NAME
fdc
—
NEC765 compatible floppy disk
driver
SYNOPSIS
fdc0 at isa? port 0x3f0 irq 6 drq 2
(alpha, amd64, i386)
fdc* at sbus?
(sparc64)
fd* at fdc? flags 0x00
DESCRIPTION
Thefdc
driver supports the standard AT floppy disk
controllers. These include standard IDE, MFM, RLL, EIDE, ESDI and SCSI
controllers with floppy attachment, commonly encountered on many isa bus
machines, as well as the on-board floppy controller found on most UltraSPARC
workstations.
The standard names of a floppy drive will take the form /dev/fd{0,1,2,3}{,B,C,D,E,F,G,H}[a-p].
The first component of this path is the unit number, permitting a total of 4 floppy drives. The next component is missing for the default geometry (it would be A, but it is omitted for simplicity) and B-H for the other 7 geometry types the floppy driver supports. The last component of the path is the 16 partitions that a floppy disk can support.
The additional geometry types are as follows:
- `B' 1.44MB
- `C' 1.2MB
- `D' 360KB/AT (360KB disk in a 1.2 MB drive)
- `E' 360KB/PC (360KB drive)
- `F' 720KB
- `G' 720KB/x (720KB in a 1.2 MB drive)
- `H' 360KB/x (360KB in a 720KB drive)
The default geometry is the format specified in the BIOS, and is typically the largest supported format.
Some isa floppy controllers do not respond correctly to probes,
and the configuration file flags
field can be used
to specify a particular drive type, overriding the probed type. If the 0x10
bit is on, the low order three bits of the flags
field encode the drive type, as follows:
- 1 2.88MB
- 2 1.44MB
- 3 1.2MB
- 4 720K
- 5 360K
- 6 1.2 MB Japanese format
If the 0x20 bit is on, the drive will be attached even if it was
not found by the probe routine. These flags are ignored on
fdc
controllers not connected to an
isa(4) bus.
SEE ALSO
BUGS
The fdc
driver can interfere with other
isa(4)
controllers, namely some WD/SMC network controllers fail to work when the
probing mechanism in the fdc
driver probes for a
missing second floppy drive. In this case you should try recompiling the
kernel replacing the relevant line with fd0 at
fdc?
.