Junkbox CP/M system? - test-drb@ccmp.vtda.org

24 Apr 2007

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Subject: Re: Junkbox CP/M system?
   From: "Chuck Guzis" <cclist at sydex.com>
   Date: Tue, 24 Apr 2007 11:07:20 -0700
     To: "General Discussion: On-Topic and Off-Topic Posts" <cctalk at
classiccmp.org>

On 24 Apr 2007 at 10:12, Allison wrote:

  At a minimum.  FDC interfaces are more involved
as the interface has to 
 include data and drive interfaces unless one can find a chip like 2793
 or 37C65. 
My personal favorite is the WD1770/1772 series.  It doesn't do 
500Kbps drives (no big deal for CP/M); interface logic is very 
minimal.  Very simple to program; a 4MHz Z80 should be able to keep 
up with the data transfer without breaking a sweat. And it fits in a 
reasonably small (28 pin) DIP package.

But a minimal system might incorporate nothing more than a PIIO or 
SIO and simply pass mass-storage requests and console I/O over the 
same path to a PC using a formatted message scheme.   Makes the CBIOS 
coding a walk in the park. 
If the system is 32k eprom with shadow, 1770/72 SIO, CTC and 64k of ram
it's called a AmproLB. ;) Great little system on a board. the LB+ adds a
5830 SCSI interface and that makes SCSI hard disk possible.

...
 Or, one could build the Z80 onto a PC prototype board
with its own 
local memory as a coprocessor and conduct mass storage and console 
I/O over a pair of I/O ports.  For many, that may be the best of all 
worlds as it relieves one of the problem of terminal and disk 
interfacing, power supply and enclosure.  Of course, the folks who 
want to put their project into a mahogany case with glass front may 
not be taken with this idea. :) 
That would be identical to the DecmateII (and III) CP/M APU board.
the board is a Z80, 64k of ram and two ports.  The DECmate does disk 
and display work for it.  The Z80 APU for the PRO350/380 is similar.
It's been done more than once on the ISA bus (PC).

As to the wood and glass case.  Anything fits inside that! ;)

Allison