Dec boards- what are they?

[Ethan Dicks]

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