Universal Disk Format

The Universal Disk Format (UDF ) is a by the Optical Storage Technology Association ( OSTA ) developed and specified, used mainly for DVDs, platform-independent file system that is increasingly replacing the older ISO 9660 format. UDF was standardized as ISO 13346, which is also known under the name of ECMA -167. In principle, however UDF finds useful application for all RW and RO media, provided that the operating system you are using supports UDF.

Compared to ISO 9660 fall at UDF away some limitations:

  • File names can be up to 255 characters long in UDF, with a total of 64,000 possible characters can be selected. ( For comparison: ISO 9660 Level 1: 8 characters for the file name plus 3 for the filename extension, at ISO 9660 Level 2: up to 31 ISO character, in Joliet. , Up to 64 Unicode characters )
  • No limit to the directory depth to eight levels; maximum path length: 1023 characters.
  • Support for 8 - and 16 -bit character sets.
  • Distinction of upper and lower case letters in file names.
  • Storing the file attributes of different operating systems.
  • Expansion of the potential size of the file system in the terabyte range; Repeal the maximum file size of two gigabytes.
  • Optimizations for recording to DVD ± R / DVD- RW and DVD-RAM.

Compatibility

A compatibility UDF media to ISO 9660 can be made by MicroUDF DVD with an ISO 9660 Level 3- Layer; so the resulting UDF / ISO Bridge Disc can then, depending on the driver, identified as UDF or ISO medium. Through the UDF / ISO Bridge is an older operating system or device, such as Windows 95 or a common DVD player, able to read the files contained in the ISO 9660 file system, while more modern operating systems or devices which also contained UDF use the file system. All newer versions of Windows already do not support read access to UDF, but in each version. Linux Kernel 2.6, Mac OS 8.6 support UDF read and write at least until UDF 1.50 Windows Vista from 2:50 to UDF. Linux can read UDF to version 2.60, but UDF 2.50 is the maximum of what mkudffs can create the UDF component of all open source burning software. UDF file systems versions higher than 2.01 can not be described by the Linux UDF driver itself. To create and burn UDF 2.5 and 2.6 on Linux, the commercial Nero Linux 4 until now the only option.

UDF-CDs/DVDs/ISOs can be, for example, with the burning program Nero (Windows, Linux), Toast (Mac OS), or K3b (Linux) to create. As a free alternative for Windows also ImgBurn or CDBurnerXP can be used in addition to the built-in burning function.

The UDF format is also the preferred file system for packet writing. With packet writing, it is possible to use a writable optical media like a removable hard drive or a USB stick. Packet writing by UDF is currently supported by nearly all operating systems, most prominent exception is Windows XP, but for which there are numerous packet writing programs from third-party vendors.

The recording feature of Windows Vista formatted CD - Rs / DVD-Rs, even without any user intervention, as UDF, sometimes even before the job for writing a file was added to the medium. The CDs / DVDs so automatically created are incompatible with Windows 2000 and earlier operating systems.

Versions

Over the years, the following versions have been released from UDF:

UDF 1.0x is usually found together with ISO 9660 and UDF / ISO Bridge, in order to achieve better compatibility with older operating systems and devices.

For use as replacement disks, such as DVD-RAM or Packet writing on CD- R ( W) and DVD ± R ( W), UDF is suitable only from version 1.50. UDF 1:50 but 2000 Reading and Windows Vista also writing, Mac OS from Mac OS 8.6 to read and write, Mac OS X 10.4 UDF 2.0, 10.5 and UDF 2.6 only of modern operating systems (Windows starting with Windows, Linux Kernel 2.4 or reading and from 2.6 kernel also write, but only up to UDF 2.01 UDF 2.60 read support from kernel 2.6).

Joliet (file system) Packet-Writing CD-R CD-ROM Blu-ray Disc recordable ISO Master Live File System
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