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The mkisofs tool is used for premastering iso9660 filesystems which are used on CD or DVD. The output of mkisofs can be used in two ways. One, a file can be created for later recording onto a blank CD media. Two, mkisofs and cdrecord can be chained together with a pipe. The output of mkisofs is then sent to a CDROM writer with a utility such as cdrtools


Pad the end of the whole image by 150 sectors (300 kB). If the option -B is used, then there is a padding at the end of the iso9660 partition and before the beginning of the boot partitions. The size of this padding is chosen to make the first boot partition start on a sector number that is a multiple of 16.

The padding is needed as many operating systems (e.g. Linux) implement read ahead bugs in their filesystem I/O. These bugs result in read errors on one or more files that are located at the end of a track. They are usually present when the CD is written in Track at Once mode or when the disk is written as mixed mode CD where an audio track follows the data track.

To avoid problems with I/O error on the last file on the filesystem, the -pad option has been made the default.


Allow full 31 character filenames. Normally the ISO9660 filename will be in an 8.3 format which is compatible with MS-DOS, even though the ISO9660 standard allows filenames of up to 31 characters. If you use this option, the disc may be difficult to use on a MS-DOS system, but this comes in handy on some other systems (such as the Amiga). Use with caution.


This is like the -R option, but file ownership and modes are set to more useful values. The uid and gid are set to zero, because they are usually only useful on the author's system, and not useful to the client. All the file read bits are set true, so that files and directories are globally readable on the client. If any execute bit is set for a file, set all of the execute bits, so that executables are globally executable on the client. If any search bit is set for a directory, set all of the search bits, so that directories are globally searchable on the client. All write bits are cleared, because the CD-Rom will be mounted read-only in any case. If any of the special mode bits are set, clear them, because file locks are not useful on a read-only file system, and set-id bits are not desirable for uid 0 or gid 0. When used on Win32, the execute bit is set on all files. This is a result of the lack of file permissions on Win32 and the Cygwin POSIX emulation layer. See also -uid -gid, -dir-mode, -file-mode and -new-dir-mode.


Generate Joliet directory records in addition to regular iso9660 file names. This is primarily useful when the discs are to be used on Windows-NT or Windows-95 machines. The Joliet filenames are specified in Unicode and each path component can be up to 64 Unicode characters long. Note that Joliet is no standard - CD's that use only Joliet extensions but no standard Rock Ridge extensions may usually only be used on Microsoft Win32 systems. Furthermore, the fact that the filenames are limited to 64 characters and the fact that Joliet uses the UTF-16 coding for Unicode characters causes interoperability problems.


Verbose execution. If given twice on the command line, extra debug information will be printed.


Specifies the volume ID (volume name or label) to be written into the master block. There is space on the disc for 32 characters of information. This parameter can also be set in the file .mkisofsrc with VOLI=id. If specified in both places, the command line version is used. Note that if you assign a volume ID, this is the name that will be used as the mount point used by the Solaris volume management system and the name that is assigned to the disc on a Microsoft Win32 or Apple Mac platform.


Specifies that the boot image used to create "El Torito" bootable CDs is a 'no emulation' image. The system will load and execute this image without performing any disk emulation.


Specifies the number of "virtual" (512-byte) sectors to load in no-emulation mode. The default is to load the entire boot file. Some BIOSes may have problems if this is not a multiple of 4.


Specifies that a 56-byte table with information of the CD-ROM layout will be patched in at offset 8 in the boot file. If this option is given, the boot file is modified in the source filesystem, so make sure to make a copy if this file cannot be easily regenerated! See the EL TORITO BOOT INFO TABLE section for a description of this table.


Specifies the path and filename of the boot image to be used when making an "El Torito" bootable CD. The pathname must be relative to the source path specified to mkisofs. This option is required to make an "El Torito" bootable CD. The boot image must be exactly the size of either a 1200, 1440, or a 2880 kB floppy, and mkisofs will use this size when creating the output iso9660 filesystem. It is assumed that the first 512 byte sector should be read from the boot image (it is essentially emulating a normal floppy drive). This will work, for example, if the boot image is a LILO based boot floppy.

If the boot image is not an image of a floppy, you need to add one of the options: -hard-disk-boot or -no-emul-boot. If the system should not boot off the emulated disk, use -no-boot.

If the -sort option has not been specified, the boot images are sorted with low priority (+2) to the beginning of the medium. If you don't like this, you need to specify a sort weight of 0 for the boot images.


Specifies the path and filename of the boot catalog to be used when making an "El Torito" bootable CD. The pathname must be relative to the source path specified to mkisofs. This option is required to make a bootable CD. This file will be inserted into the output tree and not created in the source filesystem, so be sure the specified filename does not conflict with an existing file, as it will be excluded. Usually a name like "boot.catalog" is chosen.

If the -sort option has not been specified, the boot catalog sorted with low priority (+1) to the beginning of the medium. If you don't like this, you need to specify a sort weight of 0 for the boot catalog.


is the name of the file to which the iso9660 filesystem image should be written. This can be a disk file, a tape drive, or it can correspond directly to the device name of the optical disc writer. If not specified, stdout is used. Note that the output can also be a block special device for a regular disk drive, in which case the disk partition can be mounted and examined to ensure that the premastering was done correctly.



Generate SUSP and RR records using the Rock Ridge protocol to further describe the files on the iso9660 filesystem.


Cache inode and device numbers to find hard links to files. If mkisofs finds a hard link (a file with multiple names), then the file will only appear once on the CD. This helps to save space on the CD. The option -cache-inodes is default on UNIX like operating systems. Be careful when using this option on a filesystem without unique inode numbers as it may result in files containing the wrong content on CD.


Do not include backup files files on the iso9660 filesystem. If the -no-bak option is specified, files that contain the characters '~' or '#' or end in '.bak' will not be included (these are typically backup files for editors under unix).


Rename the directory RR_MOVED to .rr_moved in the Rock Ridge tree. It seems to be impossible to completely hide the RR_MOVED directory from the Rock Ridge tree. This option only makes the visible tree better to understand for people who don't know what this directory is for. If you need to have no RR_MOVED directory at all, you should use the -D option. Note that in case that the -D option has been specified, the resulting filesystem is not ISO9660 level-1 compliant and will not be readable on MS-DOS. See also NOTES section for more information on the RR_MOVED directory.


Allows "Untranslated" filenames, completely violating the iso9660 standards described above. Forces on the -d, -l, -N, -allow-leading-dots, -relaxed-filenames, -allow-lowercase, -allow-multidot and -no-iso-translate flags. It allows more than one '.' character in the filename, as well as mixed case filenames. This is useful on HP-UX system, where the built-in CDFS filesystem does not recognize ANY extensions. Use with extreme caution.