In most
operating systems each
process runs in
its own
protected memory space; this means that a process cannot
access the memory used by another process (this would cause a lot of
problems with both system
stability and data
integrity). However,
it is often useful
and/or neccessary to be able to let processes
communicate with each other in a
controlled manner. This is called
inter-process communcation or
IPC.
The methods of IPC vary, but the following are the ones usually
referred to as System V IPC:
Two other common techiques are