Date   : Wed, 24 Sep 1986 16:41:10 GMT
From   : Fred Bowen <fred%cbmvax.cbm.uucp@BRL.ARPA>
Subject: MFM on C1571

        I have recieved several requests for  information  regarding
        the creation of MFM-formatted disks using the Commodore 1571
        disk drive.  Hopefully this is enough to get you started.  A
        new FORMAT.COM file for C128 CP/M 3.0  should  be  available
        pretty soon-  watch your favorite BBS for it.

        Please refer to the 1571 Disk Drive User's Guide, Appendix G,
        page 101, for a complete description of the FORMAT MFM  burst
        command. The table below contains the data required to create
        a particular MFM disk format.  MD  and SS are given as binary
        values; the rest are decimal:


                 FMT         MD         SS      IL   N    LT   NS

             Epson QX10   01100110   10000001   0    2    39   10

             Osborne DD   01000110   10000001   0    3    39   5

             Kaypro II    01000110   10000000   0    2    39   10

             Kaypro IV    01010110   10001010   0    2    39   10

             IBM SS       01000110   10000001   0    2    39   8

             IBM DS       01100110   10000001   0    2    39   8



                MD   is the Mode                      byte 2
                SS   is the Starting Sector number         3
                IL   is the Interleave                     4
                N    is the Sector Size                    5
                LT   is the Last Track number              6
                NS   is the Number of Sectors              7



        The following BASIC program  demonstrates  how  a  FORMAT MFM
        command can be sent to a 1571 drive:

     10 OPEN  15,8,15
     20 PRINT#15,"U0"+CHR$(102)+CHR$(129)+CHR$(0)+CHR$(2)+CHR$(39)+CHR$(10)
     30 CLOSE 15

        The example above formats the disk in unit #8 using the Epson
        parameters.  Of course, you must still install the  necessary
        boot and directory sectors to make your DOS (CP/M) happy. The
        higher-level 1571 DOS commands,  such as Load, Save, and Dir,
        will never be happy with non-Commodore formats,  needless  to
        say, right?
-- 
Fred Bowen                     uucp:   {ihnp4|seismo|caip}!cbmvax!fred
                               arpa:   cbmvax!fred@seismo.CSS.GOV
                               tele:   215 431-9100

Commodore Electronics, Ltd.,  1200 Wilson Drive,  West Chester,  PA,  19380