Hi
I was thinking more along the lines of a hobbyist open hardware approach somewhat similar to what we did on S-100 or ECB.
Right now (AFAIK) there are no open hardware Multibus designs or the infrastructure to support it so any project involves Multibus basically means starting completely from scratch. For instance, board outlines, part libraries for P1 and P2, example schematics in KiCAD (open source) format, etc. All those things you would need to even start a project. Also there doesn't seem to be any much, if any, hobbyists building their own Multibus boards so there are skills and knowledge would need to be built up as well. Without a Multibus template each project has to carry all the burden and I think that suppresses a lot of people from even starting or considering their own.
I think your ideas are great for Multibus projects but I think they are more graduate level where I was thinking more like freshman introductory level projects to "prime the pump" and get things rolling. [I asked a similar question on the S-100 Google Group so I'll weave in part of my thread from there since it is similar]
What I am suggesting is more of a "crawl, walk, run" approach. IMO, there are really three basic kinds of boards for any parallel bus in rising order of complexity: IO, memory, and processor.
In order to get started with a something well documented and low risk technically but important from an infrastructure perspective. Like the simple IO board from Application Note AP-28A which is really just a pair of 8255 PPIs. Develop that board which would provide the board outline, connectors, and general schematic building blocks for later more sophisticated IO boards like IDE, serial, etc. Or maybe start with an even lower threshold like a prototyping board.
Once IO boards are working and reliable build static RAM and Flash ROM memory boards. Again, keep it simple as possible building on the lessons from the IO boards and build up that open hardware Multibus infrastructure.
Finally build processor boards starting with 8085, move up to 8088, 8086, etc. Once those are working then attempt the non-Intel processors or more aggressive designs like bus bridges, FPGAs, etc. People are doing stuff like that on S-100 now but only after many years of slow progress going up the ladder of complexity.
Obviously this is a big long term project but the model has worked at least twice in the past. Once with the ECB board collection and again with the S-100 boards. It is too big for a single individual and would require significant investment in time, effort, and money.
I would be happy to design a simple open hardware Multibus board and put the design out there but I am doing some "market research" first before I spend time on it. Multibus is different than S-100 and ECB in that those busses are dominated by hobbyists while Multibus systems are still in use in industry and in some cases commercially available.
There are things I'd be happy to do like build a KiCAD version of an IO board but not chase down other people to build it, buy boards, distribute boards, etc. In other words, for this to work there has to be some level sponsorship and group participation or it is just me pushing an idea no one else really wants.
I don't know what the level of interest is out there or what people's capabilities are. Maybe jumping to a PowerPC processor board is feasible as a first step but it seems overly ambitious to me and is way beyond my skill level.
Thanks, Andrew Lynch