FD INT FD - reserved for user interrupt
FD INT FD - DoubleDOS - ???
FD INT FD - Sanyo MBC-550/555 - IRQ5 - FLOPPY DISK CONTROLLER
FD INT FD - TFPCX - INSTALLATION CHECK
FD01 INT FD - TFPCX - TEST FOR CHARACTER WAITING
FD02 INT FD - TFPCX - GET CHARACTER
FD03 INT FD - TFPCX - OUTPUT CHARACTER
FDFE INT FD - TFPCX - GET VERSION