Richard (and Robert and Tony) are right.
There are two specific weirdities to the Kaypro format.
1) Kaypro uses a Western Digital disk controller v NEC 765 (or 8272) in
PC. Since Kaypro has ten 512 byte sectors per track, things are a little
crowded. The WD can start recording sonner after the index than the NEC,
and in the Kaypro format, they do. Sometimes the NEC based machines can
not read the first sector on a track.
The work-around is to either do your own formatting, with a longer gap
before the first sector than Kaypro uses, or to ignore the index
pulse. Ignoring the index pulse can be done temporarily by putting a
piece of opaque tape over the index hole of the jacket of the disk (a
write protect tab works great, but PLEASE make sure that it is on solidly
and doesn't fall off in the drive!), or for more frequent usage, add a
switch in the drive or in the cable to interrupt that signal.
2) The other weirdity (in DS Kaypro formats) is the head number fields in
the sector headers. One of the fields in the sector header contains the
side number of the disk. With the WD controller, you specify which head
you want to read or write with, and can ignore the value in the sector
header head number field. With the NEC controller, you specify which head
you want to read or write with, and MUST specify what value is expected in
the sector header head number field.
Kaypro, since they didn't care about what value was in that field, put the
wrong value in on the second side of the diskette (only relevant on DS
Kaypro formats).
Therefore, it is POSSIBLE to read and write Kaypro sectors on the second
side with a PC, but NOT using INT13 (unless you replace your INT13 with a
somewhat different one).
Since it is IGNORING that field, the Kaypro does not mind if you use
diskettes that have the correct value in the field.
The workarounds:
A) Use disks with the correct value in the field by NOT using the
Kaypro FORMAT program.
a. Modify the Kaypro format program (or write a new one) to put a
1 (the correct value) in the field on the second side of
disks.
b. Use other software, such as XenoCopy-PC on the PC, to format
the Kaypro diskette.
B) When reading or writing Kaypro diskettes on a PC, bypass INT13, and
talk directly to the hardware. Tell the hardware to look for a 0 in the
side 1 head number fields.
XenoCopy-PC uses workaround #A.
Early versions of Uniform used workaround #B, later versions stopped due
to too many PC disk controllers that wouldn't work with it.
--
Fred Cisin cisin_at_xenosoft.com
XenoSoft http://www.xenosoft.com
PO Box 1236 (510) 558-9366
Berkeley, CA 94701-1236
On Wed, 4 Apr 2001, Richard Erlacher wrote:
> This matter has come up before, in the context of Kaypro and other formats that
> are not precisely reproducible with a PC (NEC 765-based) controller. Apparently
> it's possible to format a diskette in a PC that can be read and written in a
> Kaypro but formatting the same format in a Kaypro produces results unreadable in
> a PC. I'm not sure of the details, not being a Kaypro owner.
>
> Dick
Received on Wed Apr 04 2001 - 14:51:58 BST