[vcf-midatlantic] WTD: PDP-11 tape drive?

Dave McGuire mcguire at neurotica.com
Thu Dec 27 01:51:27 EST 2018

On 12/26/18 9:04 PM, W2HX via vcf-midatlantic wrote:
> I am building my first PDP-11. It is a 11/23+ It is a nice set up with 4 RL02's lots of boards, two half-height racks, spares, you name it.

  Very nice!  Congrats!

> I would really like to get a real-to-real 9-track tape drive, the manual loading kind. I see many autoloading types but they just don't have the panache of what I used to use in the 80's and 90's at my places of work.
> I have been watching on ebay for a while and those few that come up seem expensive. I did locate these (not cheap but cheaper than others).
> https://www.ebay.com/itm/192745726868
> and
> https://www.ebay.com/itm/264099860161
> The first one says "wiltec" but I am guessing that wiltec was just the reseller. It looks very similar (if not identical) to the second one which is listed as a fujitsu M2444AC.

  They are Fujitsu M2444ACs.  These are some of the finest 9-track tape
drives ever built.

> For some reason the "wiltec" one is cheaper. It seems to have some  nice connectors on the back.  The fujitsu is more expensive, has rack mounting hardware (a plus) but no back connectors. It isn't obvious how to connect this to something. Also shipping for some reason, is $100 more.

  The connectors on the other one are a DB25 and a DC37.  These are made
for connection to a Sun VME tape controller like the Xylogics 472 in a
Sun 9U VME carrier.  It would probably be quite a pain to use those
cables with whatever controller you have for Qbus.  In short, the one
with the D-shell connectors on the back is an aftermarket add-on, while
the one that appears to be missing its back cover is more "standard".

  (I think Wiltec sold rebadged Sun systems into ATE or
telephony-related systems.)

  These drives implement the Pertec 2-connector "formatted" interface,
which is carried on two 50-conductor ribbon cables.  That's what any
controller you'd get for Qbus will have.

  A bigger problem will be the power cable.  They use uncommon
connectors (I've forgotten who made them) and are not easy to find.  Of
course you can just replace the connector, but that's a bit of a hassle.
 I see one of the drives you mentioned above has the power cable.

  I see the other one comes with its rack rails.  That's pretty
important, as these are very heavy drives.

> I found a manual to this on bitsavers (thank you to whomever did this). It says it the fujitsu has 3 modes of operation.
> Can they be made to interface with a PDP-11 Qbus system? Anyone have any opinions on these?

  Yes, I recommend an Emulex QT13, that's about the most flexible tape
controller for Qbus.  I've not used one with an M2444AC, but I see no
reason why it shouldn't work.

  Good luck.


Dave McGuire, AK4HZ
New Kensington, PA

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