Building it on top of ProDOS might be fairly doable.
ProDOS provides an API for block-based file I/O that's fairly simple and supports multiple different drive types. On a 128k system you'd get a 64k RAM disk for free. It might fit nicely with the current code.
And ProDOS already lives in the bank-switched Language Card area, so there would be good chunk of main RAM to work with, a little under 46K from $0800 to $BF00.
Both of the currently supported platforms, C64 & BBC Micro, also had Z80 add-ons available which allowed running CP/M. I don't think the project is necessarily about it serving people better.
C128 CP/M is slow compared to other CP/M systems due to oddities of its implementation, but it works, it's native on the Z80, and with a 1571 you even get disk compatibility. In 80 column mode, it's certainly fast enough.
I think the point is that if your use-case actually needs stable CP/M, the original Z80 version running on an add-on card is more useful than a hobbiest port.
Old 8-bit systems still run many businesses just fine.
I'd rather run some critical part of my business on an Apple II with software that's had 30 years to eliminate every last bug than some IoT piece of crap.
A couple years ago I shut down Chicago's premier burger joint for an hour because I tried to pay with cash. Their IoT cash register locked itself and their fancy iPad based POS system refused to take any new orders. They were trying to figure out who to call in SF, had to @ them on Twitter for support.
It was ridiculous. Normalize running your business on small computer systems.
Running a business on an Apple II is at least as silly as running it on an
iPad since any kind of hardware failure is going to be harder to quickly resolve (unless you’re the kind of business that has electrical engineers to hand. But even then, it’s still not as quick as buying a new stick of RAM from the local computer store).
There is a sane middle ground between your experience and running CP/M on a 40 year old computer.
> software that's had 30 years to eliminate every last bug
Bugs can exist in hardware too. Plus I wouldn’t be so quick to assume that every last software bug would be fixed. For starters any bug fixes in that time could introduce new bugs. And there are often bugs that are time specific (like epoch overflows).
Sure and if you own a BBC Micro/Master you could do the same via something like the Torch Z80 second processor. The whole point of this project was to build CP/M for the 6502, most likely to scratch an itch which many of these comments seem to completely miss.
The guy wanted to see if it could be done on a 6502. Who said it had to be 'useful'? Why are you so sure your definition of 'useful' and his definition of 'useful' are the same here? Why does virtually every post on HN about someone's personal, possibly quixotic quest to do something for fun attract a pack of tech-Karens who tut-tut it with "well OBVIOUSLY you should have done something different than what you did. I should tell the Manager.".
IIRC, Apple IIc had an interrupt built-in, if that's neeeded.