Distributed Name Service (DNS) Management Programming Manual

Glossary
46958 Tandem Computers Incorporated Glossary–3
Composite-type component. A member of a set of subsystem-object types that make up
an instance of a particular composite type.
Composite-type name. The name assigned by the user to identify a composite type: for
example, ATM. An externalization of the owner . composite type number
construct.
Composite-type number. In DNS, an integer used to identify a composite type within the
context of the owner who defined the composite type. The owner . composite type
number pair always provides a unique identifier for the composite type that is
independent of the composite-type name assigned by a particular customer.
Developers of management applications may always use the owner . composite
type number pair to refer internally to the composite type; DNS provides a
programmatic command for translating the pair to the type name, and vice versa. This
approach assures portability for management applications without concern for
composite-type name conflicts.
Configuration file. A file that contains only configuration data, such as the DNS
configuration file.
Constant (DDL). A DDL object that associates a name with a number or string. When
DDL is used to create a set of definitions, a constant defined to DDL becomes a literal
or define in TAL, a level-01 variable in COBOL85, and a text variable in TACL. In the
definition files supplied by Tandem, DDL constants are used for command numbers,
object-type numbers, error numbers, subsystem numbers, token data-type numbers,
token numbers, and various other useful values.
Context, context information. The information required by a server to process a series of
requests from the same requester. Continuation of a response over multiple replies
from the server requires the server to send the context information to the requester,
and the requester to send that information back to the server to obtain each new reply.
See Context token.
Context-free server. A server that does not retain any information about previous
processing; it knows only about its processing of the current request message. For
instance, a context-free server performing a command on a list of objects and sending
its response in a series of reply messages does not retain the name of the last object it
processed in the last reply. The requester must therefore resend the command with a
context token that contains that information. A context-free server allows the
requester to interrupt or abandon the continuation of a series of replies.
Context-sensitive server. A server that retains information about previous processing.
For instance, in performing a command on a list of objects, a context-sensitive server
might retain, between reply messages, the name of the object it last processed.
Context-sensitive servers limit or complicate the requester’s ability to interrupt or
abandon the continuation of a series of replies.