SPI Common Extensions Manual

Glossary
SPI Common Extensions Manual—427508-001
Glossary-13
Subsystem Control Point (SCP)
Subsystem Control Point (SCP). An intermediate management process used by many
Compaq subsystems. There can be several instances of this process. Applications
send commands to an instance of this process, which in turn sends them on to the
manager processes of the target subsystem. The SCP also processes a few
commands itself. It provides security features, version compatibility, support for tracing,
and support for applications implemented as process pairs.
subsystem definitions. The set of declarations available for use with a particular
subsystem that supports a token-oriented programmatic interface. See also definition
files and SPI standard definitions.
subsystem ID. A data structure that uniquely identifies a subsystem (including whether it is
a Compaq subsystem or a subsystem you write). It consists of the name of the owner
of the subsystem (the company that provides it), a subsystem number that denotes the
subsystem within the scope of its owner, and a subsystem version number. The
subsystem ID is an argument to most of the SPI procedures.
subsystem number. An integer that identifies a subsystem within the context of its owner.
The subsystem owner, the subsystem number, and the subsystem version number
make up the subsystem ID that uniquely identifies a subsystem.
subsystem owner. A value identifying the company that supplies a particular subsystem. It
consists of a name of up to eight characters, blank-filled on the right. For example, the
owner for all subsystems Compaq supplies is TANDEM. The subsystem owner, the
subsystem number, and the subsystem version number make up the subsystem ID
that uniquely identifies the subsystem.
Subsystem Programmatic Interface (SPI). A set of procedures and associated definition
files and a standard message protocol used to define common message-based
interfaces for communication between management applications and subsystems. It
includes procedures to build and decode specially formatted messages (see SPI
message); definition files in TAL, COBOL85, and TACL for inclusion in programs,
macros, and routines using the interface procedures; and definition files in DDL for
programmers writing their own subsystems.
subsystem version number. A 16-bit integer representing the software release version of
a subsystem. The subsystem version number is a field of the subsystem ID. If its value
is null (zero), the subsystem ID refers to any and all versions of the subsystem. See
version number.
subsystem-control token. A parameter token that influences how a subsystem performs a
command. For instance, in the START PATHWAY programmatic command, the
parameter ZPWY-TKN-DEF-PATHWAY is a subsystem-control token because it
determines whether a cold start or a cool start is performed. Likewise, the standard SPI
token ZSPI-TKN-ALLOW-TYPE, supported by some subsystems, is a subsystem-
control token. It determines under what conditions the subsystems continues command
processing on the next object in a sequence if errors or warnings occur. Compare with
response-control token.