X 120 mm BD Medium (Normative)
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# X 120 mm BD Medium (Normative)

This Annex defines the use of the UDF file systems with BD media in such a manner as to require a reader to be capable of reading all of the physical media types and UDF file system versions that are defined in this Annex, and a creator to be able to create at least one of those types of media and file system.

The media types supported are BD-RE and BD-R.

### Note

Capitalization in this annex may be inconsistent with other DICOM standards in order to be consistent with historical usage for terms in referenced documents.

Universal Disk Format (UDF) is a profile of the ECMA 167 3rd edition file system.

### Note

The ECMA 167 3rd edition is more recent than ISO 13346:1995, which is equivalent to ECMA 167 2nd edition.

## X.1 DICOM Mapping to Media Format

### X.1.1 Media Character Set

The character set used in UDF fields shall be the CS0 OSTA Compressed Unicode character set, required by the UDF standard.

### Note

1. The CS0 OSTA Unicode character set is defined in UDF and is a subset of Unicode 2.0.

2. UDF defines a specific form of compression of 8 and 16 bit Unicode characters that must be supported.

3. The character set defined elsewhere in this section for DICOM File-set fields is a subset of this character set. However other fields in the UDF file system, and other files in the UDF file system not in the DICOM File-set, may use characters beyond those defined by DICOM for File ID Components, including those encoded in 16 bits.

### X.1.2 DICOM File-set

One and only one DICOM File-set shall be stored on each side of a single piece of media.

A DICOM File-set is defined to be completely contained within one UDF File-set.

Only a single UDF File-set shall be present in the UDF Volume.

Each side of the media will comprise a single self-contained UDF Volume. That is the UDF Volume Set shall not consist of more than one UDF Volume.

Only a single UDF Partition shall be present on each side of the media.

### Note

Both sides of a single piece of media may be used for storing DICOM data, when separate DICOM File-sets are created.

### X.1.3 DICOM File ID Mapping

The UDF Standard provides a hierarchical structure for directories and files within directories. Each volume has a root directory that may contain references to both files and sub-directories. Sub-directories may contain reference to both files and other sub-directories.

#### X.1.3.1 File ID

PS3.10 defines a DICOM File ID Component as a string of 8 characters from a subset of the G0 repertoire of ISO 8859. Each of these File ID Components is mapped to a UDF File Identifier or Path Component in the OSTA CS0 character set.

### Note

This mapping is a subset of the MS-DOS mapping specified in UDF.

Filename extensions are not used in DICOM File ID Components, hence a UDF File Identifier shall not contain a File Extension or the '.' that would precede such a File Extension.

The maximum number of levels of a Resolved Path name in a UDF file-set shall be at most 8 levels, to comply with the definition of a DICOM File-set in PS3.10.

The File Version Number is always equal to 1, as specified by UDF.

#### X.1.3.2 DICOMDIR File

A DICOMDIR file in a DICOM File-set shall reside in the root directory of the directory hierarchy, as specified in PS3.10.

### X.1.4 DICOM File Management Information

No file management information beyond that specified in the UDF File Entry is required. In particular no Extended Attributes or Named Streams are required.

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