Actually, if you fork() a process, the memory pages of the new process are shared with the old, using copy-on-write access rules. Obviously, that doesn't enable

Actually, if you fork() a process, the memory pages of the new process are shared with the old, using copy-on-write access rules. Obviously, that doesn't enable any kind of communication, but can be damn handy if you need a read-only chunk of memory that is initialised once but needs to be shared with all processes involved.