fdmount(1) General Commands Manual fdmount(1)
fdmount - Floppy disk mount utility
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fdmount [-l] [--list] [-d] [--daemon] [--detach]
[-i interval] [--interval interval] [-o mount-options]
[-r] [-readonly] [-s] [--sync] [--nosync] [--nodev]
[--nosuid] [--noexec] [-f] [--force] [-h] [--help]
fdumount [-f] [--force] [drivename]
fdmountd [-i interval] [--interval interval] [-r]
[-readonly] [-s] [--sync] [--nosync] [--nodev]
[--nosuid] [--noexec] [--help] [drivename] [mountpoint]]
The fdmount program mounts a floppy disk in the specified drive. It
tries to figure out the exact format and filesystem type of the disk
from data in the disk's boot sector or super block and the auto-
detected track layout.
Currently, fdmount supports the filesystems minix, ext, ext2, xia, and
msdos, and includes special support for disks formatted by the 2M util-
ity for MS-DOS.
It also checks whether the disk is write protected, in which case it is
The symbolic drivename is (currently) one of `fd[0-7]', corresponding
to the special device files `/dev/fd[0-7]'. If drivename is not speci-
fied, `fd0' is assumed.
The disk is mounted on the directory mountpoint, if specified, or on
`/fd[0-7]'. In either case, the mount point must be an existing,
Due to a bug in the floppy driver (?), the polling interval (-i flag)
must be longer than the spindown offset. Thus you need to do (for exam-
ple) floppycontrol --spindown 99 before starting fdmountd in daemon
List all known drives with their symbolic name, type, and mount
Run in daemon mode (see below).
Runs daemon in background, and detaches it from its tty. Mes-
sages produced after the fork are logged to syslog.
Dumps the process id of the daemon to file. This makes killing
the daemon easier: kill -9 `cat file`
Set the polling interval for daemon mode. The unit for interval
is 0.1 seconds, the default value is 10 (i.e. 1 second).
Sets filesystem-specific options. So far, these are only avail-
able for DOS and Ext2 disks. The following DOS options are sup-
ported: check, conv, dotsOK, debug, fat, quiet, blocksize. The
following Ext2 options are supported: check, errors, grpid, bsd-
groups, nogrpid, sysvgroups, bsddf, minixdf, resgid, debug,
nocheck. When running as a daemon, options not applying to the
disk that is inserted (because of its filesystem type) are not
passed to mount.
Mount the disk read-only. This is automatically assumed if the
disk is write protected.
Mount with the SYNC option.
Mounts without the SYNC option, even when running as daemon.
Mount with the NODEV option. Ignored for msdos filesystems, oth-
erwise always set for non-root users.
Mount with the NOSUID option. Ignored for msdos filesystems,
otherwise always set for non-root users.
Mount with the NOEXEC option.
Attempt a mount or unmount operation even `/etc/mtab' says that
the drive is already mounted, or not mounted, respectively.
This option is useful if `/etc/mtab' got out of sync with the
actual state for some reason.
Show short parameter description
When mounting on the default mount point, the mount points' owner is
set to the current user, and the access flags according to the user's
umask. For a specified mountpoint, owner and permissions are left
unchanged. Default mount points are called /fd0, /fd1, ... , /fd7.
The user running fdmount must have read access to the floppy device for
read only mounts, and read/write access for read/write mounts.
Fdmount can be run suid root, allowing users to mount floppy disks. The
following restrictions are placed upon non-root users:
* If a mountpoint is specified explicitly, it must be owned by the
* A user may only unmount a disk if the mount point is owned by
the user, or if it the disk has been mounted by the same user.
* Non-msdos disks are automatically mounted with the nodev and
nosuid flags set.
However, do not rely on fdmount being secure at the moment.
In daemon mode, the specified drive is periodically checked and if a
disk is inserted, it is automatically mounted.
When the disk is removed, it is automatically unmounted. However, it
is recommended to unmount the disk manually before removing it. In
order to limit corruption, disks are mounted with the SYNC option when
running in daemon mode, unless the --nosync flag is given.
Note that this mode has some potential drawbacks:
* Some floppy drives have to move the drive head physically in
order to reset the disk change signal. It is strongly recom-
mended not to use daemon mode with these drives. See section
floppycontrol, for details.
* If a disk does not contain a filesystem (e.g. a tar archive),
the mount attempt may slow down initial access.
* As fdmount cannot identify the user trying to use the disk
drive, there is no way to protect privacy. Disks are always
mounted with public access permissions set.
error opening device name
error reading boot/super block
fdmount failed to read the first 1K of the disk. The disk might
be damaged, unformatted, or it may have a format which is unsup-
ported by the FDC or the Linux kernel.
unknown filesystem type
No magic number of any of the supported filesystems (see above)
could be identified.
sorry, can't figure out format (fs filesystem)
The size of the filesystem on the disk is incompatible with the
track layout detected by the kernel and an integer number of
tracks. This may occur if the filesystem uses only part of the
disk, or the track layout was detected incorrectly by the ker-
failed to mount fs> <sizeK-disk
The actual mount system call failed.
failed to unmount
The actual unmount system call failed.
cannot create lock file /etc/mtab~
If `/etc/mtab~' exists, you should probably delete it. Other-
wise, check permissions.
Can't access mountpoint
Most probably, the default or specified mount point does not
exist. Use mkdir.
mountpoint is not a directory
The mountpoint is not a directory.
not owner of mountpoint
Non-root users must own the directory specified as mount point.
(This does not apply for the default mount points, /fd[0-3].)
No write permission to mountpoint
Non-root users must have write permission on the mount point
Not owner of mounted directory: UID=uid
Non-root users cannot unmount if the mount point is owned (i.e.
the disk was mounted) by another user.
invalid drive name
Valid drive names are `fd0', `fd1', etc.
drive name does not exist
The drive does not exist physically, is unknown to the Linux
kernel, or is an unknown type.
Drive name is mounted already
Trying to mount a drive which appears to be mounted already.
Use the --force option if you think this is wrong.
Drive name is not mounted
Trying to unmount a drive which does not appear to be mounted.
Use the --force option if you think this is wrong.
If this occurs with the FDGETDRVTYP or FDGETDRVSTAT, ioctl's you
should probably update your Linux kernel.
mounted fs size-disk (options)
* Fdmount should be more flexible about drive names and default
mount points (currently hard coded).
* Probably not very secure yet (when running suid root). Untested
with ext and xia filesystems.
* Can't specify filesystem type and disk layout explicitly.
* In daemon mode, the drive light stays on all the time.
* Some newer filesystem types, such as vfat are not yet supported.
Fdutils' texinfo doc
fdutils-5.5 03Mar05 fdmount(1)
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