO.COM, IBMBIO.COM).

2) Re-"SYS"'ed the disk for OpenDOS 7.01, with the undocumented
   /DR switch explained by Matthias Paul (OpenDOS User's list, Ger.):

   SYS a:\ c: /DR:701

   so that now it's boot files are IBM*.701, and DCONFIG.701.

These two steps remove the need for anything but overwriting
the partition boot sector and doing a warm reset to switch
between these OS's.

3) Now, do another OpenDOS "SYS" with /DR:U00, with 
   CONFIG.U00 having:

   HIINSTALL=C:\BIN\AVERKEY.EXE         (TO INSTALL VGA TO NTSC(VIDEO)
                                         TSR (I essentially use a TV for
                                         a monitor using the AVERKEY 
                                         scan converter))
                      
AND
   SHELL=C:\LINUX\LOADLIN.EXE C:\LINUX\VMLINUZ

This setup, based on procedures outlined in the AUG. '97 
LINUX Gazette, allows the same BOOTSECT.COM & warmboot I use
to switch between DOS's to now be used to switch to LINUX.
Going the otherway, (this hasn't been done yet), 'dd' the partition 
boot sectors saved in a directory, with 'shutdown -r now' will enable
booting to any of the DOS's from LINUX, with basicly the same steps.

4) Now, install Loader, from the OpenDOS 7.02 Beta, with the following
   BOOT.LST file:

ibmbio.com      D       DR DOS 5.0
os2ldr          O       [10] OS/2 Warp 3.0
ibmbio.701      S       Caldera OpenDOS 7.01
ibmbio.u00      D       Linux
msdos50.exe     B       MS DOS 5.0

Now, F1 brings up IBM Boot Manager, F2 -> DR DOS, F3 -> OS/2,
F4 -> COD 7.01, F5 -> Linux.
MS-DOS 5.0 doesn't work this way yet because I haven't created
the booting stub described by Matthias Paul in the recent flurry
of Multi-Boot discussion on the OpenDOS mailing list.

Notes: A) Loader *must not be installed* for SYS'ing the C: partition
          with the OpenDOS SYS and it's /DR: switch.  If it is,
          a new partition boot sector is not created, even though
          the IBM*.<ext> files will be.

       B) When Shell=<something other than DOS>, 
          (such as an application like LOADLIN) apparently
          the Loader menu.lst file must be 'D', not 'S' for OpenDOS.

       C) LOADER causes the bypass of the partition boot sector       
          unless F1, IBM Boot Manager is chosen from the
          LOADER menu, then the C: partition is chosen from the
          Boot Manager menu.  Untill the booting stub is created,
          this is the only way to boot MS-DOS.

       D) DOS version or LINUX can be targeted for the process
          described in C) above, by COPYing the appropriate
          boot sector file over C:\OS2\SYSTEM\BOOT.DOS,
          then executing the OS/2 BOOT /DOS command /
          clicking on the Dual Boot icon in the Command Prompt folder.

        E) DR/Novell/Caldera Open DOS's all automaticly set two variables
           during bootup, OS and VER, that can be used as an alternative
           to branching AUTOEXEC.BAT to the 'real' autoexec.bat file
           based on the COMSPEC setting left over from the execution
           of CONFIG/DCONFIG.  An example 'universal', multi-OS
           AUTOEXEC.BAT:

IF (%OS%)==(DRDOS) IF (%VER%)==(5.0) C:\DRDOS50\AUTOEXEC.BAT
IF (%OS%)==(OPENDOS) IF (%VER%)==(7) C:\OPENDOS7\AUTOEXEC.BAT
REM
REM  above for DR/Novell/Caldera DOS's
REM
IF (%COMSPEC%)==(C:\MSDOS50) C:\MSDOS50\AUTOEXEC.BAT
IF (%COMSPEC%)==(C:\MSDOS50\COMMAND.COM) C:\MSDOS50\AUTOEXEC.BAT
REM
REM               above for MS-DOS 
REM                  does not set OS & VER during boot, so must
REM                  use COMSPEC, set by SHELL= in CONFIG file
REM
IF (%COMSPEC%)==(C:\OS2\MDOS) C:\OS2\MDOS\AUTOEXEC.BAT
IF (%COMSPEC%)==(C:\OS2\MDOS\COMMAND.COM) C:\OS2\MDOS\AUTOEXEC.BAT
REM
REM                 The above for default DOS emulation 
REM                   (VDM - Virtual DOS Machine) under OS/2
RE<
IF (%OS%)==()      IF (%VER%)==()    C:\MSDOS50\AUTOEXEC.BAT
REM
REM         the above if anything is seriously wrong. :-)
REM

I just need to write the bash scripts under LINUX,
and *.CMD files under OS/2 to get transitions to work smoothly
like the DOS's when Boot Manager is selected from the LOADER
menu.  Nothing more is needed, however, to boot any of these systems
from the LOADER menu, all are treated equal.  In this case,
the partition boot sector is bypassed, and the selected system is
booted.  A simple shutdown from any of them, reboots LOADER installed
on the master boot sector, and it's menu comes up.

One intresting experiment, still underway, is booting Specific DOS
versions under OS/2 (VMB - Virtual Machine Boot) from Drive C:, when
booting OS/2 with DOS still installed on the partition boot sector.
This brings up the LOADER menu, and you can select which DOS version
to run then, instead of needing to have a seperate disk image
for each version of DOS you want to run as an application under OS/2 Warp.
The same should be possible under DOSEmu in LINUX.  
This hasn't been fully explored yet, but the possiblities are
making my head spin. :-)

I still need to write a machine code program to install along
with LOADER, to activate my AVERKEY vga/video converter during
the LOADER menu - for right now I just wait for the beep during
the machine's boot, and select the OS from memory.

Also, I haven't put LINUX on the Boot Manager list, but there
are some possibilities brewing there.

I know there are at least two German speakers on the OCLUG
list, any volounteers there to help get Matthias Paul's DOS documents
translated into English?

The following people/organizations helped make this possible.
In memory of Frank Zappa, "Please do not hold it against them":
Matthias Paul (Germany, OpenDOS mailing List), 
Caldera, Linux Gazette.


Regards,
Dallas E. Legan II
(562) 862 - 4854 ext. '*'
legan AT acm DOT org
legan AT forth DOT org
aw585 AT lafn DOT org
dallasii AT kincyb DOT com

"But I found that the rulers were ordinary men, too, and frequently
as bewildered as I was."

                from "Solution Unsatisfactory"
                   by Robert A. Heinlein

I speak only for myself, and assume full responsibility for my statements.