< How many gates is a single chip processor going to use? And how < expensive is an FPGA that size. Or are large PALs a better choice < (free tools for AMD/Vantis MACH series, and Altera's entry level < parts) Figure well in to the 10000+ region. The PDP-11 looks simple but it's not! < What to use for a system. If I use a QBus based system (I have < several available) what are the timing requirements? Is there < a doc for this? Or Unibus? Or (my current favorite) Socket-7... Least significant consideration. First the chip/chips. < What architecture? Microcoded or gates? Microcode requires an < assembler, but might be quicker in the long run. Microcoded, all of the chip level 11s are (LSI-11, F11, T11, J11). < And when its all done, what is it really good for? How many < "hardware hackers" are interested in building CPU boards, and < are willing to share the cost of laying out and manufacturing < PCBs? Look a any PDP-11 ask that question, theres your answer. <I will probably make a stab at it, but depending on life, might not <ever finish... It's doable, the docs needed are commonly available. Costly. Allison