PDP-8s and -10s

[William Maddox]

--- William Donzelli <aw288 at osfn.org> wrote:

> Is there a good reason why DEC did not use the PDP-8
> architecture in the
> PDP-10, for proper channel controllers? Cheap,
> versatile, sixbit, and when
> the KA10 came out, already designed. I would have
> thought it to be an
> obvious "drop-in" solution.

DEC believed that DMA ("data break") was a more
cost-effective solution than IBM-style intelligent
channels, going all the way back to the PDP-1 -- at
least that is the impression that I got from the
retrospective papers in "Computer Engineering: A DEC
View of Hardware Systems Design".  

--Bill