UNIBUS PDP-11 memory expander card

Johnny Billquist bqt at softjar.se
Wed Jan 28 18:36:07 CST 2015


I am rather sure the cpu was left. But you really need additional bits in the par as well as actually addressing the extended memory. I probably should try to find the documentation for exact details here then. I might be able to track down the machine, but I haven't seen it in almost 20 years.

  Johnny 

Eric Smith <spacewar at gmail.com> skrev: (29 januari 2015 01:28:31 CET)
>On Wed, Jan 28, 2015 at 3:13 PM, Johnny Billquist <bqt at update.uu.se>
>wrote:
>> So, it also implies that the original MMU have to be removed. And
>that is
>> where you put the new card in.
>
>The PDP-11/34 "original MMU" is part of the base CPU and is not
>separable. Upgrading an 11/34 to 22-bit addressing would require
>replacing at least one or possibly both of the CPU cards with
>something else, in which case technically it's no longer an 11/34.

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