Copyright (c) 1994 Wilko Bulte
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$FreeBSD: head/share/man/man4/fdc.4 60445 2000-05-12 08:36:36Z phantom $

.Dd August 31, 1994 .Dt FDC 4 .Os FreeBSD .Sh NAME .Nm fdc .Nd PC architecture floppy disk controller driver .Sh SYNOPSIS .Cd "device fdc0 at isa? port IO_FD1 flags 0x1 irq 6 drq 2" .Cd device fd0 at fdc0 drive 0 .Cd device fd1 at fdc0 drive 1 .Sh 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 .Sq 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.

p 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 .Ql 0x1 to pretend a 1.44 MB floppy drive as the first unit, without asking the CMOS for it.

p The flags value .Ql 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 .Dv FDC_YE is set, and defers device probing.

p 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 .Ql 0x4 . .Sh FILES l -tag -width Pa -compact t /dev/fd* floppy disk device nodes t /dev/fd*.<size in kB> floppy disk device nodes where the trailing number indicates the floppy capacity t Pa /sys/i386/conf/GENERIC sample generic kernel config file t Pa /sys/isa/fd.c floppy driver source .El .Sh SEE ALSO .Xr fdformat 1 , .Xr disktab 5