It would be very nice if Hardware designs allowed for RAM to be placed in the
Program EPROM sockets during development. Applied Microsystems charges several
thousand dollars for 128k bytes of Emulation RAM. If we could put a piggy back
board in the EPROM sockets and run a couple of jumper wires to bring R/W to the
piggy back, we could give the programmers lots of emulation RAM for cheap. 32k
by 8-bit SRAMS cost $15-20 quantity one. Four of them are needed to make
128k...so for less than $100, we can replace what Applied Microsystems charges
several thousand dollars for. 

I would like to see this feature added to PCB's as well as wirewraps if it
didn't cost to much. I imagine all that needs to be done is to make the EPROM
address space writable and bring the appropriate R/W signal to a buffer capable
of driving the new load. This signal would also have to be accessible to the
piggy-back board. Gary Stempler suggested a jumper pin as used on SystemI to
configure the progam space for 27128/27256. This could then be eliminated in
production.