SPI Common Extensions Manual
SPI Common Extensions Manual—427508-001
1-1
1 Introduction to SPI Extensions
The Subsystem Programmatic Interface (SPI), a central component of the NonStop
Kernel Distributed System Management (DSM) architecture, is the path that
management applications and subsystems use to exchange control/inquiry messages
and event messages. Its basic features are described in the
SPI Programming Manual
.
Basic SPI provides fundamental capabilities but leaves many design and
implementation decisions for individual subsystem designers.
The SPI extensions in this manual promote standard SPI interfaces by formalizing and
regulating a number of issues that are not at all or only partially regulated by basic SPI.
Review of Basic SPI
SPI is a programmatic interface that facilitates automated management of subsystems.
SPI, which governs communications between management applications and the
subsystems they manage, consists of:
•
A standard message format
•
A standard message protocol
•
A standard unit of information—the token
•
Procedures for composing and decomposing messages
•
Data definitions for commonly used data structures
•
Rules and guidelines governing message content and protocol
Subsystems
A subsystem is a process or group of related processes that controls a set of related
objects. A typical NonStop Kernel subsystem controls objects such as lines, circuits, or
terminals.
Subsystem Objects
An object is a well-defined logical or physical entity such as a device, communications
line, logical subdevice, process, processor, file, or transaction. Most objects are
controlled by subsystems. A subsystem itself can be considered an object.
SPI is designed to allow programmatic management of subsystem objects—that is,
objects controlled by a subsystem. Some subsystem objects are real objects, such as
lines, and some are logical objects, such as subdevices (SUs). Some are configured
objects, such as network routes, and some are not, such as SNA sessions.
Topic Page
Review of Basic SPI
1-1
Overview of Extended SPI 1-5