PDP-11 Memory

[allison]

On 01/12/2019 12:29 PM, Pete Turnbull via cctalk wrote:
> On 12/01/2019 01:24, Zane Healy via cctalk wrote:
>
>> I’m pretty sure you could get the /23+, /53, /73, /83, and /93 in
>> either a BA23 or a BA123.  I have an actual badged BA23 pedestal for
>> my /23+.
>
> I'm fairly certain all microPDP-11/23+ systems were only sold in BA23
> boxes, and I think microPDP-11/73 and the later, cheaper, cut-down
> 11/53 were as well.  But almost all the 11/83 systems I've ever seen
> were in BA123 boxes, though they did sell some in BA23 pedestals -
> I've got one.
>
Pete,

Your right the 11/23+ showed up on a lot of boxes but not the BA123
though it would fit.  The  BA23 as the micropdp11 or 11/53..  names and
models were a large jumble.  The J11 based CPU were showing up int BA123
as the later ones had PMI and a natural for the 123 as anyone
using J11 likely wanted storage, memory and space for it.  

Not not all of the dual width 11/73s were slow chips only that the were
run at 15mhz.  No advantage for faster as Qbus transactions
are slower for memory so the PMI versions were faster by default.

My BA23 (micropdp11was upgraded to microVAXII by me before DEC left me
and the machine next to it under the desk was VIDSYS: a
MicrovaxII GPX They both came home with me on last day.   The BA23 was
put back to the micropdp11 config and VIDSYS: remains though
with larger disks.  I also have a rack based system (11/73 CPU) and
multiple BA11 series mostly 11/23(various flavors) based but have the
11/2 board and LSI-11.   Even An H11 backplane with LSI-11 and Heath ram
and IO.

While there were many sold systems and a larger number of supported
systems Qbus PDP-11 was more mix and match than most any
and the early Qbus microVAX series did that for a while. 


Allison