Patrick,
your BA11-M box (if it is the one from the video effects box you
described earlier) is probably the second-smallest Qbus box. There is
one with a backplane half as wide as yours, so you can put in only four
dual-height modules. This is the BA11-S, aka shoebox. You lost your bet
;-)
> I'm betting it's as small as QBUS comes. It's a Q/Q backplane, with 4
> quad-with slots. However, I could stick it into the backplane for my
> VAXstation 3200, which should be 22-bit Q/Q for most of the backplane
> (perhaps Q/CD for the top three quad-width slots).
Your BA11-M has a Q18 backplane, sufficient for 256kB or 128kW of RAM
(124.kW after subtracting the I/O page). Enough to get started with any
of the typical PDP-11 operating systems at least, and more than your
11/2 can support (it delivers only 16 address bits because it doesn't
have a MMU).
So, the limiting factor is the CPU, and then the amount of memory you
actually _have_.
However, a small system should be runnable on this box. What you'll
definitely need is at least one serial line to use as the console, so a
MXV-11, as suggested by Megan, would indeed be a good idea. Another
choice, if easier to get, would be a DLV-11J, which has four serial
lines, one of which can be jumpered to the correct CSR and vector to be
a console. Details available here upon request, if you cannot find them
by googling.
The disadvantage of the DLV11-J would be that it has no boot ROM, so
you'd still need something like a TEV-11, IIRC.
That ESDI controller (seems to really be ESDI, and not made by DEC), it
does not possibly happen to carry the proper boot ROMs around with it? -
Some third-party Qbus disk controllers do, but you may need different
ROMs or jumper settings for VAX or PDP-11 use.
> > >First, however, I'm sure I need DEC boot roms for it, or some other way
> > >to get boot code into it. Does anyone happen to have some laying around
> > >they could maybe send me an image of? Also, I'm on the lookout for a
> > >RLV12 and berg cable to connect to the RL02 I have sitting around here..
What ROMs you need may depend on the card (MXV-11, TEV-11, ...).
Unfortunately, I don't think I have any spares. However, since you have
a ROM board (hopefully, it can be convinced to decode the chip selects
to the right address range...), you may simply burn one of the publicly
available bootstraps into suitable chips. That's not a lot of wizardry,
once you know which device you want to support. It becomes more
difficult if you want to offer a choice to the operator, which is what
DEC's ROMs sometimes do...
Same for the RLV12: quite a good choice, given that you already have a
suitable drive, but no parts available from me. The older RLV11 would
not help because it needs CD wiring to interconnect the two boards it
consists of. The cable is not too critical at the controller side: get
any ribbon cable from your local store, perhaps they will even be able
to put the connectors on for you. But, they will certainly not have the
matching connector for the drive. BTW, do you have the bulkhead
connector for transition from the ribbon cable to the round drive bus
cable, and a terminator for the drive bus? (The terminator looks like a
connector with no cable attached, has a resistor array inside.)
> I've got a DECNA (i think) network
> adaptor in my VS3200 I could try to use. Right now, I'm wanting to try
> and re-use hardware I have instead of search for hardware that is hard to
> find.
Sure, you can expand later. That's what these boxes are made for.
If your network interface is plugged into a Qbus, it must be a DEQNA or
a DELQA (if you cannot find the M numbers through Google, look at the
board: the letters must be printed on it somewhere, etched in copper).
The DECNA is for the Professional machines (desktop PDP-11, as in Pro
350 or Pro 380, seen lately in this mailing list). The DEQNA is the
older board, which will not work in a VAX with VMS versions later than
V5.something. For PDP-11 use, either a DEQNA or DELQA will do, but
you'll need sufficient memory to support a network interface and
protocol stack.
> Also, is it possible/easy to change the M8044-BB board (8KW?) to have at
> least 16KW if not 32KW of memory? That'd be a nice upgrade for the
> machine if I can do it myself with 'stock' DRAMs.
I have no docs available here in the office, but I seem to remember that
the M8044 (MSV-11?) was available in several flavors (identified by the
letters after the dash) with different capacities, so it might be
possible. I'll look up more about this at home. There should be boards
to examine. Stay tuned.
I think Megan was thinking of a pretty comfortable machine, while you
first need to get started at all, after yanking the PDP-11 from the
video effects processor it was embedded in. Since I also started with a
rather small configuration, but have meanwhile grown to a total of three
PDP-11s (one UNIBUS, two Qbus) to fill a room, this must be possible for
you, too.
A remark about the power supply in your BA11-M: it is switch mode, but
does not require a minimum load current. With very low output currents,
it runs as a linear regulator, and with increasing load, it starts
switching, but with the load further increasing, it will slowly loose
efficiency (read: get hot). I try to keep mine only fairly loaded to
extend their life.
--
Andreas Freiherr
Vishay Semiconductor GmbH, Heilbronn, Germany
http://www.vishay.com
Received on Fri Jul 05 2002 - 10:15:05 BST