mtools.conf - mtools configuration files
This manpage describes the configuration files for mtools. They are
called ‘/etc/mtools.conf’ and ‘~/.mtoolsrc’. If the environmental
variable MTOOLSRC is set, its contents is used as the filename for a
third configuration file. These configuration files describe the
* Global configuration flags and variables
* Per drive flags and variables
Location of the configuration files
‘/etc/mtools.conf’ is the system-wide configuration file, and
‘~/.mtoolsrc’ is the user’s private configuration file.
On some systems, the system-wide configuration file is called
General configuration file syntax
The configuration files is made up of sections. Each section starts
with a keyword identifying the section followed by a colon. Then
follow variable assignments and flags. Variable assignments take the
Flags are lone keywords without an equal sign and value following them.
A section either ends at the end of the file or where the next section
Lines starting with a hash (#) are comments. Newline characters are
equivalent to whitespace (except where ending a comment). The
configuration file is case insensitive, except for item enclosed in
quotes (such as filenames).
For most platforms, mtools contains reasonable compiled-in defaults for
physical floppy drives. Thus, you usually don’t need to bother with
the configuration file, if all you want to do with mtools is to access
your floppy drives. On the other hand, the configuration file is needed
if you also want to use mtools to access your hard disk partitions and
dosemu image files.
Global flags may be set to 1 or to 0.
The following global flags are recognized:
If this is set to 1, mtools skips most of its sanity checks.
This is needed to read some Atari disks which have been made
with the earlier ROMs, and which would not be recognized
If this is set to 1, mtools skips the fat size checks. Some
disks have a bigger FAT than they really need to. These are
rejected if this option is not set.
If this is set to 1, mtools displays all-upper-case short
filenames as lowercase. This has been done to allow a behavior
which is consistent with older versions of mtools which didn’t
know about the case bits.
If this is set to 1, mtools won’t generate VFAT entries for
filenames which are mixed-case, but otherwise legal dos
filenames. This is useful when working with DOS versions which
can’t grok VFAT longnames, such as FreeDos.
In a wide directory, prints the short name with a dot instead of
spaces separating the basename and the extension.
If this is set to one (default), generate numeric tails for all
long names (~1). If set to zero, only generate numeric tails if
otherwise a clash would have happened.
If 1, uses the European notation for times (twenty four hour
clock), else uses the UK/US notation (am/pm)
Example: Inserting the following line into your configuration file
instructs mtools to skip the sanity checks:
Global variables may also be set via the environment:
Global string variables may be set to any value:
The format used for printing dates of files. By default, is dd-
Per drive flags and variables
Per drive flags and values may be described in a drive section. A drive
section starts with drive "driveletter" :
Then follow variable-value pairs and flags.
This is a sample drive description:
For each drive, you need to describe where its data is physically
stored (imag file, physical device, partition, offset).
file The name of the file or device holding the disk image. This is
mandatory. The file name should be enclosed in quotes.
Tells mtools to treat the drive as a partitioned device, and to
use the given partition. Only primary partitions are accessible
using this method, and they are numbered from 1 to 4. For
logical partitions, use the more general offset variable. The
partition variable is intended for removable media such as
Syquests, ZIP drives, and magneto-optical disks. Although
traditional DOS sees Syquests and magneto-optical disks as
‘giant floppy disks’ which are unpartitioned, OS/2 and Windows
NT treat them like hard disks, i.e. partioned devices. The
partition flag is also useful DOSEMU hdimages. It is not
recommended for hard disks for which direct access to partitions
is available through mounting.
Describes where in the file the MS-DOS filesystem starts. This
is useful for logical partitions in DOSEMU hdimages, and for
ATARI ram disks. By default, this is zero, meaning that the
filesystem starts right at the beginning of the device or file.
Disk Geometry Configuration
Geometry information describes the physical characteristics about the
disk. Its has three purposes:
The geometry information is written into the boot sector of the
newly made disk. However, you may also describe the geometry
information on the command line. See section mformat, for
On some Unices there are device nodes which only support one
physical geometry. For instance, you might need a different node
to access a disk as high density or as low density. The geometry
is compared to the actual geometry stored on the boot sector to
make sure that this device node is able to correctly read the
disk. If the geometry doesn’t match, this drive entry fails, and
the next drive entry bearing the same drive letter is tried. See
section multiple descriptions, for more details on supplying
several descriptions for one drive letter.
If no geometry information is supplied in the configuration
file, all disks are accepted. On Linux (and on Sparc) there
exist device nodes with configurable geometry (‘/dev/fd0’,
‘/dev/fd1’ etc), and thus filtering is not needed (and ignored)
for disk drives. (Mtools still does do filtering on plain files
(disk images) in Linux: this is mainly intended for test
purposes, as I don’t have access to a Unix which would actually
If you do not need filtering, but want still a default geometry
for mformatting, you may switch off filtering using the
If you want filtering, you should supply the filter flag. If
you supply a geometry, you must supply one of both flags.
On devices that support it (usually floppy devices), the
geometry information is also used to set the initial geometry.
This initial geometry is applied while reading the boot sector,
which contains the real geometry. If no geometry information is
supplied in the configuration file, or if the mformat_only flag
is supplied, no initial configuration is done.
On Linux, initial geometry is not really needed, as the
configurable devices are able to auto-detect the disk type
accurately enough (for most common formats) to read the boot
Wrong geometry information may lead to very bizarre errors. That’s why
I strongly recommend that you add the mformat_only flag to your drive
description, unless you really need filtering or initial geometry.
The following geometry related variables are available:
tracks The number of cylinders. (cylinders is the preferred form,
tracks is considered obsolete)
heads The number of heads (sides).
The number of sectors per track.
Example: the following drive section describes a 1.44M drive:
cylinders=80 heads=2 sectors=18
The following shorthand geometry descriptions are available:
1.44m high density 3 1/2 disk. Equivalent to: fat_bits=12 cylinders=80
1.2m high density 5 1/4 disk. Equivalent to: fat_bits=12 cylinders=80
720k double density 3 1/2 disk. Equivalent to: fat_bits=12
cylinders=80 heads=2 sectors=9
360k double density 5 1/4 disk. Equivalent to: fat_bits=12
cylinders=40 heads=2 sectors=9
The shorthand format descriptions may be amended. For example, 360k
sectors=8 describes a 320k disk and is equivalent to: fat_bits=12
cylinders=40 heads=2 sectors=8
Moreover, the following flags are available:
sync All i/o operations are done synchronously
The device or file is opened with the O_NDELAY flag. This is
needed on some non-Linux architectures.
The device or file is opened with the O_EXCL flag. On Linux,
this ensures exclusive access to the floppy drive. On most other
architectures, and for plain files it has no effect at all.
General Purpose Drive Variables
The following general purpose drive variables are available. Depending
to their type, these variables can be set to a string (precmd) or an
integer (all others)
The number of FAT bits. This may be 12 or 16. This is very
rarely needed, as it can almost always be deduced from
information in the boot sector. On the contrary, describing the
number of fat bits may actually be harmful if you get it wrong.
You should only use it if mtools gets the autodetected number of
fat bits wrong, or if you want to mformat a disk with a weird
number of fat bits.
Describes the DOS codepage used for short filenames. This is a
number between 1 and 999. By default, codepage 850 is used. The
reason for this is because this codepage contains most of the
characters that are also available in ISO-Latin-1. You may also
specify a global codepage for all drives by using the global
default_codepage parameter (outside of any drive description).
This parameters exists starting at version 4.0.0
On some variants of Solaris, it is necessary to call ’volcheck
-v’ before opening a floppy device, in order for the system to
notice that there is indeed a disk in the drive.
precmd="volcheck -v" in the drive clause establishes the desired
This parameter represents a default block size to be always used
on this device. All I/O is done with multiples of this block
size, independantly of the sector size registered in the
filesystem’s boot sector. This is useful for character devices
whose sector size is not 512, such as for example CD Rom drives
Only the file variable is mandatory. The other parameters may be left
out. In that case a default value or an autodetected value is used.
General Purpose Drive Flags
A flag can either be set to 1 (enabled) or 0 (disabled). If the value
is ommitted, it is enabled. For example, scsi is equivalent to scsi=1
Instruct mtools to not use locking on this drive. This is
needed on systems with buggy locking semantics. However,
enabling this makes operation less safe in cases where several
users may access the same drive at the same time.
scsi When set to 1, this option tells mtools to use raw SCSI I/O
instead of the standard read/write calls to access the device.
Currently, this is supported on HP/UX, Solaris and SunOs. This
is needed because on some architectures, such as SunOs or
Solaris, PC media can’t be accessed using the read and write
syscalls, because the OS expects them to contain a Sun specific
As raw Scsi access always uses the whole device, you need to
specify the "partition" flag in addition
On some architectures, such as Solaris, mtools needs root
privileges to be able to use the scsi option. Thus mtools
should be installed set uid root on Solaris if you want to
access Zip/Jaz drives. Thus, if the scsi flag is given,
privileged is automatically implied, unless explicitly disabled
Mtools uses its root privileges to open the device, and to issue
the actual SCSI I/O calls. Moreover, root privileges are only
used for drives described in a system-wide configuration file
such as ‘/etc/mtools.conf’, and not for those described in
‘~/.mtoolsrc’ or ‘$MTOOLSRC’.
When set to 1, this instructs mtools to use its set-uid and set-
gid privileges for opening the given drive. This option is only
valid for drives described in the system-wide configuration
files (such as ‘/etc/mtools.conf’, not ‘~/.mtoolsrc’ or
‘$MTOOLSRC’). Obviously, this option is also a no op if mtools
is not installed setuid or setgid. This option is implied by
’scsi=1’, but again only for drives defined in system-wide
configuration files. Privileged may also be set explicitely to
0, in order to tell mtools not to use its privileges for a given
drive even if scsi=1 is set.
Mtools only needs to be installed setuid if you use the
privileged or scsi drive variables. If you do not use these
options, mtools works perfectly well even when not installed
Instructs mtools to interpret the device name as a vold
identifier rather than as a filename. The vold identifier is
translated into a real filename using the media_findname() and
media_oldaliases() functions of the volmgt library. This flag
is only available if you configured mtools with the --enable-
new-vold option before compilation.
Consider the media as a word-swapped Atari disk.
If this is set to a non-zero value, mtools also tries to access
this disk as an XDF disk. XDF is a high capacity format used by
OS/2. This is off by default. See section XDF, for more details.
Tells mtools to use the geometry for this drive only for
mformatting and not for filtering.
Tells mtools to use the geometry for this drive both for
mformatting and filtering.
Tells mtools to connect to floppyd (see section floppyd).
Supplying multiple descriptions for a drive
It is possible to supply multiple descriptions for a drive. In that
case, the descriptions are tried in order until one is found that fits.
Descriptions may fail for several reasons:
1. because the geometry is not appropriate,
2. because there is no disk in the drive,
3. or because of other problems.
Multiple definitions are useful when using physical devices which are
only able to support one single disk geometry. Example:
drive a: file="/dev/fd0H1440" 1.44m
drive a: file="/dev/fd0H720" 720k
This instructs mtools to use /dev/fd0H1440 for 1.44m (high density)
disks and /dev/fd0H720 for 720k (double density) disks. On Linux, this
feature is not really needed, as the /dev/fd0 device is able to handle
You may also use multiple drive descriptions to access both of your
physical drives through one drive letter:
drive z: file="/dev/fd0"
drive z: file="/dev/fd1"
With this description, mdir z: accesses your first physical drive if it
contains a disk. If the first drive doesn’t contain a disk, mtools
checks the second drive.
When using multiple configuration files, drive descriptions in the
files parsed last override descriptions for the same drive in earlier
files. In order to avoid this, use the drive+ or +drive keywords
instead of drive. The first adds a description to the end of the list
(i.e. it will be tried last), and the first adds it to the start of the
Location of configuration files and parsing order
The configuration files are parsed in the following order:
1. compiled-in defaults
3. ‘/etc/mtools’ This is for backwards compatibility only, and is
only parsed if ‘mtools.conf’ doesn’t exist.
5. ‘$MTOOLSRC’ (file pointed by the MTOOLSRC environmental
Options described in the later files override those described in the
earlier files. Drives defined in earlier files persist if they are not
overridden in the later files. For instance, drives A and B may be
defined in ‘/etc/mtools.conf’ and drives C and D may be defined in
‘~/.mtoolsrc’ However, if ‘~/.mtoolsrc’ also defines drive A, this new
description would override the description of drive A in
‘/etc/mtools.conf’ instead of adding to it. If you want to add a new
description to a drive already described in an earlier file, you need
to use either the +drive or drive+ keyword.
Backwards compatibility with old configuration file syntax
The syntax described herein is new for version mtools-3.0. The old
line-oriented syntax is still supported. Each line beginning with a
single letter is considered to be a drive description using the old
syntax. Old style and new style drive sections may be mixed within the
same configuration file, in order to make upgrading easier. Support for
the old syntax will be phased out eventually, and in order to
discourage its use, I purposefully omit its description here.