FDC(4) OpenBSD Programmer's Manual FDC(4)NAME
fdc - NEC765 compatible floppy disk driver
SYNOPSIS
fdc0 at isa? port 0x3f0 irq 6 drq 2 (alpha, amd64, i386)
fdc0 at mainbus0 (sun4c sparc)
fdc0 at obio0 (sun4m sparc)
fdc* at sbus? (sparc64)
fd* at fdc? flags 0x00
DESCRIPTION
The fdc 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 sparc and 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 ALSOeject(1), fdformat(1), ebus(4), intro(4), isa(4), sbus(4)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?.
OpenBSD 4.9 May 31, 2007 OpenBSD 4.9
