All approved UDF 2.60 DCNs

All approved UDF 2.60 DCNs
6.y.2 Requirements for Blu-ray Disc Rewritable Format (BD-RE)
A Blu-ray Rewritable disc (BD-RE) is a non-sequential recording medium. A BD-RE
drive performs read modify write operations when needed. Defect free logical space is
provided by a BD-RE drive which performs defect management using the linear
replacement algorithm.
The BD-RE File System Format shall comply with UDF revision 2.50 and has the
following additional requirements:
For Volume Structure:
1. The Partition Descriptor Access Type shall be 4 (overwritable).
For File Structure:
2. An Unallocated Space Bitmap shall be recorded, no Unallocated Space Table.
NOTE: Duplication of Metadata File data is optional. When the user requires
robustness rather than write performance, it is recommended that duplication is used and
that Metadata File and Metadata Mirror File data and descriptors are recorded at the
physically inner radius area and outer radius area, respectively.
Requirements for Defect Management:
Spare Area shall be assigned on a Blu-ray Rewritable disc, as the UDF file system
requires Drive Defect Management by the drive system. In general, Spare Areas with the
default size are assigned at format time.
NOTE: When the available clusters in Spare Area are exhausted, additional Spare Area
can be allocated after all data is backed up to the other media. On the other hand, if a
special utility tool can move some file data and volume structure on the disc in order to
shorten the volume space, the Spare Area can be expanded preserving the file data on the
disc.
All approved UDF 2.60 DCNs 39 February 28, 2005