>> and then i type /sbin/reboot at the prompt,
>> and this time it works.  it seems as if the rz driver is not giving
>> the disk long enough to spin up?  it only happens when the drive is
>> not spun up before the boot begins.
>
> i've seen some machines formerly running ultrix that had,  um,
>   boot -z 10 3/rzN
>
> as the boot string. The -z 10 causes a wait of 10 seconds for the
> drive to spin up.  -z 15 would wait 15 seconds, etc.

Unless I misunderstood, PROM '-z 10' option cares only a booting disk to
load OS image, not other disk drives happen hooked with DECstation. 

Tohru Nishimura
Information Technology Centre
Nara Institute of Science and Technology