Universal Disk Format

Universal Disk Format (UDF) is a CD-ROM file system standard that is required for DVD-ROMs. UDF is the 's replacement for the ISO 9660 file system used on CD-ROMs, but is mostly used on DVD. DVD multimedia disks use UDF to contain MPEG audio and video streams.

Description
For a computer to read video DVDs, a kernel driver is required for the drive, along with MPEG video support and a UDF driver. DVDs containing both UDF filesystems and ISO 9660 filesystems can be read without UDF support. UDF can also be used by CD-R and CD-RW recorders in mode.

History
Apple Computer adopted UDF in January 1998 with the release of Mac OS 8.1, the first version of classic Mac OS to support DVD-ROMs.

Mac OS X 10.5 (Leopard) was released in October 2007 with drivers for UDF 2.5, which added support for reading HD DVD and Blu-ray Discs through 3rd-party drives, though the included DVD Player software can only play HD DVD disks authored by DVD Studio Pro.