Elements of a CDS Command

Control Program Verbs
The following is a list of the definitions of verbs used in control program commands:

add
Adds a value to a modifiable, set-valued attribute

clear
Removes knowledge of a cached clearinghouse or cached server from memory

create
Creates an entity

define
Creates knowledge of a locally cached server

delete
Deletes an entity

disable
Stops operation of a clerk or server

dump
Displays the contents of a clerk cache

list
Displays a list of specified entity names

remove
Removes a value from a set-valued or single-valued attribute

set
Changes the value of a modifiable, single-valued attribute

show
Displays attribute information

CDS Entities
Any individually manageable piece of CDS is called an entity. A set of commands exists for each entity. The following is a list of the entities and a description of what each entity represents:

Cached Clearinghouse
A cached clearinghouse is a clearinghouse that a clerk has discovered and cached. A clerk can learn about clearinghouses as a result of configuration information, advertisements received on a LAN, or during the process of finding a name.

Cached Server
A cached server is a server that a clerk has cached as a result of manual configuration through the control program.

Child
A child pointer connects a parent and child directory in a hierarchical namespace. The child pointer is stored in the parent directory and has the same name as the child directory.

Clearinghouse
A clearinghouse is a database that contains a collection of directory replicas at a particular server.

Clerk
The clerk is the interface between client applications and servers.

Directory
A directory contains child, object, and link entries that are logically stored under one name (the directory name).

Link
A soft link is a pointer providing an alternate name for an object entry, directory, or other soft link.

Object
An object entry represents a resource (for example, an application) that is named in the namespace.

Replica
A replica is a copy of a directory. Each copy, including the original or master, is referred to as a replica.

Server
A server handles lookup requests from clerks and maintains the contents of the clearinghouse or clearinghouses at its node.

CDS Entity Attributes
Every CDS entity has attributes, which are pieces or sets of data associated with that entity. Attributes can reflect or affect the operational behavior of an entity, record the number of times a particular event or problem occurred since the entity was last enabled, and uniquely distinguish an entity from any other entity. Some attributes have a single value; others contain a set of values.

CDS attributes are identified by ISO object identifiers (OIDs). Every CDS attribute name maps to an OID and a corresponding data type. Usually, client applications define the name of an attribute and its data type. Application programmers should never need to modify (except for the purpose of foreign language translation) the existing CDS labels associated with the unique OIDs in the OSF DCE Administration Guide - Core Components. However, programmers can obtain new OIDs from the appropriate allocation authority, create new attributes for their own object entries, and then append them to the existing list. The OID and data type of each attribute are stored in the file /opt/dcelocal/etc/cds_attributes. Descriptions of the CDS data types that applications can use are in the cdsclerk.h file.

All entities have show commands that you can use to display the names and values of specific attributes or all attributes. When you display an attribute that has more than one value, the show command lists each value for the attribute separately. When there are multiple values for an attribute, the command first lists the attribute name on a line ending with a colon, then the parts of the value.

For more information about CDS attributes, see the DCE Directory Service module in the OSF DCE Administration Guide - Core Components.