Inter-process communication(IPC)

Inter-process communication

In computing, Inter-process communication (IPC) is a set of methods for the exchange of data among multiple threads in one or more processes.
Processes may be running on one or more computers connected by a network
IPC methods are divided into methods for message passing, synchronization, shared memory, and remote procedure calls (RPC).

http://en.wikipedia.org/wiki/Inter-process_communication




Processes executing concurrently in the OS may be either independent processes or cooperating processes.

Cooperating processes require an interprocess communication (IPC) mechanism that will allow them to exchange data and information.

inter-process communication, which is most commonly one of two types: Shared Memory systems or Message Passing systems

There are two fundamental models of interprocess communication:

Shared Memory. A region of memory that is shared by cooperating processes is established. Processes can then exchange information by reading and writing data to the shared region.

Message Passing. Communication takes place by means of messages exchanged between the cooperating processes


Shared Memory is faster once it is set up, because no system calls are required and access occurs at normal memory speeds.
However it is more complicated to set up, and doesn't work as well across multiple computers.
Shared memory is generally preferable when large amounts of information must be shared quickly on the same computer.
Shared memory allows maximum speed and convenience of communication, as it can be done at memory speeds when within a computer.
Shared memory is faster than message passing, as message-passing systems are typically implemented using system calls and thus require the more time-consuming task of kernel intervention

Message Passing requires system calls for every message transfer, and is therefore slower, but it is simpler to set up and works well across multiple computers. Message passing is generally preferable when the amount and/or frequency of data transfers is small, or when multiple computers are involved.
Message passing is useful for exchanging smaller amounts of data, because no conflicts need be avoided





3.5 Examples of IPC Systems

3.5.1 An Example: POSIX Shared Memory
3.5.2 An Example: Mach
3.5.3 An Example: Windows XP



http://siber.cankaya.edu.tr/ozdogan/OperatingSystems/ceng328/node96.html
http://www.cs.uic.edu/~jbell/CourseNotes/OperatingSystems/3_Processes.html