Inquiry on System Industries Qbus SCSI
tiggerlasv at aim.com
tiggerlasv at aim.com
Sun Apr 27 00:05:05 CDT 2008
I had put a few feelers out there a few months ago,
but was met with silence. It was ominous.
You could hear crickets chirping. ;-)
One company (Scottish Data Systems) may or may not
have the manual; I offered them like $50 + S/H for a real copy,
or $40 for an e-mailed copy, but never heard back from them.
I may have another source for the manual,
but I won't know for a few more weeks.
I have not been able to get a FULL description
of this board's capabilities.
I do know that at least half of the board
functions as a SCSI tape controller, with
TMSCP emulation, and have been able to get
that part of the functionality partially working.
Here is what I have so far:
SW-2 is a 10-position dip switch at the back of the board.
The switch settings are backwards from the norm.
Thus, OFF/OPEN switches are a logical "1".
1 = OPEN = OFF
0 = CLOSED = ON
Here is the bit decoding:
If you copy & paste this into a fixed font (not true type),
this should line up properly. I use Notepad in Windoze.
SWITCH 10 9 8 7 6 5 4 3 X 2 1
BIT 1 4 2 1 4 2 1 4 2 1 4
O O C C O C O C - C C
7 4 5 0 0
Note the missing bit in the address selection,
which correlates to the TMSCP addressing scheme.
The 50-pin connector towards the front of the controller
appears to be single-ended SCSI.
The connector set further back is probably
a differential SCSI interface, based on the DS75176's
I see directly behind the connector.
There are interrupt select jumpers at the back;
the jumper closest to the edge is BR4.
There is also a BEVENT jumper near the
back, center of the board.
I have no idea what the function of SW1 is.
There is a row of jumpers along the right edge,
which may be LUN selection.
I'm guessing the jumpers at the front of the board
are terminator / terminator power jumpers.
So far, I've been able to get the controller address set,
and have attached an Exabyte 8200 tape drive to it.
When I attempt to boot a tape, it does seem to send
commands to the tape drive, and the tape starts to seek.
After several seconds however, the processor halts.
If I boot RSTS/E, it hangs during INIT before
ever getting to a prompt.
Clearly, further poking around is required.
If anyone has any insight, it would be appreciated,
especially the current position of any of the jumpers
on your board, and settings for SW1.
I will keep you posted. . .
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