[cctalk] Re: OSI floppies (Was: Reading Old Floppies

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…