Jerome Fine wrote:
>If the 11/23 is a dual board, you may have a bit of a problem in the BA23
>since the BLUE box was designed with boot boards that might not be
>compatible with the BA23.
Because the BA23 has termination, or because it's a 22-bit backplane, or
something else? The bootstrap is an M8012-YA (BDV11)
terminator/bootstrap, and neither it nor the other option cards (M8044-HD
64Kb, DSD floppy controller, M8043 async) connect the pins for bits 18-21
(BC1-BF1). The CPU is a dual-width card, and has no apparent revision
marked, so I guess I should assume it is the 18-bit version.
All else being equal (i.e. provided it works) I'd prefer to keep the
system in its original enclosure anyway, that is, more or less close to
its previous working configuration.
>> As I found it, the arrangement of cards has gaps, unless the backplane is
>> *really* weird. The backplane itself is MDB model MLSI 40328 -- anyone
>> know the layout?
>
>If I remember, Transduction used a hex back plane modified to be a Qbus
>interface with a serpentine use of the "extra" slots. But I can't remember
>the order.
For the archives, this backplane is 4x8 and turns out to have the 'usual'
serpentine configuration throughout; i.e. the same arrangement as slots
5-12 in a BA123. It is 18 bit; pins BC1 - BF1 are not connected.
>> The only non-obvious card in the system is an MDB DR11B... is this a
>> parallel interface?
>
>Probably. MDB boards were usually named by their DEC counterpart.
Seems plausible that it is a 16-bit parallel I/O card, from the 74173s
attached to the headers. Anyone know whether this is DRV11-B compatible
(it is a qbus card, of course), or otherwise have any programming
information for it? From time to time I'm tempted to buy some old PeeCee
just to get a usable parallel port, but I'd much rather use a PDP-11 :-)
--
Kevin Schoedel
schoedel_at_kw.igs.net
Received on Thu Aug 03 2000 - 23:09:57 BST