Add-on second system disk for Personal Iris...problems

[William S. Sinclair]

another front-loading disk, which is on SCSI unit #3. We want to re-install
software on unit #3. As far as I can tell, unit #3 is properly partioned
into partitions 0,1, and 6, like a regular system drive should be. However,
the method suggested by SGI for installing the software does NOT work.
They suggested changing the ROOT and BOOTFILE environment parameters as 
follows:

setenv root /dev/dsk/dks0d3s0
setenv bootfile dksc(0,3,8)sash
According to them, I don't have to do anything to "path".

Then I'm supposed to do an INIT, and go back to the console mode.
When I get the >>, I'm supposed to go to use the INST tool on the
boot tape. When I try to do that, I get a message (after the INST is
copied in) to the effect that the file system on disk #1 (not #3)
has been corrupted, in other words, it tries to do an FSCK on unit
#1, and somehow thinks something is wrong with the entire file
system. The person at SGI made some remark like "Maybe you have a 
bad tape", which sounds like a wild guess. Unfortunately, we can't
easily switch out unit #1 since it's inside the cabinet. For some
reason the system keeps going back to unit #1 even after we change the
environmetal parameters. I have heard some rumor about "a cable that needs
to be changed" if we need to boot from some other disk drive, but so far
it's just a rumor.

Incidentally, I have several tapes with INST on them, and they all do the
exact same thing.

Has anyone tried to do this same thing? If so, I would like to know
how (or if) you got the system disk going. The front loader we have on
unit #3 is a 760 MB (unf) unit from SGI, with CDC as the OEM.
and then doing the regular installation from the boot tape.