Ohio Scientific 6502 computer, with two 5.25 inch
floppy disk drives,
Shugart SA400 drive: 35 track, 48tpi
PIA/UART, instead of FDC chip.
"VERY soft-sector"
It is FM, at usual 125Kbps used on 5.25" single density, but, without
WD/IBM track and sector header format.
So, a flux transition board might work, or maybe even a "track read" of a
WD FDC. NEC "track read" is actually "multiple sector read", so will
not
work on other than WD/IBM track/sector format, without extra efforts to
FOOL the FDC into doing an actual track read (cf. reading Amiga on PC)
https://torlus.com/floppy/forum/viewtopic.php?t=1284
has some details on the floppy format!
"Each track has a track header, which is written and read approximately 1
ms after the index pulse, consisting of a 2-byte track start code,
followed by the track number in BCD, followed by a stop byte code. The
track header is followed by a software-defined gap.
"Each sector is indicated by a sector start code, followed by a sector
number byte, followed by the sector length, followed by the sector data
(the length in pages multiplied by 256 bytes), followed by a sector end
sequence. There is a software-defined gap between each sector."
https://osiweb.org/computes_gazette/Compute_n020_p136_OS65D_Disk_Routines_P…
https://osiweb.org/computes_gazette/Compute_n021_p118_OS65D_Disk_Routines_P…