29 Sep
2014
29 Sep
'14
8:42 a.m.
On Sun, Sep 28, 2014 at 2:40 PM, Pontus <pontus at update.uu.se> wrote:
In another box was a CMD CDU-720/T. A Unibus scsi tape controller, same
question here, can you coax it to talk to disks?
The CMD CDU-720/TM firmware version B2A is available on the archive of
the CMD website.
https://web.archive.org/web/19961226090740/http://www.cmd.com/ftproot/pub/d…
The manual lists three different versions of the CDU-720 CSR decode PAL:
CDU-720/TM - P72008A in U102
CDU-720/M - P72009A in U102
CDU-720/T - P72010A in U102
If it works the same as the CMD CQD-220 then simply replacing the
CDU-720/T firmware with the CDU-720/TM firmware is not sufficient by
itself, you also need to replace the CSR decode PAL.
On the CMD CQD-220 the CSR decode PAL has separate decode output pins
for the MSCP and TMSCP addresses. On the /TM version both outputs
could be driven true for the appropriate addresses. On the /T and /M
versions one of the outputs would always be driven false. If the CMD
CDU-720 uses the same scheme for the CSR decode PAL it shouldn't be
too difficult to reverse engineer the decode PAL for a CMD CDU-720/TM.
I have a CMD CDU-720/M that I could look at to give this a try
sometime.
-Glen