Help with SCSI tape on PDP-11 with RT-11

From: <(>
Date: Sun Jul 11 08:33:14 1999

> Well, I need some help with a SCSI tape drive!!
>Hardware: CQD 220/TM set both ways for W3-6
> W2 is out, standard CSR
> for tape
> TZK12-AA with jumpers OOOOOCCOOC
>Software: RT-11 V5.6
>BUT, when I try to do a COPY DU0:a.b MU0:a.b
>the system hangs without having written anything to MU0:
>When I try to do a BACKUP DU0:a.b MU0:a.b
>I get 2 error messages saying it couldn't do the BACKUP
>and quits, again without writing anything to MU0:

It would be nice if every tape drive reacted the same way to SCSI
commands, but this simply isn't the case. If you can try a different
SCSI controller (or even a different firmware revision) or a different
make of tape drive you'll probably have better luck.

The fact that you can do some very simple operations, but not some
more complicated operations, points to the problem being with certain
SCSI "position tape" commands. This isn't too surprising if (as
I'm assuming) this is a QIC cartridge drive - these often balk at
filemark and record skips, *especially* in reverse (which is something
that RT-11 will try to do for PIP-type operations for sure.)

>Please, any suggestions would be helpful.

I wish I could give you better advice than "it's hit and miss", but
that advice would be "only use devices that the company that made your
SCSI host adapter is willing to support", and this is often excessively
restrictive. I think the CMD's are only qualified against Exabytes
and some 4mm cart drives (at least they were when I bought my new CQD-440
most of a decade ago.)

 Tim Shoppa                        Email:
 Trailing Edge Technology          WWW:
 7328 Bradley Blvd		   Voice: 301-767-5917
 Bethesda, MD, USA 20817           Fax:   301-767-5927
Note that when I substitute a TQ50/TK50, everything
is OK with respect to PIP and BUP.
Sincerely yours,
Jerome Fine
Received on Sun Jul 11 1999 - 08:33:14 BST

This archive was generated by hypermail 2.3.0 : Fri Oct 10 2014 - 23:32:11 BST