Happy Birthday VAX 11/780 (influence of)

Ethan Dicks ethan.dicks at gmail.com
Wed Oct 27 15:39:41 CDT 2010


On 10/27/10, Ian King <IanK at vulcan.com> wrote:
>> But as usual, the question is: was really the PDP-11 first with these
>> things, or can you find earlier examples?
>>
>
> I do believe the PDP-11's use of memory-mapped I/O was original - at least I
> can't think of any earlier examples.  -- Ian

It's the earliest one I am aware of, but my knowledge of non-DEC stuff
before 1970 is admittedly full of gaps.

I started with the 6502 (in 1977), so I thought memory-mapped I/O was
"normal".  The 1802 was the first processor I used that had I/O
instructions.

So I guess since any processor that has gaps in its memory map _could_
have those gaps filled with memory-mapped I/O, the question is _did_
any implement it prior to 1969/1970?

-ethan



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