problems using IDE disk

[Robert Gorichanaz wraith@cinenet.net]

Steve Kotsopoulos (steve@ecf.toronto.EDU) wrote:
: I've tried booting it with my 50Meg IDE disk on and the scsi disk
: turned off, and it's getting a bit farther.


I came across a very kewl situation late last night.  I have a buslogic scsi
card with a seagate 2.1Gb drive, and a VESA IDE card with a couple of old
IDE drives sitting in my closet gathering dust.

My scsi drive is partitioned into 4 chunks - dos/windows, win95, NTserver
and FreeBSD - so there's really nowhere to install Plan9; I need my scsi
disk to be the boot drive otherwise things get really messy.

So, I did this:  I grabbed one of my old Quantum 240's (IDE), installed it
in the BIOS table (AMI Bios 8/24/94), made a 20Mb DOS partition on it and
set it as the active partition.  Then, I installed Plan 9 on this IDE drive
in c:\plan9, rebooted the machine, and installed the other 3 floppies.

I was thinking: This is cool, if I want to run plan9, I just add the IDE 
drive in the BIOS table - otherwise, take it out of the table and the
machine boots off the SCSI disk.

Then, I went 1 farther.  I xcopyied the plan9 directory from C: (the IDE 
drive) to D: (the 1st partition of the scsi disk) and fired up plan9 off
the D: drive - worked like a charm.  It booted, switched over to drive C: 
and asked my if i'd like to start the windowing system - COOL!.

Lastly, I decided "what the hell" and REMOVED the IDE drive's entry from the
BIOS table.  My machine boots up on the scsi disk, I select MS_DOS from my
partition table manager, and booted into DOS.  Then, I ran c:\plan9\b.com
(used to be on D: with the IDE drive installed, but now its C:) and....
....
...
Plan9 from Bell Labs...
<various green text stuff>
<screen clears>

Would you like to start the windowing system? (or something like that)



The moral of the story?  Since Plan9 doesnt rely on your BIOS to establish
what peripherals are attached to your machine, you can pull some rather
strange "stunts".  I can now boot my machine off the scsi disk, and 
access a full plan9 filesystem on the IDE drive.  I even added a little MSDOS
config menu thingy in config.sys to start plan9 right off, without installing
memory manangers and such (plan9 boot doesnt really like QEMM in stealth 
mode!)


Happy Hackin!

-bob