At the time, the 8MB of dram we had cost us something like $20 or $30 (no, really... would have been cheaper for us to buy simms and desolder the chips).

There was no room for the other chips on the top of the board, and doing 2-sided SMT would have put up the build cost hugely. So we put the pads on there but never fitted chips. They've never been tested, but should work in theory.

We ruled out simms because of (a) space and (b) vibration.

Hugo