C128 and 8 MHz Z80

[RobertB]

On this page, there is a method to hack a faster Z80 in order to run CP/M faster.  See

https://github.com/ytmytm/c128-z80-8mhz

Truly,
Robert Bernardo
Fresno Commodore User Group - http://www.dickestel.com/fcug.htm
Southern California Commodore & Amiga Network - http://www.portcommodore.com/sccan

[BigDumbDinosaur]

On this page, there is a method to hack a faster Z80 in order to run CP/M faster.  See

https://github.com/ytmytm/c128-z80-8mhz

Truly,
Robert Bernardo
Fresno Commodore User Group - http://www.dickestel.com/fcug.htm
Southern California Commodore & Amiga Network - http://www.portcommodore.com/sccan

Yes, the Z80 itself runs faster, but I/O is still limited to 1 MHz operation, since it is the 8502 that is doing the work.  Also, the disk-intensive nature of CP/M means performance is hobbled by the relative-slow 1571 or not-quite-as-slow as the 1581.

The CP/M implementation on the C-128 leaves much to be desired in terms of performance.  Early on when I acquired a Lt. Kernal disk subsystem, I gave CP/M a go with it.  It definitely was faster than with use of a floppy disk, but not at the level I had seen on the native Z80 machines that were available late in CP/M's useful life.  I deleted the CP/M LU on the Lt. Kernal and that was the end of CP/M for me.