Processes with communication exclusive from the OS

Question

Most OSes use the message passing system to let 2 processes communicated with each other.This works by a shared mailbox between the OS and each process loaded in the RAM however are there processes which have their own shared mailbox and can communicate without the OS acting as a middleman?

Answer 1

Two isolated processes need some OS support for passing messages between each other, but there need not be a system call for every message.

One simple way is to use virtual memory. You could, for example, use shared memory or a memory-mapped file to share a piece of memory between two processes, and communication can then proceed using shared data structures for communication.

Many operating systems also provide cross-process synchronisation objects if waiting is needed.