home | help
FDC(4)			     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  configura-
     tion  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 probing.

     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 trail-
				       ing 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 4.11			 August 31, 1994			  FDC(4)

home | help