FD(7D) Devices FD(7D)

fd, fdc - drivers for floppy disks and floppy disk controllers

/dev/diskette0

/dev/rdiskette0

/dev/diskette[0-1]

/dev/rdiskette[0-1]

The fd and fdc drivers provide the interfaces to floppy disks using the Intel 8272, Intel 82077, NEC 765, or compatible disk controllers on x86 based systems.

The default partitions for the floppy driver are:

a

All cylinders except the last

b

Only the last cylinder

c

Entire diskette

The fd driver autosenses the density of the diskette.

When the floppy is first opened the driver looks for a SunOS label in logical block 0 of the diskette. If attempts to read the SunOS label fail, the open will fail. If block 0 is read successfully but a SunOS label is not found, auto-sensed geometry and default partitioning are assumed.

The fd driver supports both block and raw interfaces.

The block files (/dev/diskette*) access the diskette using the system's normal buffering mechanism and may be read and written without regard to physical diskette records.

There is also a raw (/dev/rdiskette*) interface that provides for direct transmission between the diskette and the user's read or write buffer. A single read(2) or write(2) call usually results in one I/O operation; therefore raw I/O is considerably more efficient when larger blocking factors are used. A blocking factor of no less than 8 Kbytes is recommended. See the Notes section, below, for information on the number of sectors per track.

For 3.5" double-sided diskettes, the following densities are supported:

1.7 Mbyte density
80 cylinders, 21 sectors per track, 1.7 Mbyte capacity

high density

80 cylinders, 18 sectors per track, 1.44 Mbyte capacity

double density

80 cylinders, 9 sectors per track, 720 Kbyte capacity

extended density
80 cylinders, 36 sectors per track, 2.88 Mbyte capacity

1.7 Mbyte density

80 cylinders, 21 sectors per track, 1.7 Mbyte capacity

high density

80 cylinders, 18 sectors per track, 1.44 Mbyte capacity

double density

80 cylinders, 9 sectors per track, 760 Kbyte capacity

For 5.25" double-sided diskettes on x86 platforms, the densities listed below are supported:

5.25" diskettes are not supported on SPARC platforms.

high density
80 cylinders, 15 sectors per track, 1.2 Mbyte capacity

double density

40 cylinders, 9 sectors per track, 360 Kbyte capacity

double density

40 cylinders, 8 sectors per track, 320 Kbyte capacity

quad density

80 cylinders, 9 sectors per track, 720 Kbyte capacity

double density

40 cylinders, 16 sectors per track (256 bytes per sector), 320 Kbyte capacity

double density

40 cylinders, 4 sectors per track (1024 bytes per sector), 320 Kbyte capacity

EBUSY
During opening, the partition has been opened for exclusive access and another process wants to open the partition. Once open, this error is returned if the floppy disk driver attempted to pass a command to the floppy disk controller when the controller was busy handling another command. In this case, the application should try the operation again.

EFAULT

An invalid address was specified in an ioctl command (see fdio(7I)).

EINVAL

The number of bytes read or written is not a multiple of the diskette's sector size. This error is also returned when an unsupported command is specified using the FDIOCMD ioctl command (see fdio(7I)).

EIO

During opening, the diskette does not have a label or there is no diskette in the drive. Once open, this error is returned if the requested I/O transfer could not be completed.

ENOSPC

An attempt was made to write past the end of the diskette.

ENOTTY

The floppy disk driver does not support the requested ioctl functions (see fdio(7I)).

ENXIO

The floppy disk device does not exist or the device is not ready.

EROFS

The floppy disk device is opened for write access and the diskette in the drive is write protected.

ENOSYS
The floppy disk device does not support the requested ioctl function ( FDEJECT).

The driver attempts to initialize itself using the information found in the configuration file, /platform/i86pc/kernel/drv/fd.conf.


name="fd"  parent="fdc"  unit=0;
name="fd"  parent="fdc"  unit=1;

/platform/sun4u/kernel/drv/fd

driver module

/usr/include/sys/fdreg.h

structs and definitions for Intel 82072 and 82077 controllers

/usr/include/sys/fdvar.h

structs and definitions for floppy drivers

/dev/diskette

device file

/dev/diskette0

device file

/dev/rdiskette

raw device file

/dev/rdiskette0

raw device file

/dev/fd0[a-c]
block file

/dev/rfd0[a-c]

raw file

/dev/diskette0

directory containing volume management character device file

/dev/rdiskette0

directory containing the volume management raw character device file

/dev/aliases/floppy0

symbolic link to the entry in /dev/rdiskette0

/platform/i86pc/kernel/drv/fd

driver module

/platform/i86pc/kernel/drv/fd.conf

configuration file for floppy driver

/platform/i86pc/kernel/drv/fdc

floppy-controller driver module

/platform/i86pc/kernel/drv/fdc.conf

configuration file for the floppy-controller

/usr/include/sys/fdc.h

structs and definitions for x86 floppy devices

/usr/include/sys/fdmedia.h

structs and definitions for x86 floppy media

/dev/diskette
device file

/dev/diskette0

device file

/dev/rdiskette

raw device file

/dev/rdiskette0

raw device file

/dev/fd0[a-c]
block file

/dev/rfd0[a-c]

raw file

/dev/diskette0

directory containing volume management character device file

/dev/rdiskette0

directory containing the volume management raw character device file

/dev/aliases/floppy0

symbolic link to the entry in /dev/rdiskette0

/dev/diskette1
device file

/dev/rdiskette1

raw device file

/dev/fd1[a-c]
block file

/dev/rfd1[a-c]

raw file

/dev/diskette1

directory containing volume management character device file

/dev/rdiskette1

directory containing the volume management raw character device file

/dev/aliases/floppy1

symbolic link to the entry in /dev/rdiskette1

fdformat(1), dd(1M), drvconfig(1M), read(2), write(2), driver.conf(4), dkio(7I) fdio(7I)

fd<n>: <command name> failed (<sr1> <sr2> <sr3>)

The <command name> failed after several retries on drive <n>. The three hex values in parenthesis are the contents of status register 0, status register 1, and status register 2 of the Intel 8272, the Intel 82072, and the Intel 82077 Floppy Disk Controller on completion of the command, as documented in the data sheet for that part. This error message is usually followed by one of the following, interpreting the bits of the status register:

fd<n>:

not writable

fd<n>:

crc error blk <block number>

There was a data error on <block number>.

fd<n>:

bad format

fd<n>:

timeout

fd<n>:

drive not ready

fd<n>:

unformatted diskette or no diskette in drive

fd<n>:

block <block number> is past the end!

(nblk=<total number of blocks>)

The operation tried to access a block number that is greater than the total number of blocks.

fd<n>:

b_bcount 0x<op_size> not % 0x<sect_size>

The size of an operation is not a multiple of the sector size.

fd<n>:

overrun/underrun

fd<n>:

host bus error. There was a hardware error on a system bus.

Overrun/underrun errors occur when accessing a diskette while the system is heavily loaded. Decrease the load on the system and retry the diskette access.

3.5" high density diskettes have 18 sectors per track and 5.25" high density diskettes have 15 sectors per track. They can cross a track (though not a cylinder) boundary without losing data, so when using dd(1M) or read(2)/write(2) calls to or from the raw diskette, you should specify bs=18k or multiples thereof for 3.5" diskettes, and bs=15k or multiples thereof for 5.25" diskettes.

The SPARC fd driver is not an unloadable module.

Under Solaris (x86 Edition), the configuration of the floppy drives is specified in CMOS configuration memory. Use the BIOS setup program for the system to define the diskette size and density/capacity for each installed drive. Note that MS-DOS may operate the floppy drives correctly, even though the CMOS configuration may be in error. Solaris (x86 Edition) relies on the CMOS configuration to be accurate.

March 2, 2007 OmniOS