NonStop S-Series Server Description Manual (G06.24+)

HP NonStop S-Series Server Description Manual—520331-003
9-1
9 Interprocessor Communication
This section describes the hardware, software, and operating sequences by which
processors in NonStop S-series servers communicate with each other. Such
communication is termed interprocessor communication (IPC) and is achieved by
the exchange of messages between processes.
To provide transparency as to whether two communicating processes are in the same
or different processors, all message traffic is managed by the message system. The
message system uses the IPC mechanisms described in this section when the two
processes reside in different processors. The message system itself, which consists of
a library of message-system procedures and driver procedures that are part of the
NonStop Kernel operating system, is not extensively described in this section or this
manual.
Before reading this section, you should have read Section 2, Principles of System
Operation, for a basic understanding of ServerNet transactions and ServerNet packets.
ServerNet transactions (request and response) form the basis for all communication
through the ServerNet fabrics.
The topics covered in this section are:
Interprocessor Protocols
Linker-Listener Protocol
Message System Protocol
Message Transfer Mechanisms
Message Transfer Methods
Request With Short Request Data
Request With Medium Request Data
Request With Long Request Data
Reply and Reply Acknowledge