Regarding 800K floppies: Someone up-thread mentioned that the spindle speed varies, amongst other things, on the Macintosh floppy drive. This is exactly correct and one of the major issues in converting from PC floppy mechanism to Mac floppy mechanism. The PC floppy mechanism has no provision for varying the spindle speed.
Outbound (anyone remember them) did it. They used Citizen brand PC laptop floppy drives in their laptop Macintosh clones. There's a circuit board between the Mac clone and the floppy mechanism though. On the circuit board there is a 37C765 floppy controller, a WD92C32 data separator, a little digital potentiometer, XP9103, an EEPROM and a 20 pin PLD. The external floppy version also has an 85C30 on board, suggesting that the Outbound's external comm bus is some flavor of serial ocmmunication -- maybe. Or it could be a bit of a copy of the HD20's hardware structure.
That same port could accept Outbound's SCSI adapter instead of the external floppy. The SCSI adapter also has an 85C30 on board as the most upstream device. It's simpler than the floppy control board though. It only has an 53C80, an EEPROM and another 20 pin PLD on board -- oh and a couple or dozen transistors.
Outbound (anyone remember them) did it. They used Citizen brand PC laptop floppy drives in their laptop Macintosh clones. There's a circuit board between the Mac clone and the floppy mechanism though. On the circuit board there is a 37C765 floppy controller, a WD92C32 data separator, a little digital potentiometer, XP9103, an EEPROM and a 20 pin PLD. The external floppy version also has an 85C30 on board, suggesting that the Outbound's external comm bus is some flavor of serial ocmmunication -- maybe. Or it could be a bit of a copy of the HD20's hardware structure.
That same port could accept Outbound's SCSI adapter instead of the external floppy. The SCSI adapter also has an 85C30 on board as the most upstream device. It's simpler than the floppy control board though. It only has an 53C80, an EEPROM and another 20 pin PLD on board -- oh and a couple or dozen transistors.