>>> You REALLY don't want to be running a tape drive and a disk drive
>>> on the same channel.  If your card has another channel, use it.  If
>>> not, invest in another card.
>> I can't see any reason for this unless the tape drive doesn't
>> support disconnect/reconnect, which anything even vaguely modern
>> should.  [...]  Andy, am I missing something?
> That sounds a little bit like a challenge or something, but I'll
> deflect that.

:-)  Perhaps a bit.  In a case like that, it's entirely possible I am
missing something - but I also might not be, and I regularly see
baseless advice passed around as gospel.

> It's generally not a good idea to use devices of widely varying speed
> on the same bus, especially if those devices are expected to talk
> directly to each other.

Well, in this case, NetBSD doesn't support any effective topology but
the star, with the host at the centre of the star, as far as I can
tell, so every transfer has the host on one end of it.  Which means
that talking directly to another (non-host) device is a non-issue.

If by "widely varying speed" you mean media speed, then I strongly
doubt that there is any real reason behind it.  If you mean bus speed,
then there may be some sense behind it, but it is probably inapplicable
here: a tape drive can be expected to eat the whole transfer fast then
sit there doing nothing on the bus for a comparatively long time while
it performs the write (mutatis mutandis for read).  This is whence the
remark about disconnect/reconnect, because that long delay will be a
performance killer unless the drive disconnects during it to let
something else use the bus.

Even if you mean bus speed, I can't see any reason for it - but I know
I'm no SCSI guru, which is why I asked if I were missing something.

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