Compupro System Support 1
Dual IDE CF (as Drive A and B)
ZFDC (with 5.25 and 3.5" disks as C and D)
I am now modifying my BIOS to allow for using a 1.44mb 3.5" diskette on my ZFDC. Looking at the Disk Parameter Header in the HFL3.ASM file I have referenced the proper Drive Parameter Table (CPM144) but there is one piece still missing.
It is what CPM3 refers to as the 'Sector Skew Macro
' for this format disk. Here are the two formats that John has included in the original files for 8" and 5.25" drives:
SD128$trans: skew 26,6,0 ;8" sector skew (Note first sector is 0)
DD512$trans: skew 16,4,0 ;5" sector skew (16 = 8X2)
I will need something like this:
CPM144$trans: skew 36,???,0 ;3.5" sector skew (36 = 18 sectors per track X 2 sides, sector count starts with 0)
The part with the ??? is what I need and described here in the CPM System manual:
The SKEW macro generates a skew table and requires the following parameters: the number of physical sectors per track, the skew factor, and the first sector number on each track (usually 0 or 1).
The form of the SKEW macro call is label: SKEW ?secs,?skf,?fsc where:
is the number of physical sectors per track;
is the sector skew factor;
is the first sector number on each track.
So, what do I need for the sector skew factor?