17 May
2023
17 May
'23
7:38 p.m.
> As for the target machine having a serial port,
one of the machines I
> want to get stuff onto is an Osborne 1A. The serial port on that is
> horrible.
On Wed, 17 May 2023, Robert Feldman via cctalk wrote:
For CP/M computers such as the Osborne, you can read
and write their
diskettes on an MS-DOS computer with a program like Media Master. KayPro
disks are harder, as there are problems formatting them on an MS-DOS
computer.
The earliest Osbornes were single density with ten 256 byte sectors per
track. I was able to write some code on TRS80 model 1 to read those.
Many PC FDCs, including the IBM 5150/5160, can not do FM/single-density.
Then Osborne came out with a "double density upgrade". The
MFM/Double-density Osborne disks are easy to do with PC, if you are
familiar with INT13h and INT1Eh.
But, my original stock 5150 PC could never read the original/early Osborne
disks.
Single sided Kaypro disks were not hard to do. Nothing special, other
than smaller than ideal inter-sector gaps to squeeze ten 512 byte sectors
per track.
But, the double sided Kaypro disks had an incorrect value in the head
number field of the sector headers of the second side! The WD controller
used in the Kaypro ignored that field, but the NEC FDC insisted on a
match. I tried some double-sided Kaypros, and found that they would work
fine with disks that had the correct value in the head number field. So,
I could format the disks in Kaypro double sided format on the PC, then
copy files to those pseudo Kaypro disks on the Kaypro, and bring themback
to the PC to read.
--
Grumpy Ol' Fred cisin(a)xenosoft.com