Interprocess Communication

• The exit status of a child process. That is the simplest form of communication between two processes.
• Interprocess communication (IPC) is the transfer of data among processes.
• We discuss five types of interprocess communication:
  1. Shared memory permits processes to communicate by simply reading and writing to a specified memory location.
  2. Mapped memory is similar to shared memory, except that it is associated with a file in the filesystem.
  3. Pipes permit sequential communication from one process to a related process.
  4. FIFOs are similar to pipes, except that unrelated processes can communicate because the pipe is given a name in the filesystem.
  5. Sockets support communication between unrelated processes even on different computers.
• These types of IPC differ by the following criteria:
  • Whether they restrict communication
    • to related processes,
    • to unrelated processes sharing the same filesystem,
    • to any computer connected to a network.
  • Whether a communicating process is limited
    • to only write data,
    • to only read data.
  • The number of processes permitted to communicate.
  • Whether the communicating processes are synchronized by the IPC for example, a reading process halts until data is available to read.