mtools - utilities to access DOS disks in Unix.
Mtools is a collection of tools to allow Unix systems to manipulate MS-DOS files: read,
write, and move around files on an MS-DOS file system (typically a floppy disk). Where
reasonable, each program attempts to emulate the MS-DOS equivalent command. However,
unnecessary restrictions and oddities of DOS are not emulated. For instance, it is possi-
ble to move subdirectories from one subdirectory to another.
Mtools is sufficient to give access to MS-DOS file systems. For instance, commands such
as mdir a: work on the a: floppy without any preliminary mounting or initialization
(assuming the default `/etc/mtools.conf' works on your machine). With mtools, one can
change floppies too without unmounting and mounting.
Where to get mtools
Mtools can be found at the following places (and their mirrors):
Before reporting a bug, make sure that it has not yet been fixed in the Alpha patches
which can be found at:
These patches are named mtools-version-ddmm.taz, where version stands for the base ver-
sion, dd for the day and mm for the month. Due to a lack of space, I usually leave only
the most recent patch.
There is an mtools mailing list at mtools @ tux.org . Please send all bug reports to this
list. You may subscribe to the list by sending a message with 'subscribe mtools @
tux.org' in its body to majordomo @ tux.org . (N.B. Please remove the spaces around the
"@" both times. I left them there in order to fool spambots.) Announcements of new mtools
versions will also be sent to the list, in addition to the Linux announce newsgroups. The
mailing list is archived at http://lists.gnu.org/pipermail/info-mtools/
Common features of all mtools commands
Options and filenames
MS-DOS filenames are composed of a drive letter followed by a colon, a subdirectory, and a
filename. Only the filename part is mandatory, the drive letter and the subdirectory are
optional. Filenames without a drive letter refer to Unix files. Subdirectory names can use
either the '/' or '\' separator. The use of the '\' separator or wildcards requires the
names to be enclosed in quotes to protect them from the shell. However, wildcards in Unix
filenames should not be enclosed in quotes, because here we want the shell to expand them.
The regular expression "pattern matching" routines follow the Unix-style rules. For exam-
ple, `*' matches all MS-DOS files in lieu of `*.*'. The archive, hidden, read-only and
system attribute bits are ignored during pattern matching.
All options use the - (minus) as their first character, not / as you'd expect in MS-DOS.
Most mtools commands allow multiple filename parameters, which doesn't follow MS-DOS con-
ventions, but which is more user-friendly.
Most mtools commands allow options that instruct them how to handle file name clashes. See
section name clashes, for more details on these. All commands accept the -V flags which
prints the version, and most accept the -v flag, which switches on verbose mode. In ver-
bose mode, these commands print out the name of the MS-DOS files upon which they act,
unless stated otherwise. See section Commands, for a description of the options which are
specific to each command.
The meaning of the drive letters depends on the target architectures. However, on most
target architectures, drive A is the first floppy drive, drive B is the second floppy
drive (if available), drive J is a Jaz drive (if available), and drive Z is a Zip drive
(if available). On those systems where the device name is derived from the SCSI id, the
Jaz drive is assumed to be at SCSI target 4, and the Zip at SCSI target 5 (factory default
settings). On Linux, both drives are assumed to be the second drive on the SCSI bus
(/dev/sdb). The default settings can be changes using a configuration file (see section
The drive letter : (colon) has a special meaning. It is used to access image files which
are directly specified on the command line using the -i options.
mcopy -i my-image-file.bin ::file1 ::file2 .
This copies file1 and file2 from the image file (my-image-file.bin) to the /tmp directory.
You can also supply an offset within the image file by including @@offset into the file
mcopy -i my-image-file.bin@@1M ::file1 ::file2 .
This looks for the image at the offset of 1M in the file, rather than at its beginning.
Current working directory
The mcd command (`mcd') is used to establish the device and the current working directory
(relative to the MS-DOS file system), otherwise the default is assumed to be A:/. However,
unlike MS-DOS, there is only one working directory for all drives, and not one per drive.
VFAT-style long file names
This version of mtools supports VFAT style long filenames. If a Unix filename is too long
to fit in a short DOS name, it is stored as a VFAT long name, and a companion short name
is generated. This short name is what you see when you examine the disk with a pre-7.0
version of DOS.
The following table shows some examples of short names:
Long name MS-DOS name Reason for the change
--------- ---------- ---------------------
thisisatest THISIS~1 filename too long
alain.knaff ALAIN~1.KNA extension too long
prn.txt PRN~1.TXT PRN is a device name
.abc ABC~1 null filename
hot+cold HOT_CO~1 illegal character
As you see, the following transformations happen to derive a short name:
* Illegal characters are replaced by underscores. The illegal characters are
* Extra dots, which cannot be interpreted as a main name/extension separator are
* A ~n number is generated,
* The name is shortened so as to fit in the 8+3 limitation
The initial Unix-style file name (whether long or short) is also called the primary name,
and the derived short name is also called the secondary name.
mcopy /etc/motd a:Reallylongname
Mtools creates a VFAT entry for Reallylongname, and uses REALLYLO as a short name. Real-
lylongname is the primary name, and REALLYLO is the secondary name.
mcopy /etc/motd a:motd
Motd fits into the DOS filename limits. Mtools doesn't need to derivate another name.
Motd is the primary name, and there is no secondary name.
In a nutshell: The primary name is the long name, if one exists, or the short name if
there is no long name.
Although VFAT is much more flexible than FAT, there are still names that are not accept-
able, even in VFAT. There are still some illegal characters left (\"*\\<>/?:|), and device
names are still reserved.
Unix name Long name Reason for the change
--------- ---------- ---------------------
prn prn-1 PRN is a device name
ab:c ab_c-1 illegal character
As you see, the following transformations happen if a long name is illegal:
* Illegal characters are replaces by underscores,
* A -n number is generated,
When writing a file to disk, its long name or short name may collide with an already
existing file or directory. This may happen for all commands which create new directory
entries, such as mcopy, mmd, mren, mmove. When a name clash happens, mtools asks you what
it should do. It offers several choices:
Overwrites the existing file. It is not possible to overwrite a directory with a
Renames the newly created file. Mtools prompts for the new filename
Renames the newly created file. Mtools chooses a name by itself, without prompting
skip Gives up on this file, and moves on to the next (if any)
To chose one of these actions, type its first letter at the prompt. If you use a lower
case letter, the action only applies for this file only, if you use an upper case letter,
the action applies to all files, and you won't be prompted again.
You may also chose actions (for all files) on the command line, when invoking mtools:
-D o Overwrites primary names by default.
-D O Overwrites secondary names by default.
-D r Renames primary name by default.
-D R Renames secondary name by default.
-D a Autorenames primary name by default.
-D A Autorenames secondary name by default.
-D s Skip primary name by default.
-D S Skip secondary name by default.
-D m Ask user what to do with primary name.
-D M Ask user what to do with secondary name.
Note that for command line switches lower/upper differentiates between primary/secondary
name whereas for interactive choices, lower/upper differentiates between just-this-
The primary name is the name as displayed in Windows 95 or Windows NT: i.e. the long name
if it exists, and the short name otherwise. The secondary name is the "hidden" name, i.e.
the short name if a long name exists.
By default, the user is prompted if the primary name clashes, and the secondary name is
If a name clash occurs in a Unix directory, mtools only asks whether to overwrite the
file, or to skip it.
Case sensitivity of the VFAT file system
The VFAT file system is able to remember the case of the filenames. However, filenames
which differ only in case are not allowed to coexist in the same directory. For example if
you store a file called LongFileName on a VFAT file system, mdir shows this file as Long-
FileName, and not as Longfilename. However, if you then try to add LongFilename to the
same directory, it is refused, because case is ignored for clash checks.
The VFAT file system allows to store the case of a filename in the attribute byte, if all
letters of the filename are the same case, and if all letters of the extension are the
same case too. Mtools uses this information when displaying the files, and also to gener-
ate the Unix filename when mcopying to a Unix directory. This may have unexpected results
when applied to files written using an pre-7.0 version of DOS: Indeed, the old style file-
names map to all upper case. This is different from the behavior of the old version of
mtools which used to generate lower case Unix filenames.
high capacity formats
Mtools supports a number of formats which allow to store more data on disk as usual. Due
to different operating system abilities, these formats are not supported on all operating
systems. Mtools recognizes these formats transparently where supported.
In order to format these disks, you need to use an operating system specific tool. For
Linux, suitable floppy tools can be found in the fdutils package at the following loca-
See the manual pages included in that package for further detail: Use superformat to for-
mat all formats except XDF, and use xdfcopy to format XDF.
The oldest method of fitting more data on a disk is to use more sectors and more cylin-
ders. Although the standard format uses 80 cylinders and 18 sectors (on a 3 1/2 high den-
sity disk), it is possible to use up to 83 cylinders (on most drives) and up to 21 sec-
tors. This method allows to store up to 1743K on a 3 1/2 HD disk. However, 21 sector disks
are twice as slow as the standard 18 sector disks because the sectors are packed so close
together that we need to interleave them. This problem doesn't exist for 20 sector for-
These formats are supported by numerous DOS shareware utilities such as fdformat and vga-
copy. In his infinite hubris, Bill Gate$ believed that he invented this, and called it
`DMF disks', or `Windows formatted disks'. But in reality, it has already existed years
before! Mtools supports these formats on Linux, on SunOS and on the DELL Unix PC.
By using bigger sectors it is possible to go beyond the capacity which can be obtained by
the standard 512-byte sectors. This is because of the sector header. The sector header has
the same size, regardless of how many data bytes are in the sector. Thus, we save some
space by using fewer, but bigger sectors. For example, 1 sector of 4K only takes up header
space once, whereas 8 sectors of 512 bytes have also 8 headers, for the same amount of
This method allows to store up to 1992K on a 3 1/2 HD disk.
Mtools supports these formats only on Linux.
The 2m format was originally invented by Ciriaco Garcia de Celis. It also uses bigger sec-
tors than usual in order to fit more data on the disk. However, it uses the standard for-
mat (18 sectors of 512 bytes each) on the first cylinder, in order to make these disks
easier to handle by DOS. Indeed this method allows to have a standard sized boot sector,
which contains a description of how the rest of the disk should be read.
However, the drawback of this is that the first cylinder can hold less data than the oth-
ers. Unfortunately, DOS can only handle disks where each track contains the same amount of
data. Thus 2m hides the fact that the first track contains less data by using a shadow
FAT. (Usually, DOS stores the FAT in two identical copies, for additional safety. XDF
stores only one copy, but tells DOS that it stores two. Thus the space that would be taken
up by the second FAT copy is saved.) This also means that you should never use a 2m disk
to store anything else than a DOS file system.
Mtools supports these formats only on Linux.
XDF is a high capacity format used by OS/2. It can hold 1840 K per disk. That's lower than
the best 2m formats, but its main advantage is that it is fast: 600 milliseconds per
track. That's faster than the 21 sector format, and almost as fast as the standard 18 sec-
tor format. In order to access these disks, make sure mtools has been compiled with XDF
support, and set the use_xdf variable for the drive in the configuration file. See section
Compiling mtools, and `miscellaneous variables', for details on how to do this. Fast XDF
access is only available for Linux kernels which are more recent than 1.1.34.
Mtools supports this format only on Linux.
Caution / Attention distributors: If mtools is compiled on a Linux kernel more recent than
1.3.34, it won't run on an older kernel. However, if it has been compiled on an older ker-
nel, it still runs on a newer kernel, except that XDF access is slower. It is recommended
that distribution authors only include mtools binaries compiled on kernels older than
1.3.34 until 2.0 comes out. When 2.0 will be out, mtools binaries compiled on newer ker-
nels may (and should) be distributed. Mtools binaries compiled on kernels older than
1.3.34 won't run on any 2.1 kernel or later.
All the Mtools commands return 0 on success, 1 on utter failure, or 2 on partial failure.
All the Mtools commands perform a few sanity checks before going ahead, to make sure that
the disk is indeed an MS-DOS disk (as opposed to, say an ext2 or MINIX disk). These checks
may reject partially corrupted disks, which might otherwise still be readable. To avoid
these checks, set the MTOOLS_SKIP_CHECK environmental variable or the corresponding con-
figuration file variable (see section global variables)
An unfortunate side effect of not guessing the proper device (when multiple disk capaci-
ties are supported) is an occasional error message from the device driver. These can be
The fat checking code chokes on 1.72 Mb disks mformatted with pre-2.0.7 mtools. Set the
environmental variable MTOOLS_FAT_COMPATIBILITY (or the corresponding configuration file
variable, `global variables') to bypass the fat checking.
floppyd_installtest mattrib mbadblocks mcd mclasserase mcopy mdel mdeltree mdir mdu mfor-
mat minfo mkmanifest mlabel mmd mmount mmove mrd mren mshortname mshowfat mtoolstest mtype
mtools-4.0.18 09Jan13 mtools(1)