OSI/MHS Configuration and Management Manual

OSI/MHS Configuration and Management Manual—424827-003
Glossary-28
provides security features, version compatibility, support for tracing, and support for
applications implemented as NonStop process pairs.
segment. See string segment.
selector. In OSI, an address component that refers to one or more service access points
(SAPs) of the Transport, Session, or Presentation Layer and is used to establish and
maintain connections. Remote systems and local users specify the selectors as part of
an address called the “n-address.” See also SAP.
send file. In the P7 API, a file used for sending data to the OSI/MHS subsystem. The file
number is returned by a call to the LOS_OPEN_ procedure. See also result file.
sensitive command. In DSM, a command that can be issued only by a restricted set of
operating system users, such as the owner of a subsystem process. For HP NonStop
data communications subsystems, the sensitive commands are those that can change
the state or configuration of objects, start or stop tracing, or change the values of
statistics counters. See also nonsensitive command.
service. A set of primitives (operations) that an OSI layer provides to the layer above it. The
service defines what operations the layer can perform on behalf of its users, but not
how these operations are implemented. A service relates to an interface between two
layers, with the lower layer being the service provider and the upper layer being the
service user. See also protocol.
The GPI and P7 API are examples of services available to applications. In both cases,
the service consists of a process and the library procedures that provide the
application interface to that process.
service access point. See SAP.
service element. In OSI, a feature or function defined as part of a service.
service primitive. In OSI, an abstract, implementation-independent interaction between a
service user and a service provider. Service primitives describe the sequences of
events between adjacent layers that occur through the service access point (SAP).
There are four types of service primitives; see confirm primitive, indication primitive,
request primitive, or response primitive.
session. A temporary logical connection between a user and a software product, or between
communicating processes.
In the GPI, an interaction between a client program and the GPI, established when a
client program successfully calls the GPI_OPEN_ procedure. Once a session is
established, the client program can request GPI services by calling other GPI
procedures. A session is ended by calling the GPI_CLOSE_ procedure.