Universal Disk Format

Universal Disk Format (UDF) is a file system defined by the Optical Storage Technology Association. UDF is based on the ISO 13346 (ECMA-167) standard and is the successor to the ISO 9660 (CDFS) format.

UDF is used for removable media like DVD, CD, compact disc recordable (CD-R), compact disc rewritable (CD-RW), write once, read many (WORM), and magneto-optical (MO) discs. Because UDF is based on open standards, it is intended to facilitate data interchange between operating systems and between consumer devices. The standard supports a number of advanced features, including:

• Long and Unicode file names

• Deep directory trees

• Sparse files

• Large (64-bit) file sizes

• Access control lists (ACLs)

• Named streams

Windows XP Professional reads UDF versions 1.02, 1.50, 2.0, and 2.01 on CD, CD-R, CD-RW, DVD, DVD-RAM, and magneto-optical discs. Support is implemented in the Udfs.sys driver. If you have a DVD-RAM drive, you can use Windows XP Professional to format DVD-RAM discs by using FAT32. Windows XP Professional does not include built-in support for formatting DVD-RAM discs by using NTFS, although some third-party tools might enable this capability.

Windows XP Professional does not support writing to UDF volumes. In addition, Windows XP Professional does not implement the following UDF features:

• Named streams

• Access control lists

• Extended attributes

Note 

Windows XP Professional reads the File Create Time from an embedded FileTimes extended attribute recorded in a basic file entry.