29 Sep
2014
29 Sep
'14
12:41 p.m.
2014-09-29 10:15 GMT+02:00 Pontus Pihlgren <pontus at update.uu.se>:
I'll put it on the TODO list, any reason you think a new PAL is needed
on this board but not the qbus one?
Some of the QBUS cards already were QDT, those are not requiring a new PAL.
But the QTO need a new PAL, likewise the UTO need a new PAL.
Again, I'll put it on the TODO list. I must one of my UNIBUS machines
runnable first.
Lets work something out further on, I'm rather swamped now.
/P
On Mon, Sep 29, 2014 at 08:28:07AM +0200, Mattis Lind
wrote:
Well. I was unclear. You need the PAL to make it look like a QDT from the
QBUS / UNIBUS. It is only handling the address decoding. I did investigate
the PAL and how it was connected. There were two outputs that ended up in
some other PAL. I think this is "Disk"-select and "Tape"-select wires.
So
the removable PAL is used to on the QTO only enable the "Tape" signal while
on the QDT enable both of them, but for different addresses.
But the controller itself would happily work fine as a QDT while the PAL is
a QTO.
The Viking card has two UART serial ports on the
DB50 connector which is
split out by the cab-kit. It would be very easy to do your own. And
without
the cab kit you cannot talk to the board which is
very useful to do. The
pins used for the serial ports are 20,22, 28,30.
Ah, yes that is simple enough.
As far as I understand these signals normally are
ground signals. I guess
that the RS232 drivers has some kind of protection on the outputs and
could
handle the short circuit to ground which would
happen if you connect the
drive directly.
I think I'll go ahead and try to see if its working, perhaps make a cut
in the ribbon cable and leave them floating just to be sure?
Here is the manual:
https://dl.dropboxusercontent.com/u/96935524/Datormusuem/TD_Systems_Inc_-_9…
, page 5 describe the connector.
Thank you!
QDT is the disk tape, yes. Conversion between
different models is a
matter
of accessing the serial console and enter a magic
word and then a code
for
the type of board. The PAL is pure address
decoding so you could have QDT
enabled while the PAL is QTO for example.
Now I'm confused, Zane explicitly said that a new PAL is required, did
come to some other conclusion?
> I also found some other interesting cards,
two Viking UTO, which I
> interpret as Unibus Tape Only. Would these be possible to convert to
accept
disk?
I think that the software / PAL is identical in these two. It is just a
matter of the bus interface logic that differs. Go ahead and try! I am
sorry I have no ability to program GAL / PALCE chips at the moment. 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?
I don't really know. But I have a CDU-720/M board which we could try to
copy the firmware from. Mattis:
If you want you can borrow and dump the 4.3 ROM if you like.
Yes, that would be nice!