Logical Name Table

From VSI OpenVMS Wiki
Revision as of 13:18, 2 June 2019 by Darya.zelenina (talk | contribs)
(diff) ← Older revision | Latest revision (diff) | Newer revision → (diff)
Jump to: navigation, search

A logical name table is a data structure that stores logical names. In addition to custom logical name tables that users can create, there exist the following types of logical name tables: process logical name table, job logical name table, group logical name table, system logical name table, and cluster logical name table. To display the hierarchy of logical name tables on your system, use SHOW LOGICAL/STRUCTURE. The name of a logical name table is a string of 1-32 characters.

Process Logical Name Table

Process logical name table stores logical names created by the current process and stays around for the life of the process.

Job Logical Name Table

Job logical name table stores logical names shared by processes in a job and stays around for the life of the job.

Group Logical Name Table

Group logical name table stores logical names shared by a UIC group members and stays around for the life of the system (until the system reboots). GRPNAM is required to modify the group logical name table; however, logicals there can be viewed and used by all members of the group.

System Logical Name Table

System logical name table stores systemwide logical names. It stays around for the life of the system. Privileges are required to modify the system logical name table.

Cluster Logical Name Table

Cluster logical name table stores clusterwide logical names.

Lookup Order

Logical names are looked up in the following order: process, job, group, system, cluster. As soon as the logical name is found, the search stops. For example, if the same logical name is defined in the process and system logical name tables, the process definition will be used.


A logical name table is also a protected object class, which means that a protection code can be defined for a logical name table. A logical name table can be accessible to only one process, or it can be shareable if its parent table is shareable. All shareable name tables are listed in the LNM$SYSTEM_DIRECTORY, the system directory table. It is shareable logical name tables that the operating system protects. Read, Write, Create, Delete, and Control access is available for logical name tables. Access and Creation auditing can be performed on logical name tables.

See also