One more circuit, stand alone PROM, EPROM copier with blank check and compare facility. In this circuit I am using a 12 bit address generator IC 4040 with 74245 8 bit transceiver IC but used as uni direction only. You can use any 8 bit unidirectional control latch like eg. 74373 etc. To compare the data i am using 74688. Now you can use your concepts for increasing the address bit, getting the output lateched etc.