OSI/AS Management Programming Manual

Glossary
Glossary-18 056785 Tandem Computers Incorporated
Response record. In DSM programmatic interfaces, a set of response tokens, usually
describing the results of performing a command on one object. Every response record
in a response from a Tandem subsystem contains a return token; a response record can
also contain error lists that include error tokens. A response can consist of multiple
response records, spread across one or more response messages. A response record
cannot be split between two response messages. If there are multiple response records
in a response message, each response record is enclosed in a data list. See also data
list. Each response record is required to contain a return token. See also return token.
Resynchronization. The Session Layer feature that allows an application to reset a
connection to a defined state after a problem has occurred. This action includes
reassignment of tokens, setting the synchronization point serial number to a new
value, and purging all undelivered data, or going back to a defined previous
synchronization point.
Return token. In DSM programmatic interfaces, the token that indicates whether a
command was successful and, if not, why it failed. The token code for the return
token is ZSPI-TKN-RETCODE. Its value consists of a single integer field. Compare
error token.
SAP (service access point). The access means by which a pair of communicating entities
in adjacent layers use or provide services.
SCF (Subsystem Control Facility). A part of DSM, used to provide a common, interactive
management interface for configuring, controlling, and collecting information from
Tandem data communications products.
SCP (Subsystem Control Point). In DSM, the management process for all Tandem data
communications subsystems. There can be several instances of this process.
Applications using SPI send all commands for data communications subsystems to an
instance of this process, which in turn sends the commands on to the manager
processes of the target subsystems. SCP also processes a few commands itself. It
provides security features, version compatibility, support for tracing, and support for
applications implemented as NonStop process pairs. See also management process or
manager process.
SDU (service data unit). Information passed across the network to a peer entity and then
up to the next layer.
Sensitive command. In DSM, a command that can be issued only by a restricted set of
Guardian 90 users, such as the owner of a subsystem process. For Tandem 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. Compare nonsensitive command.
Service. A set of primitives (operations) that a 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. Compare protocol.