Dual boot capability

[Michael Sweeney]

I have a need to be able to boot an Indigo2 system under either 5.3 or 6.2.
I have two drives (one with either operating system), and I can mount the
5.3 drive under 6.2, but the need is to be able to boot under the OS of
choice without having to physically swap drives. So far, this capability is
completely eluding me. Any pointers would be greatly appreciated. Thanks.

Mike Sweeney
swe...@dvart.com

[Mark Mitchell]

Mike,
I've got an IRIX 5.3 disk on ID 1, and a 6.2 disk on ID 2. To boot
IRIX 5, I run the following script:

nvram -v SystemPartition "dksc(0,1,8)"
nvram -v OSLoadPartition "dksc(0,1,0)"
/etc/reboot

or to boot IRIX 6:

nvram -v SystemPartition "dksc(0,2,8)"
nvram -v OSLoadPartition "dksc(0,2,0)"
/etc/reboot

I hope this helps.

By the way - be careful if you're changing the scsi IDs of these disks. E.g. if
you've currently got both disks on ID 1. The scsi ID (or some reference to it from
/dev/root) is compiled into the kernel: if you change the scsi ID of the disk and
try to boot - it'll fail - or it'll load the kernel off the disk at ID 1.

If you do have this situation, (and you don't want to re-install):
- set your 6.2 disk to scsi ID 1
- boot
- change /dev/root and /dev/rroot so that the minor numbers are correct for the
new scsi ID: it'll be the same as the fs partition containing unix:
e.g. for ID 2, partition 0:
ls -l /dev/rdsk/dks0d2s0
brw------- 2 root sys 128, 32 Oct 8 11:49 dks0d2s0
giving a major number of 128 and a minor number of 32.
Create the new devices with:
mknod /dev/root b 128 32
mknod /dev/rroot c 128 32
- run /etc/autoconfig
- Shutdown, set the scsi ID to the new ID and boot.

This last section should probably have "use at your own risk" and "may be a bad
idea" plastered all over it.

Mark.

--
Mark Mitchell - SG Development manager | ma...@k-par.co.uk
K-PAR Systems Limited, | Phone: (0117) 9421 141
174 Cheltenham Road, Bristol | FAX: (0117) 9420 564
England. BS6 5RE | WWW: http://www.k-par.co.uk/

[Ping Huang]

> I have a need to be able to boot an Indigo2 system under either 5.3 or 6.2.
> I have two drives (one with either operating system), and I can mount the
> 5.3 drive under 6.2, but the need is to be able to boot under the OS of
> choice without having to physically swap drives. So far, this capability is
> completely eluding me. Any pointers would be greatly appreciated. Thanks.

See
-18- How can I boot from a non-default disk?
in the admin FAQ maintained by sgi...@viz.tamu.edu.

http://www-viz.tamu.edu/~sgi-faq/

--
Ping Huang <psh...@sgi.com> | Silicon Graphics, Inc., Mountain View, CA
http://web.mit.edu/pshuang/.plan; PGP: 1906684DD1537EC4 30876EACC18ADFC5
Disclaimer: unless explicitly otherwise stated, my
statements represent my personal viewpoints only.