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

SPI Programming Manual—427506-006
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1 Introduction to SPI
This section provides an overview of the Subsystem Programmatic Interface:
The Components of SPI
The Subsystem Programmatic Interface (SPI), a central component of the Distributed
System Management (DSM) architecture, is the path that management applications
and subsystems use to exchange command-response messages and event
messages.
A Programmatic Interface
HP provides interactive text interfaces to most of its subsystems for the HP NonStop
Operating System. TMFCOM, PATHCOM, and the Subsystem Control Facility (SCF)
are examples. These text-based interfaces provide needed information in a form
readable by human operators on terminals, printers, and other display devices. When a
program communicates with a human operator, it is appropriate for the communication
to be based on native-language text. However, text-based messages are not well
suited for processing by a program. Programs can be written to parse text strings (and
many programs process messages intended to be read by an operator), but it is more
efficient for them to process messages containing data in readily processed
representations.
SPI
SPI is a programmatic interface designed to facilitate management of subsystems
without operator intervention:
•
Programmers do not need to be concerned with the internals of message format
but can concentrate instead on requesting and retrieving relevant data.
•
Subsystems can add features without changing the basic interface—existing
applications interact successfully with new versions of subsystems.
•
A programmer who uses the interface in one programming language to
communicate with one subsystem then knows most of what is necessary to use
the interface in other languages and with other subsystems.
•
Application programs can use any interprocess communication features (such as
nowait or waited I/O) that are available in the language in which they are written.
SPI consists of:
Topic Page
The Components of SPI
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The Environment for D-Series RVUs 1-10