SPI Common Extensions Manual

Extended SPI Concepts

SPI Common Extensions Manual—427508-001

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Configured and Nonconfigured Objects

To better define how they respond to certain commands, objects are classified

according to their mode of creation:

•

A configured object already exists when its controlling subsystem completes

initialization or is created in response to a command issued through the SPI

management interface.

A configured object meets any of these criteria:

The object is defined as part of the system image by the SYSGEN process and

therefore is created during system startup.

The object is defined during subsystem initialization when the subsystem might

read configuration information from a file or extract it from parameters supplied

in its startup message.

The object is created in response to an SPI ADD command.

•

A nonconfigured object comes into existence after its controlling subsystem is

already running and is created in response to activity outside the SPI management

interface (for example, in response to a command interpreter RUN command).

Links Between Objects

A link is any sort of connection that lets information flow between objects. The objects

must exist for the link to exist. There are two kinds of links:

•

An implicit link between objects automatically exists when the two objects exist. No

additional steps are required to allow information to flow between the objects.

•

An explicit link needs to be established by command (CONNECT, for example)

after the objects themselves are created.

Object Types

Objects are classified by type. The object type, combined with the subsystem ID and

the names of the object and its manager process, uniquely identify each object on a

system. Object types can represent real objects, such as ZCOM-OBJ-LINE; logical

objects, such as ZCOM-OBJ-SU; or logical constructs, such as ZCOM-OBJ-TASK.

The object types used by NonStop Kernel subsystems are defined in the DDL

definition file named ZCOMDDL. For each type, these items are defined:

•

A mnemonic name (objtype in ZCOM-OBJ-objtype).

•

A constant (ZCOM-OBJ-objtype). An object type is declared in a command by

assigning this value to the header token ZSPI-TKN-OBJECT-TYPE and in a

response by assigning it to ZCOM-TKN-OBJTYPE.