SS20 multiple boot

["Hal Snyder" <drxyzzy@mediaone.net>]

I'm not up to speed on how the Sun boot prom and OpenBSD's
boot code interact. Is it possible to boot multiple OS's from a
single hard drive?

One reason for asking is that I installed OpenBSD last Thursday
from a mirror site's snapshot onto an SS20 and it failed to boot.
OS seemed to load ok, but on boot from the hard drive it
repeatably went into a Watchdog Reset just after probing sd0.

Friday I installed OpenBSD 2.5, leaving over a GB of space free
on the drive. 2.5 booted ok. If possible, I'd like to try another
snapshot without wiping out 2.5. There is only one hard drive on
the workstation. The initial snapshot download was unusually
slow, so I suspect a corrupt install but would like to make sure
while I have access to this system.