Tunable Kernel Parameters

Interprocess Communication (IPC) Subsystem
System V Interprocess Communication Mechanisms
Chapter 5
34
System V Interprocess Communication Mechanisms
The HP-UX operating system uses shared memory to provide three mechanisms for
communicating between cooperating programs and processes:
Messages Message data is stored in a given part of shared memory to be
retrieved by receiving programs. For more information about how
shared memory space for messages is allocated and managed, see
“Overview of Message Queue Operations” on page 35.
Semaphores Shared storage locations that contain up/down counters for signaling
the current status of cooperating processes. For more information
about how shared memory space for semaphores is allocated and
managed, see “Overview of Semaphore Operations” on page 37.
Shared Memory Reserved data storage area shared by two or more processes by means
of identically-defined data structures in each cooperating process. For
more information about how shared memory space for shared data
structures is allocated and managed, see “Overview of Shared Memory
Operation” on page 38.