Universal Disk Format

Universal Disk Format (UDF) is the Optical Storage Technology Association (OSTA) supported group of ISO/IEC 13346.

UDF also addresses ECMA-167, which is equivalent to ISO 13346. UDF is a writable file format that provides true space reclamation capabilities as well as file and directory-level security. This section contains detailed information about the implementation of UDF for directly attached (C4x) 3995 optical media libraries as well as for a DVD-RAM device.

Note: Although not accessible through IBM i operating system, CD and DVD media that are created using the supplementary volume descriptor of ISO 9660 may be accessible in a system. You can access them through an integrated system.

Media formatted with UDF supports the concept of time zones. Before V6R1, i5/OS stored the file and volume dates on optical media using machine time, with no reference to the time zone. Beginning in V6R1, Coordinated Universal Time (UTC) is recorded on optical media with the UDF media format, and times stored in releases before V6R1 are interpreted as UTC. As a result, those times stored in previous releases on UDF media might be off by up to 23 hours.