SPI Programming Manual (G06.24+, H06.03+, J06.03+)

Introduction to SPI
SPI Programming Manual—427506-006
1-6
SPI Message Format
•
How requesters and servers should respond to error conditions
Communication between a management application and a subsystem follows the
standard HP requester-server model, with the management application in the role of
requester and the subsystem manager process in the role of server.
SPI is a general interface governed by many general rules and guidelines. This manual
describes the basic SPI protocol, the SPI procedures used to build and decode
messages, and the common data definitions used in SPI messages. An SPI interface
to a particular subsystem is usually based on a very specific implementation of these
generalities. For detailed information about the SPI interface to a particular subsystem,
see the management programming manual for that subsystem.
After composing an SPI message, an application (requester) uses standard
interprocess communication to send the message to the subsystem manager (server).
SPI Message Format
SPI messages have a common structure. Each message consists of a message
header followed by as many tokens as are necessary to convey information relevant to
the message. (The number of tokens is limited by the size of the message buffer.)
Figure 1-4. SPI Communication Through an Intermediate Process
VST004.vsd
A subsystem can have its commands and responses routed through an intermediate process.
Subsystem
Process
Subsystem
Process
Subsystem
Process
Legend
SPI Command
SPI Response
Intermediate
Routing
Process
Management
Application
Management
Application
Subsystem
Manager
Subsystem
Manager
Subsystem
Manager