22 Jun
2015
22 Jun
'15
11:18 a.m.
The 3 bergs to unibus was used in the RK8-E, the unibus end plugging into
the first physical drive.
Between unibus backplanes were always M920, M9202, bus margin jumpers,
which i can't remember the part numbers, and various Albe and other non-dec
options. The cable was always a BC11A-XX, i think 2 to 25 or maybe 50 feet.
This is from the PDP11 world. i never played with the 725, 730, or 750.
On Mon, Jun 22, 2015 at 11:23 AM, John Wilson <wilson at dbit.com> wrote:
On Mon, Jun 22, 2015 at 11:46:08AM -0400, Noel Chiappa
wrote:
UNIBUS
I've
seen M9014s only at the far end of the UBAs on a KS10, so it
wasn't taking the place of a BC11.
??? If it wasn't take the place of a BC11 (i.e. proving a path for the out), what was it doing?
OK then I guess it *was* taking the place of a BC11. :-) I just meant it
wasn't jumping directly from one DD11 to another, so the "source" end
really was three Bergs, not a DD11 slot. I've seen that done only with the
fancy flexprint cable, not two paddles and three ribbon cables, so I was
kind of assuming that there's some impedance-matching (etc.) problem with
using ribbon cables for more than one hop. But then again ... I chose the
digital version of EE as my major precisely because I knew I'd flunk Fields
and Waves. Transmission lines are black magic as far as I'm concerned!
John Wilson
D Bit