[tony duell]
:But there's very few similarities between (say) the PDP8,
:the PDP10 and the PDP11.
having read up on these, we'd beg to differ here. it seems to us that
all the pdps followed a very definite architectural pattern, with the
exception of the pdp11 which struck us as a major departure (the dg nova
has more in common with the early pdps than the pdp11, to our mind). ok,
so they weren't anything like binary compatible (well, between families
- there was the 5,8,12; the 1; the 4,7,9; the 6,10; and then the nova /
eclipse. all were basically accumulator-plus-memory architectures, it
seems, even the 6 and 10; all had simple, regular, but very powerful
instruction sets with minimal formatting and all instructions in one
word (if you view the 6 word size as 18 bits and call it a double word
machine :> ) - we can discern a very distinct family resemblance on the
way up.
the pdp11 marked a major change, from a 1-address to a 2-address
architecture. we aren't sure it was a good thing...
anyway, the pdp8 is much more similar to the 10 than either is to the 11.
-- Communa (together) we remember... we'll see you falling
you know soft spoken changes nothing to sing within her...
Net-Tamer V 1.08X - Test Drive