FDC(4) BSD Kernel Interfaces Manual FDC(4)NAMEfdc — 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.
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/config/GENERIC sample generic kernel config file
/sys/dev/disk/fd/fd.c floppy driver source
SEE ALSOfdformat(1), disktab(5)BSD August 31, 1994 BSD
