Unix ipc Mechanism 0th

Unix ipc Mechanism 0th

Two UNIX standards: 1. POSIX is a standard developed by IEEE (Institute for Electrical and Electronic Engineers) and is currently maintained by ISO/IEC. The POSIX standard consists of three parts: Part1 and Part2, known as posix.1 and posix.2, respectively.

• System API for C Language
• Shell and Utility
• System Administration (in preparation ...)

2. x/o p e n is an international computer manufacturer organization. It proposes a 7-volume portability guide x/Open portabilityguide (x/o p e n portability guide) version 3rd (x/Open 1989 〕, we call it x p g 3. Later, the release of "X/open single UNIX specification" was called unix95. 1997 again, unix98 was released. In addition System V, Also known At&t System VIs one of the many versions of the UNIX operating system, and the other is BSD. It was initially developed by at&t and released for the first time in 1983. A total of four major versions of System V are released: versions 1, 2, 3, and 4. System V Release 4, or svr4, is the most successful version and becomes the source of Common Unix features. S Ystem V's IPC is required by open group's single UNIX Specification Version 2 [UNIX 98. Therefore, posix ipc and System v ipc are described in the book of UNIX inter-process communication.
POSIX and System V Support different messagequeue, shared memory, and semaphores. Pipes, FIFO, and record locking mechanisms are neither POSIX nor xpg standards.

Message transmission
Messagequeues	Including POSIX messagequeue and systemv messagequeue
Pipe, FIFO

Synchronization Mechanism
Mutex, condition Variables
Read-write locks
Record locking
Semaphores
Shared Memory	Including POSIX semaphores and systemv semaphores
Shared Memory	Including POSIX sharememory and systemvmemory
Others
Doors and SunRPC

Linux IPC:

At first, Unix was developed into two branches: System V (system IPC) and BSD (socket IPC ). Linux integrates the IPC Mechanism of both. And implements posix ipc. For more information, see:Profound Understanding of Linux inter-process communication (IPC)