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Special Forums Hardware Filesystems, Disks and Memory semaphores and shared memory Post 22688 by Perderabo on Saturday 8th of June 2002 01:50:06 PM
Old 06-08-2002
These are two types IPC facilities. IPC (Inter Process Communication) allows two or more processes to talk with one another. They both require space in kernel tables if they are to be successfully allocated. That's where the SysAdmin comes in. He or she must ensure that there is room for all the IPC's that the system needs.

One example is a relational database management system such as Oracle or Sybase. A RDBMS might have one server program that actually talks to the disk drives. And it would have multiple client programs that need to use the database. The programs communicate via IPC's. And when you install Oracle or Sybase, one of the steps is to review the kernel IPC parameters. They usually will need to be increased.
 

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IPC(2)							     Linux Programmer's Manual							    IPC(2)

NAME
ipc - System V IPC system calls SYNOPSIS
int ipc(unsigned int call, int first, int second, int third, void *ptr, long fifth); DESCRIPTION
ipc() is a common kernel entry point for the System V IPC calls for messages, semaphores, and shared memory. call determines which IPC function to invoke; the other arguments are passed through to the appropriate call. User programs should call the appropriate functions by their usual names. Only standard library implementors and kernel hackers need to know about ipc(). CONFORMING TO
ipc() is Linux-specific, and should not be used in programs intended to be portable. NOTES
On some architectures--for example x86-64 and ARM--there is no ipc() system call; instead msgctl(2), semctl(2), shmctl(2), and so on really are implemented as separate system calls. SEE ALSO
msgctl(2), msgget(2), msgrcv(2), msgsnd(2), semctl(2), semget(2), semop(2), semtimedop(2), shmat(2), shmctl(2), shmdt(2), shmget(2) COLOPHON
This page is part of release 3.53 of the Linux man-pages project. A description of the project, and information about reporting bugs, can be found at http://www.kernel.org/doc/man-pages/. Linux 2012-10-16 IPC(2)
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