Are old SCSI tape drives not all created equal?

js at js at
Sun Aug 21 12:12:08 CDT 2016

On 8/19/2016 1:08 PM, Chuck Guzis wrote:
> On 08/19/2016 09:24 AM, js at wrote:
>> Where might I find information on how to form SCSI command data
>> blocks so as to try the above commands?   I sent just an "01" to the
>> TEAC MT-2ST, and it did rewind..
> John, what's your working OS platform?  For fooling with SCSI, the ASPI
> interface of MS-DOS is pretty straightforward--and easy to use.

Chuck, for the purposes of testing the Teac drive, I'm using MSDOS on a 486 PC platform with an Adaptec SCSI interface.

> ..and if you goof up, just hit the RESET button and you're back in
> business in a few seconds.
> A CDB's a CDB, so whatever you learn on DOS can easily be transfered to
> other OS interfaces (SPTI, SG, CAM, etc.).
> As far as tape-drive specific commands, there's always an ANSI T10
> document, but that's like trying to learn about parking regulations from
> a university law library--it's probably all there, but you'll have to
> plow your way through a lot of stuff.  FWIW, T10 doesn't refer to the
> things as "tape drives", but "sequential access devices".  Here's a T10
> draft:
> By far and away, the best place to learn practical SCSI interfacing is
> from vendor's manuals themselves.  One I found particularly useful was
> the HP 35470 DDS drive OEM product manual.  Very clear writing style.
> Bitsavers is full of product manuals detailing exactly what and how a
> product supports.

Thanks very much for providing these resource links.

So to recap what it is I *was* trying to do, and am *now* trying to do,
for any readers that are still curious about this:

I was going through various tape drives to see which would be compat with
an Emulux UC07 SCSI interface on a PDP-11/34 and also a Microvax III with
a CMD SCSI interface.

A good -- but not guaranteed -- predictor of which drives would work, is
to first see how well the tape drive will talk to Bart Lagerweij's
SCSI Tool Utility (an MSDOS program) with the drive connected to a PC.

I ran into problems with two drives: an OnStream ADR SC-30 and a Teac
MT-2ST 60MB drive.   I was most hoping the Teac would work as it's a
pretty cool little device, and is closest in vintage to the 11/34
of all my tape drives except for a DEC TS05 and TSZ07.

Unfortunately, I could only get the OnStream the work connected to a
Windows machine -- with the right driver.  Only with the right driver,
will it work with NT Backup or other software.

The Teac isn't working anywhere yet, although the drive appears to
be functional and is responding to a few primitives.

Neither of these two drives is going to work with the 11/34, so that
matter is closed.

The final matter is that I'd still like to get the Teac to function
with some software, just to watch it operate (you have to really like
mechanical things to understand this strange fascination).  Having put
some time and $ into the Teac, it'd be nice to get some reward, even
if only then it gets placed on the shelf afterwards.

- John

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