3.5" Altair CP/M - test-drb@ccmp.vtda.org

16 May 2007

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Subject: Re: 3.5" Altair CP/M
   From: David Griffith <dgriffi at cs.csubak.edu>
   Date: Tue, 15 May 2007 15:33:55 -0700 (PDT)
     To: "General Discussion: On-Topic and Off-Topic Posts" <cctalk at
classiccmp.org>

On Tue, 15 May 2007, Grant Stockly wrote:

  I have a tarbell floppy controller card that has
been rewired to access
 3.5" disks using a standard PC 3.5" disk drive. [snip]
  What could be missing?  If the bitrate is fixed,
then is CP/M not writing
 standard sectors?  Rawread says "Address not found" and diskinfo says the
 drive is not ready. 
I take it you don't have access to a Unix machine?  The dd command might
be able to fish out something more from that disk.  Specifically, the
utility cpmtools is useful for writing to a variety of disk formats and is
easy to customize for new formats.

...
 From all I've read the controller is a a SD unit
and may be running at either the 8" SD rate or possibly the 5.25" SD rate
makig the disk at most 360k.
That 360k format is NOT PC compatable.  The OS used on the PC is not  a factor
as whatever you do required direct controll of the FDC even then some PCs will
NOT do the slower SD data rate.

Allison