17 Jun
2013
17 Jun
'13
9:40 a.m.
On 17 June 2013 04:40, Pete Turnbull <pete at dunnington.plus.com> wrote:
Yes, there is. DEC didn't sell 22-bit BDV11s as
such, presumably
because by the time it mattered, there were other options. But there's
an ECO that can be easily done as a field mod: ECO M8012-ML005.
One of the DEC module lists on the web lists that a BDV11 with board
revision E or higher already has said ECO applied to it.
How common are 22-bit capable BDV11 modules, per chance?
Well, as you know, you'll never be able to use PMI
memory with the
backplane you have, but you won't with a KDJ11-A either, regardless of
backplane. Also, if yours is a -BF, it's got an 18MHz clock[1], whereas
all KDJ11-A are 15MHz. So, no, I'd say it wasn't a good idea. Get some
reasonably fast Q-Bus memory, or get a different backplane if possible,
and /then/ get some PMI memory (presumably what you have isn't PMI memory?)
Yes, I know that I wouldn't be able to use PMI with the selected
backplane, nor with a KDJ11-AC. I also have no will to deal with PMI
memory or systems with PMI memory at all any way. I have no memory at
all, actually in the system so far. All I've got is that KDJ11-BF CPU,
a naked H9275A backplane, and am in the process of getting a CMD
CQD-220A/TM. But more on this later on in the e-mail...
As I'm trying to recreate the PDP-11 system I "lost", I'm trying to
stick with the equipment that would work best in a BA11-N box. Which,
in this case, is an H9275A backplane, as opposed to the H9278
backplane of the BA23.[1][2]
So, in this case, the 11/83, KDJ11-BF is *NOT* worth as much to me as
a KDJ11-AC.
That's why I'm openly asking whether "downgrading" from an 11/83 w/FPU
to a dual-wide 11/73 with FPU, a boot-ROM board, and a DLV11-J would
be a worthwhile trade to anyone. If anyone feels like that's a bad
deal (for me), I'm also looking for the "rest" of a PDP-11 system, by
which I mean a BA11-N box or a bare H786 power supply (the PSU for the
BA11-N), alternatively, I'm in the market for memory (MSV11-QC, which
I would be willing to pay for, but not $NEEDTOSELLMYSPLEEN). There's
other things I'm looking for as well.[3]
In any case, thank you very much for your response.
Cheers,
Christian
[1] As I mentioned I'm trying to replace my old PDP-11 system which
was, ahem, "lost." So I'm trying to get a BA11-N box, mostly because I
find I don't like the aesthetic of the BA23 box. Though I do find the
BA123 nice... if rather large.
[2] Which an H9278A (BA23 backplane) can fit into a BA11-N, but in
that case, I "lose" a row of QBUS slots, as the H9278A is only 8 rows
long versus the H9275A's 9 rows. Plus, there's the fact the H9278A has
three rows of Q22/CD and five of Q22/Q22 serpentine, whereas the
H9275A is completely Q22/Q22 serpentine (means a more densely packed
system, since I don't even want to deal with PMI at all; plus it is
compatible with KDF11 processors, without wasting space).
[3] I'll include the list of "things I really, really want" right
here, for future reference:
1. BA11-N box (all white, "PDP11/03-L" bezel wanted), or H786 power
supply (the PSU for the BA11-N).
2. Memory; MSV11-QC (M7551-C*) preferred, any non-PMI memory accepted,
as long as it's at least 2MB.
3. DRV11-J (M8049) quadruple 16-bit parallel interface.
4. LPV11 (M8027) Centronics lineprinter interface.
5. DHQ11 (M3107), any number up to four; DHV11 (M3104) also
acceptable, but the DHQ11 is much preferred
6. DELQA (M7516) Ethernet