3 ms·
hello, imho. - as always: the FDD format was similar to the one of MS-DOS, because they used a hardware floppy-controller from the PC-ecosystem if i remember
by t312227 2y ago
hello,
imho. - as always:
the FDD format was similar to the one of MS-DOS, because they used a hardware floppy-controller from the PC-ecosystem
if i remember it correctly, it was a western digital 177x chip
* https://info-coach.fr/atari/documents/_mydoc/WD1772-JLG.pdf https://info-coach.fr/atari/documents/_mydoc/WD1772-JLG.pdf
the data-transfer to PCs was "somewhat" problematic, because the ST used SD - single density - discs with i think ~ 80 tracks, and about 720 k of available storage w/o using any formatting-"tricks".
and the PCs HD floppies hat twice the track-count and around 1,44 m of storage space.
to use HD FDD you had to "double" the step-impulse to the drive to be compatible to the SD drives of the ST.
just my 0.02€
ps. if i remember it correctly, the PC wanted to have some valid checksum in i think the last 2 bytes of the boot-sector ... the ST didn't care much about this!
pps. (commodore) amiga went into the opposite direction, and used some spare i/o ports from their custom sound & graphics-chips to control the floppy ... and implemented the format itself in software => which enabled the amiga to read most of the "foreign" floppy-formats at the time ... [timing hat to be compatible :]
- johndoe0815 2y agoNot quite, the ST floppies were DD (double density). One problem that could occur is that low-end ST configurations - especially the 260ST - were delivered with a single sided floppy drive (SF354, 1 side, 80 tracks, 9 sectors of 512 byte per track, giving 360 kB) instead of a double-sided drive (SF314 with 720 kB). PC HD floppy drives also have 80 tracks per side, but use twice the data rate (storing 18 sectors of 512 byte each per track) and thus require floppy disks with a different magnetic coating that can handle the higher frequencies. This can also cause problems with data retention and reliability when using 1.44 MB HD disks in DD drives for the ST. One problem with floppies formatted with early TOS releases (1.0 and 1.02) was that these used a Media Description Byte (offset 0x15) in the boot sector which confuses DOS/Windows system even though the file system format used is FAT12 or FAT16. This was fixed in TOS 1.04. Details at https://www-user.tu-chemnitz.de/~heha/basteln/PC/usbfloppy/floppy.chm/ https://www-user.tu-chemnitz.de/~heha/basteln/PC/usbfloppy/f...
- t312227 2y agohello, yes ... you are right, the FDDs were double-density / DD - its been a while :)) cheers