Subject: Re: Archive Viper 150 supported?
To: Joern Clausen <joern@TechFak.Uni-Bielefeld.DE>
From: Jukka Marin <email@example.com>
Date: 03/27/1995 11:16:17
> One thing puzzled me, though: When the tape was rewinding (i.e. my Amiga
> shouln't be involved much in this task), the load-factor of the computer
> went beyond all limits, totally halting the machine. When the tape was
> finished, the load-factor went down again, and I could continue without
> any problems. What kind of effect is this? Does it happen with other
> tapes (e.g. Dat-streamers) as well? Is this something I can avoid by
> fiddling around with some SCSI-bits in the kernel?
This is the very reason why I don't want to run NetBSD on some non-Amiga
This happens because the NetBSD SCSI driver doesn't know how to disconnect.
The tape drive holds the SCSI bus as long as _any_ operation (like rewind)
is in progress. So, NetBSD can not access any disk connected to the same
SCSI bus until the tape drive lets go of the SCSI bus. Thus, no process
can access the disk(s), no swapping can be done etc. Thus, all processes
that want to run, pile up and the load avg rises (load is measured as
number of processes ready to run).
The only way to get rid of this problem is to write a real, fully working
SCSI driver for NetBSD. ;-) :-(