File Identifier
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The applicable set of characters is specified in the description of the descriptor fields.
7.4.2 c-characters
The characters of the coded graphic character sets identified by the escape sequences in a Supplementary
Volume Descriptor are referred to as c-characters.
7.4.2.1 a1-characters
A subset of the c-characters will be referred to as a1-characters. This subset shall be subject to agreement
between the originator and the recipient of the volume.
7.4.2.2 d1-characters
A subset of the a1-characters will be referred to as d1-characters. This subset shall be subject to agreement
between the originator and the recipient of the volume.
7.4.3 Separators
The characters separating the components of a File Identifier shall be
SEPARATOR 1 represented by the bit combination (2E)
SEPARATOR 2 represented by the bit combination (3B)
7.4.4
Use of characters in descriptor fields
The characters in the fields of the following descriptors shall be a-characters or d-characters as specified in
clause 9.
- Directory Records within a Directory Hierarchy that is identified in a Primary Volume Descriptor;
- Path Table Records within a Path Table Group identified in a Primary Volume Descriptor;
- Extended Attribute Records identified in a directory of a Directory Hierarchy that is identified in a Primary
Volume Descriptor.
The characters in the fields of the following descriptors shall be a1-characters or d1-characters as specified in
clause 9.
- Directory Records within a Directory Hierarchy that is identified in a Supplementary Volume Descriptor;
- Path Table Records within a Path Table Group identified in a Supplementary Volume Descriptor;
- Extended Attribute Records identified in a directory of a Directory Hierarchy that is identified in a
Supplementary Volume Descriptor.
7.4.5
Justification of characters
In each fixed-length field the content of which is specified by this Standard to be characters, the characters shall
be left-justified and any remaining byte positions on the right shall be set to (20).
7.5 File
Identifier
7.5.1
File Identifier format
A File Identifier shall consist of the following sequence:
- File Name: A sequence of zero or more d-characters or d1-characters;
- SEPARATOR 1;
- File Name Extension: A sequence of zero or more d-characters or d1-characters;
- SEPARATOR 2;
- File Version Number: Digits representing a number from 1 to 32 767.
This sequence shall meet the following requirements:
- If no characters are specified for the File Name then the File Name Extension shall consist of at least one
character.
- If no characters are specified for the File Name Extension then the File Name shall consist of at least one
character.
