[Info-vax] OT: obscure PDP11 OSes (even more dinosaury)

[William Pechter]

In article <q0ek6PYsdXoN at eisner.encompasserve.org>,
Bob Koehler <koehler at eisner.nospam.decuserve.org> wrote:
>In article <5586381E.9040801 at spam.com>, Don North <idontwant at spam.com> writes:
>> 
>> The PDP-11/20, PDP-11/05 (aka PDP-11/10), and PDP-11/04 were MMU-less UNIBUS 
>> machines so they only supported a maximum of 56KB of memory. The UNIBUSes on 
>> these machines were 18bit address to be compatible with the UNIBUS,
>but of the 
>> full 256KB UNIBUS address space the low 56KB of memory could be
>addressed, and 
>> the upper 8KB of address space was the I/O page.
>
>   I think you missed the 11/34.  IIRC no MMU, only UNIBUS mapping
>   registers.  I/O space was 18 bit, but RAM was 16.
>

The 11/34 had an mmu.  The 11/04 did not.
-- 
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