Inter-Process Communications (IPC)

in Distributed Systems (or Parallel Progs)

Some Terminology

• processes vs. threads
  A process consists of:

  • in-memory copy of the machine code
  • memory area (block of virtual memory) containing variables — stack and heap
  • values that the OS cares about (e.g., open files, process owner & permissions)
  • process state/context: register values, physical memory addressing
•  
• distributed systems vs. parallel programs
• running concurrently (both)
• using shared resources
     OR working together in some way,
     OR some combination of the above (both)

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lack of global clock vs. shared clock
independent failure of components vs. not
(usually) separate local memory vs. shared memory
communication: message passing vs. message passing or shared memory
(inter-process communication, or IPC)