3130 disk problems

[Jim Diamond]

Hello:

I have a 3130 with the SGI-supplied (Hitachi?) DK512-17 disk drive as
well as a CDC 380 Mbyte drive I installed myself.

The system crashed the other day and attempts to boot (off disk)
fail with
	SGI Extent Filesystem
	hd.0:defaultboot: No such file or directory
and attempts to look at the disk with the prom "ls" command return
	SGI Extent Filesystem
	can only ls disk or tape devices
	bad mode for hd.0:/ (0x0)

I assumed that the disk was dead, but I tried running sifex (which
I have installed on disk 1) by running
	b si.1:stand/sifex
and was surprised to find that, as far as I can see by read tests,
updating the label, and copying partition "a" from disk 1 to disk 0,
sifex has no problems with the disk.

Anyone have any ideas as to what might be wrong, or what I might do to
avoid throwing away the Hitachi disk?  Thanks.

			Jim Diamond
			zsd at pig.drea.dnd.ca