mkudffs(8) — Linux manual page


MKUDFFS(8)                 System Manager's Manual                MKUDFFS(8)

NAME         top

       mkudffs — create a UDF filesystem

SYNOPSIS         top

       mkudffs [ options ] device [ blocks-count ]

DESCRIPTION         top

       mkudffs is used to create a UDF filesystem on a device (usually a
       disk). device is the special file corresponding to the device (e.g.
       /dev/hdX) or file image. blocks-count is the number of blocks on the
       device. If omitted, mkudffs automagically figures the filesystem
       size. The order of options matters. Encoding option must be first and
       options to override default settings implied by the media type or UDF
       revision should be after the option they are overriding.

OPTIONS         top

              Display the usage and list of options.

       -l,--label= label
              Specify the UDF label. UDF label is synonym for specifying
              both --lvid and --vid options. If omitted, mkudffs label is
              LinuxUDF. (Option available since mkudffs 1.1)

       -u,--uuid= uuid
              Specify the UDF uuid. It must be exactly 16 hexadecimal
              lowercase digits and is used for first 16 characters of
              --fullvsid option. If omitted, mkudffs uuid is generated from
              local time and a random number. (Option available since
              mkudffs 1.1)

       -b,--blocksize= block-size
              Specify the size of blocks in bytes. Valid block size for a
              UDF filesystem is power of two in range from 512 to 32768 and
              must match a device logical (sector) size. If omitted, mkudffs
              block size is set to device logical block (sector) size. If
              logical block (sector) size is unknown (e.g. when creating
              disk image) then for --media-type=hd is used block size 512
              and for other media types 2048. (Prior to mkudffs 1.1 default
              value was always 2048 independently of --media-type)

       -m,--media-type= media-type
              Specify the media type. Must be specified before --udfrev.
              Default value is autodetected. When autodetection does not
              work (e.g. when creating disk image) then hd value is assumed.
              Valid media types are:

                   hd              HD (Hard Disk)

                   worm            WORM (Write Once Read Many)

                   mo              MO (Magneto Optical)

                   cd              CD-ROM (CD Read-Only Memory)

                   cdr             CD-R (CD Recordable)

                   cdrw            CD-RW (CD Read-Write)

                   dvd             DVD-ROM (DVD Read-Only Memory)

                   dvdr            DVD-R (DVD Recordable)

                   dvdrw           DVD-RW (DVD Read-Write)

                   dvdram          DVD-RAM (DVD Random Access Memory)

                   bdr             BD-R (Blu-ray Disc Recordable)

              (Short option variant -m and values cd, dvdr, bdr are
              available since mkudffs 2.0 and autodetection is supported
              since mkudffs 2.2)

       -r,--udfrev= udf-revision
              Specify the UDF revision to use, either in hexadecimal BCD
              (e.g. 0x0201) or decimal (e.g. 2.01) format. Valid revisions
              are 1.01, 1.02, 1.50, 2.00, 2.01, 2.50 and 2.60. If omitted,
              mkudffs UDF revision is 2.01, except for Blu-ray Discs which
              is 2.50. UDF revisions higher then 2.01 are experimental.
              Option must be specified after --media-type. (Values in
              decimal format and UDF revisions higher then 2.01 are
              supported since mkudffs 2.0, UDF revision 1.01 is supported
              since mkudffs 2.1)

              Not really, do not write to device. Just simulate and display
              what would happen with device. Useful for determining the
              calculated location of different UDF blocks. (Option available
              since mkudffs 2.0)

              Create a new image file specified by device with blocks-count
              and fail if file already exists. If omitted, mkudffs creates a
              new image file only in case it does not exist yet. (Option
              available since mkudffs 2.0)

       --lvid= logical-volume-identifier
              Specify the Logical Volume Identifier. If omitted, mkudffs
              Logical Volume Identifier is LinuxUDF. Most UDF
              implementations use this identifier as a disk label.

       --vid= volume-identifier
              Specify the Volume Identifier. If omitted, mkudffs Volume
              Identifier is LinuxUDF.

       --vsid= volume-set-identifier
              Specify the 17.–127. character of Volume Set Identifier. If
              omitted, mkudffs Volume Set Identifier is LinuxUDF.

       --fsid= file-set-identifier
              Specify the File Set Identifier. If omitted, mkudffs File Set
              Identifier is LinuxUDF.

       --fullvsid= full-volume-set-identifier
              Specify the full Volume Set Identifier. Overwrite previous
              --uuid and --vsid options. (Option available since mkudffs

       --uid= uid
              Specify the uid of the root (/) directory. If omitted, mkudffs
              uid is 0. Special value -1 means invalid or not specified uid.
              (Option available since mkudffs 1.1)

       --gid= gid
              Specify the gid of the root (/) directory. If omitted, mkudffs
              gid is 0. Special value -1 means invalid or not specified gid.
              (Option available since mkudffs 1.1)

       --mode= mode
              Specify permissions in octal mode bits of the root (/)
              directory. If omitted, mkudffs mode is 0755. (Option available
              since mkudffs 2.0)

              This option specify that the whole UDF disk should be treated
              as read-only. It sets SoftWriteProtect domain flag in Logical
              Volume Descriptor and in File Set Descriptor. Plus for
              overwritable media types (hd, dvdram, dvdrw) set UDF Access
              Type to read-only. (Option available since mkudffs 2.2)

       --bootarea= fill
              Specify how to fill UDF boot area which is the first 32kB of
              the disk and is not used by UDF itself. Option mbr make sense
              only when running mkudffs on whole disk, not on just one
              partition. Valid options are:

                   preserve      preserve existing UDF boot area, do not
                                 touch it (default for media type different
                                 from hd)

                   erase         erase existing UDF boot area, fill it by
                                 zeros (default for hd media type on
                                 partitions and on removable disks)

                   mbr           put MBR table with one partition which
                                 starts at sector 0 (includes MBR itself)
                                 and spans whole disk device, needed only
                                 for non-removable hard disks used on
                                 Microsoft Windows systems (default for hd
                                 media type on non-removable hard disk
                                 without partitions), see section WHOLE DISK
                                 VS PARTITION

              (Option available since mkudffs 2.0)

       --strategy= strategy
              Specify the allocation strategy to use. Valid strategies are 4
              and 4096. If omitted, mkudffs strategy is based on the

       --spartable, --spartable= spartable-number
              Enable usage Sparing Table. Optionally specify also the number
              of sparing tables. Valid numbers are 1–4. When the spartable
              number is omitted then two tables are written to the disc. If
              the option is omitted then usage of Sparing Table depends on
              the media type. (Option prior to mkudffs 2.0 was available
              only for cdrw media type)

       --sparspace= num-of-entires
              Specify the number of entries in Sparing Table. If omitted,
              the default number of entries is 1024, but depends on the
              media type. (Option available since mkudffs 2.0)

       --packetlen= length
              Packet length in a number of blocks used for alignment. All
              continuous UDF structures would be aligned to packets. It
              specifies also the size of the Sparing Space and packet length
              in Sparing Table. It should match the device ECC/packet
              length. If omitted, default value for DVD discs is 16 blocks,
              for CD/BD discs it is 32 blocks and otherwise 1 block. (Option
              prior to mkudffs 2.1 was available only for cdrw and dvdrw
              media types)

       --vat  Enable usage of Virtual Allocation Table (VAT). If omitted,
              usage depends on the media type. (Option available since
              mkudffs 2.0)

              Close disc with Virtual Allocation Table. AVDP is written also
              to the end of the disc. By default, the disc with Virtual
              Allocation Table is not closed.

       --space= space
              Specify the Space Set. Unallocated Space Set is used for media
              which blocks may be allocated immediately. Freed Space Set is
              used for media which blocks needs to be specially
              prepared/erased before allocation. In Space Table is stored
              list of unallocated extents. In Space Bitmap is stored bitmap
              of unallocated blocks. Not used for VAT.

                   freedbitmap     Freed Bitmap

                   freedtable      Freed Table

                   unallocbitmap   Unallocated Bitmap (default)

                   unalloctable    Unallocated Table

       --ad= ad
              Specify the Allocation Descriptors of the root (/) directory.

                   inicb           Allocation Descriptors in ICB (default)

                   short           Short Allocation Descriptors

                   long            Long Allocation Descriptors

              Don't Use Extended File Entries for the root (/) directory.
              Affects only UDF 2.00 or higher. Must be specified after

              Treat identifier string options as strings encoded according
              to the current locale settings (default). Must be specified as
              the first argument. (Option available since mkudffs 2.0)

       --u8   Treat identifier string options as strings encoded in 8-bit
              OSTA Compressed Unicode format without leading Compression ID
              byte, which is equivalent to Latin1 (ISO-8859-1). Must be
              specified as first argument.

       --u16  Treat identifier string options as strings encoded in 16-bit
              OSTA Compressed Unicode format without leading Compression ID
              byte, which is equivalent to UTF-16BE. Note that it is not
              possible to include zero byte in command line options,
              therefore any character which has at least one zero byte
              cannot be supplied (this applies to all Latin1 characters).
              Must be specified as the first argument.

       --utf8 Treat identifier string options as strings encoded in UTF-8.
              Must be specified as the first argument. (Prior to mkudffs 2.0
              this was default option)


       UDF filesystem is natively supported by large amount of operating
       systems. See following compatibility table:

       │     Operating system       │ Maximum UDF revision for │
       │  Name   │     Version      │    read    │    write    │
       │         │ 2.3.17 – 2.4.5   │    2.00    │    2.00     │
       │Linux    │ 2.4.6 – 2.6.25   │    2.01    │    2.01     │
       │         │ 2.6.26 (and new) │    2.50    │    2.01     │
       │         │ 98/Me            │    1.02    │    none     │
       │Windows  │ 2000             │    1.50    │    none     │
       │         │ XP               │    2.01    │    none     │
       │         │ Vista (and new)  │    2.60    │    2.50     │
       │Mac OS   │ 8.1 – 8.5        │    1.02    │    none     │
       │         │ 8.6 – 9.2        │    1.50    │    1.50     │
       │         │ 10.0 – 10.3      │    1.50    │    1.50     │
       │Mac OS X │ 10.4             │    2.01    │    2.01     │
       │         │ 10.5 (and new)   │    2.60    │    2.50     │
       │FreeBSD  │ 5 (and new)      │    1.50    │    none     │
       │NetBSD   │ 4.0              │    2.60    │    none     │
       │         │ 5.0 (and new)    │    2.60    │    2.60     │
       │         │ 3.8 – 3.9        │    1.02    │             │
       │OpenBSD  │ 4.0 – 4.6        │    1.50    │    none     │
       │         │ 4.7 (and new)    │    2.60    │             │
       │Solaris  │ 7 (and new)      │    1.50    │    1.50     │
       │AIX      │ 5.2 (and new)    │    2.01    │    2.01     │
       Note that Windows 98 and Windows Me can read UDF filesystem only from
       CD and DVD optical discs, not from hard disks.

       In most cases, operating systems are unable to mount UDF filesystem
       if UDF block size differs from logical sector size of the device.
       Typically hard disks have sector size 512 bytes and optical media
       2048 bytes. Therefore UDF block size must match the logical sector
       size of the device.

       Linux kernel prior to version 2.6.30 used hardcoded UDF block size of
       2048 bytes independently of logical sector size, therefore it was not
       able to automatically mount UDF filesystem if block size differed
       from 2048. Since 2.6.30 and prior to 4.11 Linux kernel used a logical
       sector size of the device as UDF block size, plus it tried fallback
       to 2048. Since 4.11 it uses logical sector size and fallbacks to any
       valid block size between logical sector size and 4096. Therefore
       since version 2.6.30 Linux kernel can automatically mount UDF
       filesystems correctly if UDF block size matches device logical sector
       size and since version 4.11 can automatically also mount devices
       which sector size does not match UDF block size. In any case and also
       for Linux kernel prior to version 2.6.30, different UDF block size
       (which is not autodetected) can be manually specified via
       bs=blocksize mount parameter.

       UDF filesystem is supposed to be formatted on the whole media and not
       to the partitioned hard disk. Mac OS X systems enforce this rule and
       reject to automatically mount UDF filesystem unless it is formatted
       on the whole unpartitioned hard disk. Possible partition table (e.g.
       MBR or GPT) on disk with valid UDF filesystem is ignored. On the
       other hand, Microsoft Windows systems are unable to detect non-
       removable hard disks without MBR or GPT partition table. Removable
       disks do not have this restriction. A consequence is that non-
       removable hard disks formatted to UDF by Windows Vista+ are not
       recognized by Mac OS X systems and vice-versa. Note that manual mount
       of UDF partition on partitioned hard disk on Mac OS X system is
       possible and working (e.g. by running commands: mkdir
       /Volumes/DriveName && mount_udf /dev/disk1s1 /Volumes/DriveName). But
       there is no known way to mount an unpartitioned non-removable disk on
       Windows system.

       Thanks to reserved and unused UDF boot area (first 32kB of UDF
       filesystem) it is possible to deal with this problem, by putting MBR
       on such non-removable hard disk just for compatibility reasons with
       Windows. Such MBR table would contain one partition which starts at
       sector 0 (includes MBR itself) and spans whole disk device. So the
       whole disk device and also the first partition on disk points to same
       sectors. Therefore UDF filesystem can be mounted either from whole
       disk device (needed for Mac OS X systems) or from first partition
       (needed for Microsoft Windows systems).

       Linux kernel ignores MBR table if contains partition which starts at
       sector 0. Normally Linux kernel can detect and mount UDF filesystem
       either on a partition or on whole disk device. It does not have any

       mkudffs option --bootarea=mbr put such MBR table for compatibility
       with Microsoft Windows systems into disk when formatting.

       In most cases Logical Volume Identifier is used as UDF label. But
       Linux libblkid prior to version 2.26 used Volume Identifier.
       Therefore mkudffs --label for compatibility reasons set both Logical
       Volume Identifier and Volume Identifier.

       Linux libblkid prior to version 2.30 incorrectly processed non-ASCII
       identifier strings encoded in 8-bit OSTA Compressed Unicode format.
       Therefore mkudffs since version 2.0 for compatibility reasons tries
       to encode a non-ASCII identifier strings in 16-bit OSTA Compressed
       Unicode format and then fallbacks to 8-bit format.

       For more information about UDF Label and UUID see udflabel(8) section

EXIT STATUS         top

       mkudffs returns 0 if successful, non-zero if there are problems.

LIMITATIONS         top

       mkudffs cannot create UDF 2.50 Metadata partition, therefore it does
       not support UDF revisions higher than 2.01 for non Write Once media
       yet. So there is no support for Blu-ray discs which needs UDF 2.50
       (except for Blu-ray Disc Recordable which does not require Metadata

       mkudffs prior to version 2.2 was unable to process Unicode strings
       with code points above U+FFFF. When option --utf8 was specified then
       input strings were limited to 3-byte UTF-8 sequences and when option
       --u16 was specified then input strings were limited just to UCS-2BE
       strings (subset of UTF-16BE).

BUGS         top

       mkudffs prior to version 1.1 was unable to process non-ASCII
       characters from identifier strings in --utf8 mode, --vsid option was
       completely broken and --blocksize must have been manually specified
       for hard disks as default value was hardcoded for optical disks.
       mkudffs prior to version 2.0 generated broken and unreadable cdr disc

AUTHOR         top

       Ben Fennema
       Pali Rohár <>

AVAILABILITY         top

       mkudffs is part of the udftools package and is available from

SEE ALSO         top

       pktsetup(8), udflabel(8), cdrwtool(1), udfinfo(1), wrudf(1)

COLOPHON         top

       This page is part of the udftools (Linux tools for UDF filesystems
       and DVD/CD-R(W) drives) project.  Information about the project can
       be found at ⟨⟩.  If you have a bug
       report for this manual page, see
       ⟨⟩.  This page was obtained
       from the project's upstream Git repository
       ⟨⟩ on 2020-11-01.  (At that time,
       the date of the most recent commit that was found in the repository
       was 2020-10-27.)  If you discover any rendering problems in this HTML
       version of the page, or you believe there is a better or more up-to-
       date source for the page, or you have corrections or improvements to
       the information in this COLOPHON (which is not part of the original
       manual page), send a mail to

System Management Commands        udftools                        MKUDFFS(8)

Pages that refer to this page: udfinfo(1)wrudf(1)mount(8)udflabel(8)