I have some scans of an old BYTE Magazine article
(July 1976 I think)
that details how to build a common interface for an arbitrary chunk of
core. I haven't really read it in-depth but I plan to someday. I can
put it online if anyone would like to see it.
It Would help lots more Dave if you dug out that disk drive.
The mv3500 is still pretty useless w/o swap space.
John A.