[Gloucs] Sun SCSI Disk stuff

[Glyn Davies]

At the last GLUG meeting I promised to post some details on Sun 
workstations and detecting the SCSI ID (I think it was for David & 
Sharon - apologies if I got the wrong couple).

Right.

You had 4GB and 40GB hard disks.

Assuming the 4GB (as supplied) is in the machine.

Power on the machine and use STOP-A to get to the 'ok' prompt.

Type probe-scsi

This command will list the SCSI devices attached to the machine.

You should be able to spot the SCSI ID of the 4GB drive. It will be a 
number between 0 and 7 or 0 and 15. IIRC 7 is the SCSI controller so the 
HD won't be that.

Having now noted the ID (lets say it was 3) you can now set the 40GB 
drive to a different value. Lets say '0' (as it easiest).

On the back of the HD by the big connector will be some jumpers which 
set the SCSI ID. There are others but they need not concern us at the 
mo. The SCSI ID jumpers are usually labelled either 4 2 0, 4 2 1, ID3 
ID2 ID1 or 3 2 1. If the drive is a recent one (less than 5yrs) it may 
have a 4th ID pin labelled 8 (as in 8 4 2 0) or 4 (as in 4 3 2 1). When 
a jumper is shorted (connected together) consider it a binary 1. Open 
circuit (no jumper connector) is a binary 0. So this gives us the 
possible settings

Jumper Pin	SCSI ID
8  4  2  1		
-----------------------
x  x  x  x	0
x  x  x  I	1
x  x  I  x	2
x  x  I  I	3
x  I  x  x	4
x  I  x  I	5
x  I  I  x	6
x  I  I  I	7
I  x  x  x	8
etc up to
I  I  I  I	15

I=connected together
x=open circuit

So, for a SCSI ID of 0 we need not connect ant pins together.

So, with two HDs with different SCSI IDs if you have them connected to 
the SPARC at the smae time a 'probe-scsi' command should show both 
drives listed.

If you can only connect one at a time, set the ID to the same as the 4GB 
  drive. One of the PROM (that's the ok prompt thingy) environement 
variables set the HD disk to be used when boot from disk (e.g. boot 
disk). This setting maps to a SCSI ID which you would have to change if 
you used a differnet ID. To see all the setting type 'printenv' at the 
'ok' prompt.

There's loads more to this so please shout if you want more info or 
would like to move to the next stage (attempting an install).

One final thing, when messing with the HDs, and jumpers et al, power off 
the SPARC.

HTH
-- 
Best Regards
Glyn Davies