freebsd-dev/sbin/mount_msdos/mount_msdos.8

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.\"
.\" Copyright (c) 1993,1994 Christopher G. Demetriou
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.\" This product includes software developed by Christopher G. Demetriou.
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.\" $Id: mount_msdos.8,v 1.5 1997/02/22 14:32:29 peter Exp $
.\"
.Dd April 7, 1994
.Dt MOUNT_MSDOS 8
.Os FreeBSD 2.0
.Sh NAME
.Nm mount_msdos
.Nd mount an MS-DOS file system
.Sh SYNOPSIS
.Nm mount_msdos
.Op Fl u Ar uid
.Op Fl g Ar gid
.Op Fl m Ar mask
.Pa special
.Pa node
.Sh DESCRIPTION
The
.Nm mount_msdos
command attaches the MS-DOS filesystem residing on
the device
.Pa special
to the global filesystem namespace at the location
indicated by
.Pa node .
This command is normally executed by
.Xr mount 8
at boot time, but can be used by any user to mount an
MS-DOS file system on any directory that they own (provided,
of course, that they have appropriate access to the device that
contains the file system).
.Pp
The options are as follows:
.Bl -tag -width Ds
.It Fl u
Set the owner of the files in the file system to
.Ar uid .
The default owner is the owner of the directory
on which the file system is being mounted.
.It Fl g
Set the group of the files in the file system to
.Ar gid .
The default group is the group of the directory
on which the file system is being mounted.
.It Fl m
Specify the maximum file permissions for files
in the file system.
(For example, a mask of
.Li 755
specifies that, by default, the owner should have
read, write, and execute permissions for files, but
others should only have read and execute permissions.
See
.Xr chmod 1
for more information about octal file modes.)
Only the nine low-order bits of
.Ar mask
are used.
The default mask is taken from the
directory on which the file system is being mounted.
.El
.Sh SEE ALSO
.Xr mount 2 ,
.Xr unmount 2 ,
.Xr fstab 5
.Sh CAVEATS
The
.Nm msdos
filesystem is not known to work reliably with filesystems created by versions
of MS-DOS later than version 6.22.
.Pp
The limitations on file names imposed by MS-DOS are strange, at best.
For instance, they are
limited to single-case, 8 character names with 3 character extensions.
.Pp
.Fx 2.1
and earlier versions could not handle cluster sizes larger than 16K.
Just mounting an MS-DOS file system could cause corruption to any
mounted file system.
Cluster sizes larger than 16K are unavoidable for file system sizes
larger than 1G, and also occur when filesystems larger than 1G are
shrunk to smaller than 1G using FIPS.
The warning:
.Pp
mountmsdosfs(): Warning: root directory is not a multiple of the clustersize in length
.Pp
is common when the cluster size is large and/or the filesystem has been
shrunk, but it is not directly related to any known problems.
.Sh HISTORY
The
.Nm mount_msdos
utility first appeared in
.Fx 2.0 .
Its predecessor, the
.Nm mount_pcfs
utility appeared in
.Fx 1.0 ,
and was abandoned in favor
of the more aptly-named
.Nm mount_msdos .