Mailing the story:
Using Shared Memory from PHP
IPC is one of the most important features of the UNIX systems. It allows two processes to communicate with each other. In this article we'll work with two System V IPC functions, semaphores and shared memory. System V IPC originated in SVR2, but has implementations by numerous vendors. It's also available in SVR4. This article introduces shared memory and synchronization (semaphores).