A new haul - questions on TA81 and TA78

From: Eric Smith <eric_at_brouhaha.com>
Date: Sat Feb 5 17:32:31 2005

> Is it possible to change the TA81 into a TU81?
> Would it only require a change of the interface controller card?

I think you have to replace more than one card, but I'm not 100%

> Now the question on the TA78.
> Edward looked into this beast for a short moment, and he noticed that
> some flatcables come from the drive which go to a box. The flatcables
> give the impression that those are a Pertec interface. In that case,
> the box would be a converter between Pertec and Massbus?

No, a TU78 master drive has a TM78 formatter that talks Massbus. The
TA78 has a formatter that talks STI, same as the TA81. If you replace
that formatter with a TM78, it will talk Massbus. (And then I want
the STI formatter.)

DEC made are no Qbus or Unibus controllers that could talk to the
STI tape drives. I'm not aware of any third-party ones either. STI
tape drives were used on HSC controllers (with a suitable channel
card), or the KDM70 XMI-to-SDI/STI controller (T2022 and T2023 module),
or the KDB50 BI-to-SDI/STI contrller (T1002 module).

> Any tips on getting a TA81 connected to a PDP-11/44 (which has some
> RA81/RA60 SDI drives connected to it) are very much appreciated!

Only by replacing the formatter with the TU81 LESI formatter. (And
if you do that, I'd like to have the TA81 formatter.)

> The TA81 has connecting cables that *look like* SDI, but from the
> User's Guide I understand that it is not SDI, but HSC ...?

It's STI. Electrically compatible with SDI, but different protocol.
Unfortunately the UDA50 will only talk to disk drives (SDI) but not
tape drives (STI).

I've been hoping to get some STI tape drives (TA78, TA79, TA81, etc)
for eventual use on a PDP-10 system with an HSC50. I still need to
get the HSC50 as well; I could trade an HSC70 for one.

Best regards,
Received on Sat Feb 05 2005 - 17:32:31 GMT

This archive was generated by hypermail 2.3.0 : Fri Oct 10 2014 - 23:37:36 BST