Operating system
- 1. INTERPROCESS COMMUNICATION IN OS By, S.Subhalakshmi, M.Sc(cs), Nadar saraswathi college of arts and science,theni.
- 2. INTER PROCESSOR COMMUNICATION: Inter processor communication in a multiprocessor system. It is used to generate information about certain sets of computations finishing on one processor and to let the other processors. They waiting for finishing the computations take note of the information. Any process that does not share data with any other process is independent.
- 3. There are several reason for providing an environment that allows process cooperation: INFORMATION SHARING: Traditional information sharing referred to one-to-one exchanges of data between a sender and receiver. COMPUTATION SPEEDUP: The parallel run time is defined as the time that elapses from the moment that a parallel computation.
- 4. MODULARITY: Modularity refers to the concept of making multiple modules first and then linking and combining them to complete system. CONVENIENCE: Even an individual user may work on many tasks at the same time. For instance, a user may be editing, printing, and compiling in parallel.
- 6. SHARED MEMORY SYSTEM: Shared memory is memory that may be simultaneously accessed by multiple programs with an intent to provide communication among them or avoid redundant copies. Interprocess communication using shared memory requires communicating processes to establish a region of shared memory. Other process that wish to communicate using this shared memory segment must attach it to their address space.
- 7. MESSAGE PASSING SYSTEMS: Message passing provides a mechanism to allow processes to communicate and to synchronize their actions without sharing the same address space. A message passing facility provides at least two operations: 1.send(message) 2.receive(message)
- 8. Messages sent by a process can be either fixed or variable size. If only fixed-sized messages can be sent, the system-level implementation is straightforward. Here are several methods for logically implementing a link and the send() / receive() option. Direct and indirect communication Synchronous or asynchronous communication Automatic or explicit buffering.
- 9. NAMING: Under direct communication, each process that wants to communicate must explicity name the recipient or sender of the communication. With indirect communication, the messages are sent to and received from mailboxes, or ports. The operating system then must provide a mechanism that allows a process to do the following:
- 10. Create a new mailbox. Send and receive messages through the mailbox. Delete a mailbox. SYNCHRONIZATION: Communication between processes take place through calls to send() and receive() primitives. Message passing may be either blocking and unblocking also known as synchronous and asynchronous.
- 11. BUFFERING: Whether communication is direct or indirect, messages exchanged by communicating processes reside in a temporary queue. Basically such queues can be implemented in three ways: ZERO CAPACITY: The queue has a maximum length of zero; thus, the link cannot have any messages waiting in it.
- 12. BOUNDED CAPACITY: If the queue is not full when a new message is sent, the message is placed in the queue and the sender can continue execution without waiting. UNBOUNDED CAPACITY: The queues length is potentially infinite; thus, any number of messages can wait in it. The sender never blocks.