MOUNT(C) XENIX System V MOUNT(C)
Name
mount - Mounts a file structure.
Syntax
/etc/mount [ special-device directory [ -r ]]
/etc/umount special-device
/etc/mnt [ -rc ]
Description
mount announces to the system that a removable file
structure is present on special-device. The file structure
is mounted on directory. The directory must already exist;
it becomes the name of the root of the newly mounted file
structure. directory should be empty. If directory
contains files, they will appear to have been removed while
the directory is mounted and reappear when the directory is
unmounted.
The mount and umount commands maintain a table of mounted
devices. If each special device is invoked without any
arguments, mount displays the name of the device, and the
directory name of the mounted file structure, whether the
file structure is read-only, and the date it was mounted.
The optional last argument indicates that the file is to be
mounted read-only. Physically write-protected file
structures must be mounted in this way or errors occur when
access times are updated, whether or not any explicit write
is attempted.
umount removes the removable file structure previously
mounted on device special-device.
mnt is invoked from /etc/rc with the -rc flag to mount
filesystems when the system comes up multi-user. mnt uses
the file /etc/default/filesys for information on the
filesystems.
Files
/etc/mnttab Mount table
/etc/default/filesys
Filesystem data
See Also
umount(C), mount(S), mnttab(F), default(M)
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MOUNT(C) XENIX System V MOUNT(C)
Diagnostics
mount issues a warning if the file structure to be mounted
is currently mounted under another name.
Busy file structures cannot be dismounted with umount. A
file structure is busy if it contains an open file or some
user's working directory.
Notes
Some degree of validation is done on the file structure,
however it is generally unwise to mount corrupt file
structures.
Be warned that when in single-user mode, the commands that
look in /etc/mnttab for default arguments (for example df,
ncheck, quot, mount, and umount) give either incorrect
results (due to a corrupt /etc/mnttab from a non-shutdown
stoppage) or no results (due to an empty mnttab from a
shutdown stoppage).
When multi-user, this is not a problem; /etc/rc initializes
/etc/mnttab to contain only /dev/root and subsequent mounts
update it appropriately.
The mount(C) and umount(C) commands use a lock file to
guarantee exclusive access to /etc/mnttab. The commands
which just read it (those mentioned above) do not, so it is
possible that they may hit a window, which is corrupt. This
is not a problem in practice since mount and umount are not
frequent operations.
When mounting a file system on a floppy disk you need not
use the same directory each time. However, if you do, the
full pathnames for the files are consistent with each use.
Floppy disks must be unprotected (no write-protect tab) to
be mounted as a filesystem. Always unmount filesystems on
floppy disks before removing them from the floppy drive.
Failure to do so requires running fsck the next time the
disk is mounted .
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