7 Jun
2005
7 Jun
'05
2:49 p.m.
On 6/7/05, Paul Koning <pkoning at equallogic.com> wrote:
You have to find the product name that goes with the
board.
That's the only way to be sure.
Apart from the obvious "if it's hex it must
be Unibus" there isn't a
surefire way to tell things apart.
Except that it _might_ be from a PDP-11 memory bus, _not_ Unibus (like
the DRAM cards fo r the 11/70, 11/725, 11/730, 11/750...) or part of a
peripheral (RK611) or OMNIBUS (compare the visual appearance of, say,
a DZ-11 and an RL8A - they _are_ different, in distinguishable ways,
but a novice might throw them on the same pile).
About the only thing that is true is that "single or hex must not be
Qbus". Everything else is up for grabs.
Some heuristics may work: single height boards show up
in old Unibus
options (e.g., M105). If a dual height board is densely packed with
stuff, it's probably QBus, since dual height Unibus related modules
are also early modules and will have loosely packed small TTL parts on
them.
That is a good technique for a first-order approximation. Sometimes,
that's as far as you have to go.
-ethan