Pete Turnbull wrote:
On 02/08/2009
10:22, tiggerlasv at
aim.com wrote:
One can't really tell much without opening
the back panel,
but I will make a guess based on the photos provided in the auction
listing,
and typical system configurations from the period.
It would appear that this is a PDP-11/23+ system.
You mean a "microPDP-11/23". A PDP-11/23plus would be in a BA11-S
box. Same processor board, though, but very different boot ROMs.
I agree. DEC had some confusing (for outsiders) names to specify
systems which used the same CPU board.
This is based
on the basic "Micro PDP-11" medallion on the front panel,
and the 2-port cab-kit, which is standard for the 11/23+ only.
The badge could be any of the microPDP-11 series, as far as I can see.
But it is a 2-port cab kit -- well spotted (on single-port ones the
baud rate legend and selector are in the middle, with the DB25 at one
end and the LED displays at the other) so unless it's been upgraded
this is a KDF11 system, not a KDJ11.
I agree again!! Assuming that this cabinet kit is actually in use (it would
probably be 99.9% confidence since the 2 other 4 * DB25 cabinet kits
are never (at least in my experience) used for the console port. The 2-port
cabinet kit is unique to the M8189 CPU module. Unfortunately, it seems
to have been set up sort-of upside down so that the second DB25
connector can't be seen. So as Pete states, the CPU is almost certainly
the KDF11 in the M8189 module.
Most likely there is an MMU chip, but the FPU chip may not be present.
I see two
4-port cab-kits on there, which, based on the era
is most likely a DHV11, but it could be a pair of DZV11's as well.
Could even be a couple of DLV11-Js, though that's less likely.
Actually, I suggest that there is an even chance that there are a couple
of DLV11-Js, but there is insufficient detail to see the pins in the cabinet
kits. All 3 cabinet kits for the DLV11-J, DZV11 and DHV11 look
about the same, but the pins are different. An enlarged view showing
which pins are sticking out of each DB25 would be helpful.
There is a
lone connector in one of the "A" slots,
which could be just about anything. It sort of looks like
the LPV11 cabinet kit with the 37-pin connector,
but that is just speculation.
Could be; I thought about a DLV11-E or a DPV11, but the connector
looks too big for those. Maybe a TQK25 kit, I can't remember what the
connector on those was.
I have an extra TQK25 cabinet kit in the extras box which looks as
identical as possible to the light blue 50 pin centronics connector
shown. While it might be for something else, the TK25 is also
appropriate for the M8189 CPU. About 20 years ago, I also
used the TK25 as my primary backup, so I still have that hardware
around.
The RX50's
tell you that there should be an RQDXn controller
installed (most likely an RQDX2) which might also indicate
the presence of an RD52 or RD53 disk drive behind the front bezel.
If it were an 11/23 variant it would much more likely be an RQDX1, but
that's very similar.
Difficult to say which RQDXn is present, but almost certainly one of
them since there is an RX50. And which hard drive RD5n is present
is also impossible to identify.
If anyone actually wants to bid on the system, taking off the front
bezel is the easy part. The back plate to the backplane to identify
the other boards is also easy, but takes a few minutes longer.
Notice that there was no guarantee that the system is still working,
just that is was working when it was last powered down.
For anyone who wants a first PDP-11 system, this seems not too
bad, but the shipping will be very high. The BA23 is heavy enough
to cost more for shipping than the system itself. So if local pickup
is not possible and the total cost is important, check for all extra
costs first.
Sincerely yours,
Jerome Fine