ANSI/NISO Z39.50-1992                          ISSN: 1041-5653
(Revision of ANSI/NISO Z39.50-1988)

Application Service Definition and Protocol Specification for Open Systems Interconnection

For terms that are formally defined in other standards, the formal definition is given, italicized, and the standard is listed in parentheses. In those cases, descriptions and/or alternate definitions (indented) are sometimes provided. All of the definitions below including the alternate definitions apply only to the Information Retrieval application service and protocol, and only within the context of this standard.

APDU--See Application Protocol Data Unit.

Application Association--A cooperative relationship between two application-entity-invocations for the purpose of communication of information and coordination of their joint operation. This relationship is formed by the exchange of application-protocol-control-information using the Presentation-Service. (ISO 9545)

For the Information Retrieval service and protocol, an application association is analogous to an individual communication session between a database user and a database provider. Each association consists of an origin application and a target application, and these roles may not be reversed within an association.

Application Protocol--The rules governing the format and exchange of information between an origin and target application.

Application Protocol Control Information--The information conveyed by application protocol data units.

Application Protocol Data Unit-- A unit of data specified in an application-protocol and consisting of application-protocol-information and possibly application-user-data. (ISO 7498)

A unit of data passed between an origin and a target.

ASN.1--Abstract Syntax Notation One.

Conditionally Confirmed Service--A confirmed service in which the response might under certain conditions not occur.

Confirmed Service--A distinct part of the total IR-service that results in an explicit confirmation from the service-provider to the initiating service-user. (ISO TR 8509)

A service that consists of a request followed by a response. A confirmed service may be initiated by the origin, in which case it consists of a request by the origin followed by a response from the target; or it may be initiated by the target, in which case it consists of a request by the target followed by a response from the origin.

Database Provider--The application that provides access to a database local to that application.

Database User--The application that accesses a remote database.

IR--Information Retrieval

Origin Application--The application that initiates an association and is the source of requests during the association. The database user.

Name--A linguistic construct, expressed in some language, that corresponds to an object. A name denotes (i.e. identifies) the object to which it is bound.

Non-Confirmed Service--A distinct part of the total IR-service which does not result in an explicit confirmation from the service-provider to the initiating service-user. (ISO TR 8509)

A service that consists of a request only (not followed by a response). It may be initiated by the origin or the target.

Primitive--An abstract, implementation-independent representation of an interaction between the service-user and the service-provider. (ISO TR 8509)

Primitive Name--A kind of name, the internal structure of which is not required to be understood or to have significance to users of the name.

Result set--An ordered list of triples consisting of (a) an ordinal number corresponding to the position of the triple in the list, (b) a database name, and (c) a unique record identifier (of local significance only) within the database named in (b). A result set is formed by applying a search query.

RPN--Reverse Polish Notation

Service Provider--An abstract of the totality of those entities that provide a service to peer service-users. (ISO TR 8509)

(Note: the concept of service-provider is employed to facilitate the specification of protocol procedures. It is not analogous to the database provider, and it does not refer to providers of telecommunication services.)