FDC(4)		       FreeBSD Kernel Interfaces Manual 		FDC(4)

NAME
     fdc - PC architecture floppy disk controller driver

SYNOPSIS
     device fdc0 at isa? port IO_FD1 flags 0x1 irq 6 drq 2
     device fd0 at fdc0 drive 0
     device fd1 at fdc0 drive 1

DESCRIPTION
     This driver provides access to floppy disk drives and QIC40/80
     tapedrives.  In /dev for each floppy device a number of minor devices are
     present.  The /dev/fd* devices with trailing alphabetic characters are
     used to indicate `partitions' on the floppy disk.	The /dev/fd*.<number>
     are devices that indicate the size of the floppy disk (so: 720kB, 1440kB
     etc). The latter are used for formatting disks using fdformat or for
     accessing different density disks in multidensity drive.  Example: 720kB
     disk in a 1.44Mb drive.

     Normally, the driver will ask the system's CMOS memory to obtain the
     floppy drive configuration.  Some machines do not store any form of a
     configuration value in their CMOS.  Use the flags value `0x1' to pretend
     a 1.44 MB floppy drive as the first unit, without asking the CMOS for it.

     The flags value `0x2' is reserved for PCMCIA floppy use, and should never
     be set in a configuration file directly.  It is internally handled in the
     driver if the compilation option FDC_YE is set, and defers device prob-
     ing.

     Normally, the device driver detects FDC chipsets that have an internal
     FIFO, and enables the FIFO on them.  There is a slight chance that this
     feature is actually misdetected (seen on an IBM Thinkpad 755c), so it can
     be turned off using flags `0x4'.

FILES
     /dev/fd*			       floppy disk device nodes
     /dev/fd*.<size in kB>	       floppy disk device nodes where the
				       trailing number indicates the floppy
				       capacity
     /sys/i386/conf/GENERIC	       sample generic kernel config file
     /sys/isa/fd.c		       floppy driver source

SEE ALSO
     fdformat(1), disktab(5)

FreeBSD 4.8			August 31, 1994 		   FreeBSD 4.8