Date   : Wed, 29 Oct 1986 13:53:00-EST
From   : prindle@nadc.ARPA
Subject: Query on CP/M disk formats

The Digital Research documentation on CP/M would seem to indicate that these
are the variables (the BDOS cares about) among different 5.25" MFM diskette
formats:

 . physical sector size
 . number of physical sectors per track
 . number of tracks on diskette
 . allocation unit size
 . number of directory entries
 . number of reserved system tracks
 . number of checksummed directory entries

Furthermore, the BIOS will undoubtedly need these facts:

 . origin of physical sector numbering on each track (0 or 1)
 . track numbering philosophy of physical sectors on a double sided disk:
       - both sides considered one track
       - even tracks on side 0, odd tracks on side 1
       - first half of tracks on side 0, second half on side 1
       - something even more bizarre

Are there any other parameters which are necessary to describe diskette
formats?
For example, are there variations within the format of a physical sector
itself (number of syncs between header and data, checksumming technique, etc)?
Thanks in advance,
Frank Prindle
Prindle@NADC.arpa