How Big?

So how big is this project?   That is, will I ever finish?

You can't optimise without defining what it is you want to optimise (the objective function).   So firstly we need to define what "Big" means - is it:
  • area - that's important as I want one camera to see the whole state of the machine
  • component count - that's important as it's the main factor in cost and time
As most of the bulk components costs less than half a pence each and this project is going to be very time intensive to assemble, then I'm going to use the number of components as my measure of Big.   Resistors and diodes have two legs, transistors have three legs so I could (and earled it did) choose legs as the number to optimise.   But components dominate area and cost and correlate very very highly with legs, so the simplest is components.

As documented here, I was expecting 2 transistors, 12 signal diodes, one LED and six resistors per memory cell, 16 bit registers and about 8 registers.   That's 21 components per memory cell, or about 2700 components just for registers.   If I could get it down to 5 then that's only 640 and I have to design the ALU better...

The ALU looks like 13T per bit slice at the moment, plus two for the output buffer, that's about another 256T.

Now if I could get the instruction decode, bus select and memory logic into less than 256T then that would be much less than 1024T overall, which would be a great achievement.

This has to fit into one plane and be transportable, so no bigger than 1m x 1m (stuck to a decent bit of plywood with a carry handle).    It still seems doable right now.