On 2018-06-18 04:00, Ronald Natalie <ron(a)ronnatalie.com> wrote:
Well, it is an
easy observable fact that before the PDP-11/70, all PDP-11 models had their memory on the
Unibus. So it was not only "an ability at the lower end", b
That’s not
quite true. While the 18 bit addressed machines all had their memory directly accessible
from the Unibus, the 45/50/55 had a separate bus for the (then new) semiconductor (bipolar
or MOS) memory.
Eh... Yes... But...
The "separate" bus for the semiconductor memory is just a second Unibus,
so the statement is still true. All (earlier) PDP-11 models had their
memory on the Unibus. Including the 11/45,50,55.
It's just that those models have two Unibuses.
Johnny
--
Johnny Billquist || "I'm on a bus
|| on a psychedelic trip
email: bqt(a)softjar.se || Reading murder books
pdp is alive! || tryin' to stay hip" - B. Idol