Logical Name
A logical name is a string that can be used in place of another name to represent system objects such as files, directories, devices, or queues. For example, you might assign a logical name to your default disk and directory.
Use
Logical names serve two main functions: they increase readability and file independence.
You can define commonly used files, directories, and devices with short, meaningful logical names. Such names are easier to remember and type than the full file specifications. You can define names that you use frequently in your login command procedure. A system manager can define names that people use frequently in the system startup command procedure.
You can use logical names to keep your programs and command procedures independent of physical file specifications. For example, if a command procedure references the logical name ACCOUNTS, you can equate ACCOUNTS to any file on any disk.
Characteristics
Logical names have the following characteristics:
- Are equated to strings (called equivalence strings or equivalence names) or a list of equivalence strings (called search lists). When you use a logical name, the equivalence string is substituted for the logical name.
- Are stored in default logical name tables or logical name tables that you create.
- Can be shorthand for long file specifications.
- Can be defined by you or by the system.
- Can be used to keep programs and command procedures independent of physical file specifications. For example, if a command procedure references the logical name ACCOUNTS, you can equate ACCOUNTS to any file on any disk before executing the command procedure.
Logical name tables
- Cluster logical name table
- System logical name table
- Group logical name table
- Process logical name table
