3 Sep
2018
3 Sep
'18
8:46 a.m.
On 09/03/2018 07:58 AM, Al Kossow via cctalk wrote:
One thing I noticed that made me nervous is looking at
the code there is no
checksum on either the sector address or data fields on the floppy. I made an
image of a floppy that I bulk-erased and initialized this morning, and all you
see are the sync bytes and data, no trailing data where a crc would be.
Looking at the ROM code disassembly, that certainly appears to be the
case. Perhaps the attitude was "if you want to check your data,
include a check in the data yourself". It wouldn't be the first time
that this was done.
Contrast with the Moto app note here for an 8" 3740-compatible setup
using the 6852:
http://www.bitsavers.org/components/motorola/6800/exorciser/AN764_A_Floppy_…
I recall that a friend had a KIM-1 with the KMISI expansion and a single
SA400 floppy disk drive. I don't recall the details, but getting
reliable operation was nearly impossible.
--Chuck