> I've a DS5000/133 at home that had a dead Fujitsu 1GB hard drive in it. 
> I searched through my spare disks and replaced the dead one with a IBM 
> DSAS-3540 (520MB). Now this IBM HD is not seen at all by the PROM...
>     ...
> The only difference in setup (or 
> behaviour) between the RZ55 and the DSAS-3540 is that the RZ55 needs to 
> be sent a "start unit" command to spin up the platters. Do I need to set 
> the IBM to not spin-up on power-on ?

Probably, no.  My bootable NEC is configured as to start spinup on poweron,
and Personal DECstation is running happily with it.

> rz2 at asc0 drive 2 slave 0 nEC D3845 rev 0314
> rz2: 1032MB, 2097 cyl, 16 head, 63 sec, 512 bytes/sect x 2113776 sectors
> boot device: rz2

I have once tried as many modern SCSI disks (and CDROMs, tapes) as
possible hooked with the DECstation for SCSI device driver test,
and found few trouble with PROMs. 

> Or are there some "dirty hacks" in 
> the PROM that allow only certain types of HDs to be booted from ? The 
> (now dead) Fujitsu identified itself as a "Fujitsu M2946", IIRC. So I 
> assume that PROM is not entirely "blind folded" wrt to manufacturers 
> other that DEC, right ?

Tohru Nishimura
Nara Institute of Science and Technology