27 Oct
2010
27 Oct
'10
1:39 p.m.
On 10/27/10, Ian King <IanK at vulcan.com> wrote:
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
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