An update on my project, now permanently dubbed HoneyPi.
Marcel and I met up and pooled our resources, hardware and skills, so the project is definitely on. We now have enough memory and logic boards for the CPU and also enough switches and button tops to construct the control panel, although some buttons will be slim ex Univac buttons beefed up to the size of Honeywell buttons with a back moulding of clear acrylic. I've made one prototype just to prove that it works. I intend to use the remaining acrylic from the batch to make decorations for the Christmas tree; well, one must keep a sense of proportion.
Currently most of the work is putting together the infrastructure rather than logic. My checks on the PSU capacitors indicate that they are still in good condition after forty years out of use, which is a surprise. Having discovered how many supporting logic boards are needed just to get the core memory working, I am concerned about our shortage of backplane sockets. We only have 200, less than half the number used in the original model 201 CPU, so we may well have to pack the ICs that we are using onto custom-made boards to fit everything in. The memory support logic is the original second generation H200 stuff and we don't want to mess that around more than is necessary. At best HoneyPi is only going to be the illegitimate offspring of the H200, but should be identical performance-wise as we are working to original system timings and specifications as far as we know them.
Timing trials on the logic ICs gave a gate delay in the range 20-25nS, which will make designing logic around the 2 microsecond memory read/write cycle comfortable. We still don't know exactly what the ICs are, although we know their functions, as the Honeywell identifiers, AAAL4, AAAL5, AAAL6, AAFL1, AAVL1, etc are unhelpful but I have noticed secondary identifiers on some made by TI. These are 4295P, 4296P, 4297P and 4298P. I don't know of a 4200 series of ICs coming from TI in the 1960s but maybe somebody else does. Anyway, we know enough about them to use them.
Unfortunately I'm too busy (and probably incompetent) to set up the HoneyPi website at present but will get it under way when we've made demonstrable progress. Meanwhile it's all happening.