4 ms·
Its BASIC frontend was not really legacy, instead the CP/M environment was basically tacked on. It had an entire separate CPU, an actual Z80, for that purpose,
by anyfoo 6y ago
Its BASIC frontend was not really legacy, instead the CP/M environment was basically tacked on. It had an entire separate CPU, an actual Z80, for that purpose, but unfortunately running CP/M was almost unbearably slow (which was not really the fault of the Z80).
BASIC, in its upgraded version "BASIC 7.0" (compared to the C64's "BASIC 2.0") was quite obviously still the "main mode" and the one that supported all the C128's features.
However, there was also a third mode, a "C64 compatibility mode", which removed (almost) all of the new features and presented itself exactly like a C64 would, same ROM and all.
- glhaynes 6y agoWhy was running CP/M so slow? I never got to run it but I don't think of CP/M as being a particularly bloated/slow OS; but you say it wasn't the fault of the Z80. Something particular to the C128?
- anyfoo 6y agoI haven’t done any independent research (other than trying it out in a C128 emulator and concluding that it indeed feels very slow 8) ), but there is a detailed answer here: https://retrocomputing.stackexchange.com/questions/2361/why-does-the-commodore-c128-perform-poorly-when-running-cp-m https://retrocomputing.stackexchange.com/questions/2361/why-... The issue does not seem entirely clear cut, but from the looks of it, while apparently the newer CP/M 3.0 used there does seem a bit slower than earlier versions, the majority of the reasons seem indeed pretty specific to the C128.
- glhaynes 6y agoThis was so much more background than I’d dared hoped for! Thanks, really interesting. What a mess.