Grrr - !%#*^@# Kaypro!
Fred Cisin
cisin at xenosoft.com
Wed Aug 3 18:08:22 CDT 2005
On Wed, 3 Aug 2005, Allison wrote:
> Dave, your on track. The CHRN vlaues do not have to corrospond
> to actual head or cylinder. They do not even have to be in order
> on the media! The only limits on them are R must be 1 or greater
> (less than 255).
Which creates some complications with handling 128 byte sectors (R==0).
> My favorite format was sectors 1- 9 (512 DD) on side one and
> side two was 10-19 with H always set to 0.
Easily handled by 765, but not by Int13h.
I have to be careful to differentiate which complications are
due to the FDC chip, which to the FDC board/implementation,
and which are BIOS linitations.
Nitpick: don't you mean 0 - 9 on first side? Or did it actually have 9
sectors on one side and 10 sectors on the other?
I've seen disks with 10h and 20h in the H field.
My favorite was 1 in the H field for the first side and 0 in the H
field on the second side.
And, of course, there are some formats, such as Superbrain,
where the data (sector content) is inverted,
but the headers (CHRN) are not.
--
Grumpy Ol' Fred cisin at xenosoft.com
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