Subject: Archive Viper hogging SCSI

From: Andrew Cherry <[email-masked]>

I have an A2000 with a GVP Series II SCSI controller.  I've noticed
that when I use my Archive Viper tape drive, some operations
will hang the whole system until completion (in particular,
"mt rewind" will hang everything up until the tape is finished
rewinding).  Does anyone know of a way to keep this behavior from
happening, or is it possible with this drive/controller combination?
It is quite annoying, and makes the system essentially unusable
during (and especially, immediately after) doing a tape backup.

-Andrew Cherry

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From: [email-masked] (Markus Illenseer) "Archive Viper hogging SCSI" (Sep 2, 5:26pm)

> during (and especially, immediately after) doing a tape backup.

 Normal behaviour. NetBSD-Amiga does currently not support disconnect/reselection
for SCSI. This means yor tape is being rewinded in busy-loop i/o...

-- 
Markus Illenseer

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From: "Richard H. Wood" <[email-masked]>

[email-masked] wrote:
> 
> 
> Unfortunately the current SCSI drivers do not support disconnect
> so when you issue a command like rewind it must first complete
> before the SCSI bus is again free to do other things.
> 
> Chris.
> 

I consider this a bug.  (and shouldn't that actually read "any command" 
- not just "a command like rewind"?)

I've had to newfs a couple of times when the tape drive _never_ came 
back with a reply!  Gives new meaning to "deadly embrace".

System hangs while rewind 250 meg tapes take far too long to be considered 
acceptable in the long term.  So, is this on somebody's list to be fixed?  
Or, can the old scsi driver be dropped back in at this point without too 
much work?  It used to support disconnect _and_ supported the Archive Viper 
drive rather well, too.

Here's an example:  Yesterday I had an old NetBSD tape (from last summer, 
with like 644 and 720 on it - I never got copies of 744) which my NetBSD 
1.0beta refused to read: no errors, no nothing.  Like it just had an EOT 
on it at the front.  System would read another tape just fine (I wanted 
to see if I could combine the contents of the two tapes but the system
wouldn't cooperate.

So, I took the same tape(s) to work - a Sparc2 and a Sun (Archive drive, 
I can see it's name through the slot) Tape drive - and it ready them 
beautifully!  First "rattle out of the box" so to speak. ;-)

So, I'm becoming rather frustrated with the state of the present scsi 
driver.  But my "blame" _may_ be misplaced, but exacerbated by what I 
(perhaps erroneously) also perceive as scsi driver problems with some
disk behaviour am seeing.  Let me explain.

I just added a 1.<something) gig drive about two weeks ago, and on my 
largest partition, (about 1/2 meg) I'm consistently getting corrupt 
directory errors from fstat on that partition.  (It was over 700 meg, 
and I broke it up, to see if smaller partitions would make the problem 
go away...it didn't)

Now my question is, is the scsi driver possibly to blame for this?  I
wanna learn more - that's why I added the big drive, so I could have
room for the sources and all - to study.  But since I'm still somewhat a
novice in speculating the source of problems like these, and I yield
to the wisdom of the guru cadre. ;-)

-dick
-- 
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From: [email-masked]

> This is just wrong, NetBSD/amiga has *never* supported disconnect.  The
> old tape driver may have had a hack to support a rewind command that
> completes immediatly however the next command sent to the tape would
> then hang the scsi bus until the rewind completed.

Eh if you think about it, it would block too in this case even if the
driver supported disconnect/reconnect, right?:-) No, I don't recall whether
there was such a hack in the st-driver, I know the scsi-subsystem didn't
do disc/rec, that's correct.

-Markus
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