PDP-11 Memory

allison allisonportable at gmail.com
Sat Jan 12 15:30:30 CST 2019


On 01/12/2019 04:14 PM, Bill Gunshannon via cctalk wrote:
> On 1/12/19 2:25 PM, allison via cctalk wrote:
>> 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.  
> My 11/23+ is in a box labeled PDP-11/23PLUS on the front with
> three toggle switches.  :-)  It has a 9276-A backplane labeled
> OPTION 11/23B. It is a 9 slot, Q22 A-B-C-D .  That's the home
> for my next system which will (hopefully) have 2 meg of memory,
> a DEQNA and an Andromeda Card for a small hard disk and 8" floppy.
BA11 box with one of the usual two common backplanes or standard BA23.

Problem with DEQNA is what OS?  RT11 does nothing with it.  RSX-11
I don't have a recent enough version so its often unused/

> I also plan on another small 11/23 with 128KW of memory and an
> 18 bit backplane so I can use the RX02 emulator.  And, probably
> an Andromeda in there, too
>
>
> To bring my part of this discussion to an end, I now have a BA23
> MicroPDP box with an 11/73 CPU, 4 meg of memory, DHV11 for eight
> serial lines (probably only use one to talk to a TU58 emulator
> but the DHV11 was just sitting there looking lonely) a DEQNA
> and a CMD SCSI Controller set for 6 disks and one tape.  Only
> thing it lacks at this point is software.
The TU58 like a responsive IO a DLV11J is a better choice for console and DD
and works best if first card after the memory (early in the interrupt
grant chain).
The simulators are faster than tu58 so it makes for fewer retries.
I use DHV11 for terminal and modem lines (slower stuff).
> On to my next project.
>
> Thanks for all the help.  I had forgotten just how much fun
> real computers were compared to PC's and MAC's.
Yes they are.  Their performance without all the gui gunk is often a
suprize
to many that have not worked with them.

Allison
> bill



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