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Directory hierarchy

9 -

- information to locate a File Section;
- information to locate any Extended Attribute Record associated with the File Section;
- the identification of the file;
- certain attributes of the file;
- certain attributes of the File Section.

The first or only Directory Record recorded in a Logical Sector shall begin at the first byte of the first Data
Field of that Logical Sector. Each subsequent Directory Record recorded in that Logical Sector shall begin at
the byte immediately following the last byte of the preceding Directory Record in that Logical Sector. Each
Directory Record shall end in the Logical Sector in which it begins. Unused byte positions after the last
Directory Record in a Logical Sector shall be set to (00).

6.8.1.2

Order of Directory Records
The records in a directory shall be ordered according to 9.3.

6.8.1.3 Directory

length

The length of a directory shall be the sum of

- the lengths of all Directory Records in the directory;
- the number of unused byte positions after the last Directory Record in all Logical Sectors in which the

directory is recorded.

6.8.2 Directory

Hierarchy

A Directory Hierarchy shall be a set of directories related to each other as follows.

The root of the hierarchy, called the Root Directory, shall be a directory identified either in a Primary Volume
Descriptor or in a Supplementary Volume Descriptor.

Each directory, other than the Root Directory, shall be identified by a record in another directory.

A directory identifying another directory shall be called the Parent Directory of the identified directory. Each
directory shall contain a record which identifies its Parent Directory. Different directories may have the same
Parent Directory.

A hierarchical relationship shall exist between the Root Directory and all other directories:

ROOT

SUB 1

SUB 2

SUB 3

The hierarchy shall consist of a number of levels (i.e. for n levels: level 1, level 2, ..., level n). The Root
Directory shall be the only directory at level 1 of the hierarchy.

If a Directory is at level m of the hierarchy, its Parent Directory shall be at level (m - 1). The Parent Directory of
the Root Directory shall be the Root Directory.

6.8.2.1

Depth of Directory Hierarchy
The number of levels in the hierarchy shall not exceed eight. In addition, for each file recorded, the sum of
the following shall not exceed 255:

- the length of the File Identifier (see 7.5.2);
- the length of the Directory Identifiers (see 7.6) of all relevant directories;
- the number of relevant directories.

6.8.2.2

Identification of directories
For a Root Directory: