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Re: Microsoft Z80 Card

Paul Schlyter wrote:

In article <441b5b3b$0$7748$9b4e6d93@newsread4.arcor-online.net>,
Linards Ticmanis  <ticmanis@gmx.de> wrote:
4 - does the apple CP/M work with SCSi drives? ( and the CFFA, if i manage to get one ) or am i stuck with just floppies? 

No idea, sorry. I'd guess not.



The standard Apple CP/M distribution supports only floppies, that's
correct.  However, when compared to other OS'es of that time, CP/M was
unusually versatile if you wanted to add a new kind of disk drive to
it.  Get a copy of the CP/M Alteration Guide e.g. here:

    http://www.cpm.z80.de/drilib.html

There you'll find descriptions of how to correctly set up the disk
parameter tables in CP/M's BIOS to make your new drive recognizable
by CP/M.  To that, you must add code which actually accesses your new
drive - naturally that is system specific and cannot be covered in
a generic manual.

Formatting a new drive for CP/M is easy: just make sure all the
sectors are there, then fill them all with hex E5 bytes.


Ouch--I had forgotten the need to write all sectors.  This is an
effort equivalent to a low-level format!  Clearly designed at a
time when that could be done quickly...

Would it be possible to do this incrementally in the driver? For
example, by clearing the remainder of every sector written to to $E5
and by presenting any unused sector as filled?  (I have a feeling
that this would require writing to every sector allocated in a block--
not a bad security measure in any case.  ;-)

-michael

Music synthesis for 8-bit Apple II's!
Home page:  http://members.aol.com/MJMahon/

"The wastebasket is our most important design
tool--and it is seriously underused."