Looking for info on National Semiconductor RAM board (VAX 11/730)

How would DEC know? These boards do not, AFAIK, have any form of machine-readable ID. All DEC could tell remotely was how much RAM was in the machine. And I would hope any Field Servoid could spot a non-DEC memory board if he was looking in the cardcage! Disablng the board would prevent it acting as a data storage area, but if there's a shorted buffer or something it could still mess things up. There is a common bus to all the memory boards, at least in the 11/730. And I know the machine will not behave normally if there are gaps in the physical memory space, quite whether it would run diagnostics in that case I do not know. So I guess you had better have all the DEC boards at the start of the memory space and if you want to make the 3rd party RAM disappear, disable all the boards. -tony