Message passing ( in computer science)

Message passing ( in computer science)

• 2.
  INTER-PROCESS COMMUNICATION • Whenmessages are passed between two different processes we speak of inter-process communication. • Message is a block of information. • Communication may be of two types. 1. Message passing. 2. Shared memory.
• 3.
  MESSAGE PASSING • Messagepassing is a paradiagram of communication where messages are sent from a sender to one or more recipent. OR • Message passing refers to mean of communication between: 1. Different threads within a process. 2. Different processes running on same node. 3. Different processes running on different node.
• 4.
  • MESSAGE hasa predefined structure. • Message passing uses two system calls: 1. Send(name of destination process, message); 2. Receive(name of source process , message);
• 5.
  MESSAGE PASSING COMMUNICTION Mesaagepassing communication may be of two types. 1. Direct communication: Explicitly name the process you are communicating with. 2. Indirect comunication: communicate using mailboxes owned by receiver.
• 6.
  DIRECT COMMUNICATION INDIRECT COMMUNICATION
• 7.
  Message passing usestwo system calls. Send(B, message); Receive(A, message); A B DIRECT COMMUNICATION Symmetric addressing: Send(B,msg ) Receive(A,msg)
• 8.
  DIRECT COMMUNICATION Asymmetric addressing: AB Message passing uses 2 system call: Send(B, message) Receive( message) Send(B,Msg) Receive(msg)
• 9.
  INDIRECT COMMUNICATION INDIRECT COMMUNICATIONMAIL BOX
• 10.
  1. Synchronous messagepassing: requires the sender and receiver to wait for each other to transfer the message. • Blocking send. • Blocking receive. 1. Asynchronous message passing: delivers a message from sender to receiver, without waiting for a receiver to be ready. • Non blocking send . • Non blocking receive.
• 11.
  SYNCHRONOUS MESSAGE PASSING BLOCKINGSEND door Waiting busy msg
• 12.
  SYNCHRONOUS MESSAGE PASSING Blockingreceive door Busy waiting
• 13.
  ASYNCHORON0US MESSAGE PASSING Non-blockingsend msg msg MAIL BOX
• 14.
  NON-blocking receive msg MAIL BOX door Zzzzzz
• 15.
  THE FOLLOWING TYPESOF COMMUNICATION LINK ARE POSSIBLE THROUGH MAILBOX • One-to-one link • Many-to-one link • One-to-many link • Many-to-many link