1* 2* Documentation/filesystems/udf.txt 3* 4 5If you encounter problems with reading UDF discs using this driver, 6please report them according to MAINTAINERS file. 7 8Write support requires a block driver which supports writing. Currently 9dvd+rw drives and media support true random sector writes, and so a udf 10filesystem on such devices can be directly mounted read/write. CD-RW 11media however, does not support this. Instead the media can be formatted 12for packet mode using the utility cdrwtool, then the pktcdvd driver can 13be bound to the underlying cd device to provide the required buffering 14and read-modify-write cycles to allow the filesystem random sector writes 15while providing the hardware with only full packet writes. While not 16required for dvd+rw media, use of the pktcdvd driver often enhances 17performance due to very poor read-modify-write support supplied internally 18by drive firmware. 19 20------------------------------------------------------------------------------- 21The following mount options are supported: 22 23 gid= Set the default group. 24 umask= Set the default umask. 25 mode= Set the default file permissions. 26 dmode= Set the default directory permissions. 27 uid= Set the default user. 28 bs= Set the block size. 29 unhide Show otherwise hidden files. 30 undelete Show deleted files in lists. 31 adinicb Embed data in the inode (default) 32 noadinicb Don't embed data in the inode 33 shortad Use short ad's 34 longad Use long ad's (default) 35 nostrict Unset strict conformance 36 iocharset= Set the NLS character set 37 38The uid= and gid= options need a bit more explaining. They will accept a 39decimal numeric value and all inodes on that mount will then appear as 40belonging to that uid and gid. Mount options also accept the string "forget". 41The forget option causes all IDs to be written to disk as -1 which is a way 42of UDF standard to indicate that IDs are not supported for these files . 43 44For typical desktop use of removable media, you should set the ID to that of 45the interactively logged on user, and also specify the forget option. This way 46the interactive user will always see the files on the disk as belonging to him. 47 48The remaining are for debugging and disaster recovery: 49 50 novrs Skip volume sequence recognition 51 52The following expect a offset from 0. 53 54 session= Set the CDROM session (default= last session) 55 anchor= Override standard anchor location. (default= 256) 56 lastblock= Set the last block of the filesystem/ 57 58------------------------------------------------------------------------------- 59 60 61For the latest version and toolset see: 62 https://github.com/pali/udftools 63 64Documentation on UDF and ECMA 167 is available FREE from: 65 http://www.osta.org/ 66 http://www.ecma-international.org/ 67