Date   : Tue, 22 Aug 1989 21:21:24 -0500
From   : mknox@emx.utexas.edu (Margaret H. Knox)
Subject: BDOS Guru for CP/M-68K

Jon,  you are looking for the right thing, in the wrong place.

The tables that (SHOULD) control the disk size and configuration
are the DPH (disk parameter header) and DPB (disk parameter block).
They are located in the BIOS, which is unique to each machine type
you are using.  The BDOS and CCP doesn't change from machine to
machine (at least, not for a particular version of CP/M-68K).

You can get SOME idea of the DPH and DPB from the DSK: display of
the STAT command.  To really look at the tables you need to do
the following:

       Bring up DDT

       Punch in a little program to do a SELECT DISK

               BIOS function 9

       The value returned in Reg. D0.L is a pointer to
               the DPH.  Eight words into the DPH is a
               pointer to the DPB.  Pretty much everything
               the system knows about your disk is
               contained in these two tables.

If you have source to the BIOS, modifying it for a bigger disk
(or partitioning it) is trivial.  If not, it can be a challenge.
One problem is that the CSV and ALV may need to be increased 
in size for a bigger disk.

For further information, check pages 24 and 40-45 of the
CP/M-68K SYSTEM manual (note: page numbers may vary, I am
looking in an old manual).

                       Luck