dual boot Plan9/Win95

dual boot Plan9/Win95

[Castor]

I installed Microsoft Windows 95 on my laptop  which already
had Plan9 9 happily running.  With a little work, I've gotten
Plan 9 and Win95 to coexist in a dual boot situation, and 
no longer  have to boot into MS-DOS.  Hopefully
these notes will help others that want to do the same.

MS Win95 has three main configuration files in the boot phase.
I found documentation on these in the "Windows 95 Resource Kit"
which was located in the "ADMIN" directory of the distribution
CD-ROM.  These files are:

msdos.sys:
	controls the initial boot menu, dos/win95 dual boot, etc.
	When screwing around with config files, it's good to
	set "BootMenu=1" here to allow safe exit.

config.sys:
	used to load real mode drivers, i.e. dos/windows holdovers
autoexec.bat:
	Used to set environment variables, and has some
	ability to run programs.

In config.sys, it's possible to set up multiple boot configurations,
but the execution rules do not seem to be the same as in MS-DOS.  For
Plan9 I set up a boot configuration which immediately installs B.COM.
Win95 versions of drivers like "setver" and "emm386" and the I/O
Redirector still seem to get loaded.  Luckily they don't seem to
conflict with b.com.

Things seem to work pretty well.  The most noticeable problem
is that rebooting with "^T^Tr" does not work going back into
Win95, probably because the Plug and Play BIOS does not get 
re-executed.

I used the following in my config.sys file:
	[menu]
	menucolor=10
	menuitem=win95
	menuitem=plan9
	[win95]

	rem These two lines processed by io.sys in win95
	DEVICE=C:\WINDOWS\SETVER.EXE
	DEVICE=C:\WINDOWS\HIMEM.SYS/M:2 /testmem:off

	rem handled by io.sys in win95
	DOS=HIGH,UMB
	FILES=40
	LASTDRIVE=Z

	rem leave space for cardsoft
	rem emm386.exe processed by config.sys in w95
	device=C:\WINDOWS\emm386.exe on X=D000-DFFF
	break=on
	
	SHELL=C:\COMMAND.COM C:\ /P /E:1024

	[plan9]
	install=c:\plan9\b.com

My MSDOS.SYS looks like:
	[Paths]
	UninstallDir=C:\
	WinDir=C:\WINDOWS
	WinBootDir=C:\WINDOWS
	HostWinBootDrv=C

	[Options]
	BootGUI=1
	Network=1
	; Setting this to one forces the boot menu
	BootMenu=0
	BootMulti=1

	; following lines are required for other programs.
	; Do not remove them (MSDOS.SYS needs to be >1024 bytes).
[  dos fodder elided ]

--------------------- Castor Fu              +1.512.433.3329 <castor@tkg.com> 
         The Kernel Group, Inc.                           http://www.tkg.com/