OSI/AS Programming Manual

Glossary
056783 Tandem Computers Incorporated Glossary-17
PSAP (presentation service access point). A network-unique, physical address in the
Presentation Layer through which connections are established and maintained. Also
called presentation address.
PSEL (presentation selector). A logical address in the Presentation Layer through which
presentation services are made available. A single PSEL can service one or more
connections simultaneously.
PTrace. A Tandem program used to display trace files created through the use of the
CMI or SCF Trace commands.
Register request. A request made by APS on behalf of an application, for the OSI
manager process to configure the resources necessary for that application to
communicate using the OSI/AS subsystem. A register request is generated as a result
of a call to APS_ASSOC_CONNECTREQ_ or APS_ASSOC_ATTACH_.
Release token. One of the four types of Session Layer tokens that are associated with
functional units. See Token and Functional unit.
Remote address. The terms remote address and local address refer to the two endpoints
of a connection. A remote address is the address of the end-system which is
considered remote with respect to the user.
Remote system. (1) Any end system or subsystem to which a connection can be
established. See also end system.
(2) Any system, within an Expand network, that is not the local system.
Request primitive. A primitive issued when a service user (entity) wants the service to
do some work. This is one of four types of service primitives. See also service
primitive.
Responder, responding user. The entity that responds to a connect request (this may be
on behalf of the entity that was actually called, that is, a different entity from that
responding). Initiators and responders are defined with respect to a single connection.
Some entities can be both an initiator and a responder simultaneously, but not over the
same connection. See also called address or calling address. Contrast initiator.
Compare calling user or called user.
Responding address. The address that responds to a connect request. See also called
address or calling address.
Response. (1) See response primitive.
(2) In DSM, the information or confirmation supplied (as part of a response message)
to an application by a subsystem in reaction to a DSM command.
Response message. An SPI message sent from a subsystem to an application program
in reaction to a command message. Compare command message or event message.
Response primitive. A primitive issued when a service user (entity) wants to respond to
an event. This is for confirmed services only. This is one of four types of service
primitives. See also service primitive.