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Re: More fun with Freed Z80

mdj wrote:

On Feb 16, 12:20 pm, Steven Hirsch <snhir...@gmail.com> wrote:


Intersesting... What's the status of this? I've yet to put my board
together, but I do prefer the idea of running it from ProDOS

I'm busy trying to piece together what I did to make that work.  It was done
as proof-of-concept for the CardZ180 project and never really polished up.
Instead of writing to the boot tracks of the disk, the setup program created a
DRIVERS file and a relocated PCPICPM.SYS.  You copy them to a ProDOS boot disk
(using a disk transfer utility to bootstrap yourself) and startup from there.
  The PCPI 6502 BIOS basically runs as a ProDOS SYSTEM program and, once
running, can use the filesystem services to better support transfer between
CP/M and ProDOS.  I have a utility called pdosxfer that's use to move things
back and forth.


So the CP/M CBIOS is implemented in 6502, and on the Z80 side there's
a "proxy" CBIOS that delegates this responsiblity back to the Apple II
host ?


The Z80 BIOS is a bit more than a proxy, but that's essentially correct.


I'd be interested in being able to use CP/M image files (hosted on a
ProDOS volume) as the actual "disk", rather than a partition or other
raw ProDOS device. This is similar to how I still run Apple Pascal -
using a hacked version of the Pascal Profile Manager that Willi and I
nutted out a few years back.
I think you'd find that quite slow. The ALS/DRI 128k CP/M card used that approach and file I/O was glacial. By allocating a contiguous partition you can operate at the block level and avoid a lot of overhead. 

Steve