Re: Can anyone help me with Apple CP/M

[shirsch@adelphia.net (Steven N. Hirsch)]

On Tue, 20 Jun 2000 22:24:22 +0000, Matt Jenkins <mdj@pacific.net.au> wrote:

>That's an interesting one. Does the boot drive have to become logical
>drive A: in CP/M ? It'd really complicate issues if this happened.

Not necessarily.  You just need to ensure that the BDOS logs to
whatever logical drive the BIOS maps as A:.  The AppliCard could boot
from a floppy, then log to a hard disk partition.

>Yeah I'm set on using the standard Unidisk setup.

In a previous life, I wrote a Unidisk CP/M driver for the Applied
Engineering Z80+ Card (Microsoft Softcard clone).  As a matter of
fact, I wrote the entire Z80 and 6502 BIOS and all drivers and
utilities.  Since the company is long gone, perhaps I'll unearth this
stuff and make it available.

>I wonder how amenable the Applicard would be to a crystal swap, faster
>RAM and a beefy Z80H ? It'd be interesting to see how far it could be
>pushed.

Been there.  Done that.  The biggest obstacle is getting DIP DRAM fast
enough to keep up with an 8Mhz. CPU.  IIRC, you need 100nsec. or
faster. This was not easy to come by in the late '80s.  There was also
a hardware mod to avoid some gate propagation delays.  Man, this is
going back some - sorry I can't remember the details.  I had an
Applicard overclocked to 11Mhz. with a selected Z80H and memory.

>I've got a Transwarp in me //e too, so maybe the I/O would be improved
>a bit by that, presuming the 6502 side software doesn't have timing
>issues.

This helps immensely with an Applicard.  Won't work at all with the
traditional Softcard.

>Ah, probably just shunted their BIOS into the 2nd bank so than the BDOS
>could load higher. I guess in that sense it's not really a 60k system,
>just a neater version of the 56k system, since the linear memory
>available
>to the Z80 doesn't really change.

Yup.  I used both memory banks in the AE Bios and some of the tricks
for switching and data-access were a bit tricky.

Feel free to bug me in private E-Mail if you feel the code for this
would help.

Steve