---

Introduction to Interconnection Networks

---

• MIMD Parallel Computers
  • A MIMD computer fetches multiple instructions at the same time and execute multiple instructions at the same time

  • There are 2 common MIMD architectures:
    1. Shared Memory MIMD:

       NOTE: The memory is split into multiple banks to allow simultaneous transfers of values

       Values stored in different memory banks can be transfered from/to CPUs simultaneously

       ---

    2. Message Passing MIMD:

       ---

       Notice that in both architectures, the "components" are interconnected by a interconnection network

  ---

  ---

• Differences between Shared-Memory MIMD and Message-Passing MIMD
  • Notice that:
    • The inter-connection networks of the shared-memory MIMD computer connects a CPU to a memory module or a memory module to a CPU

    • The inter-connection networks of the message-passing MIMD computer connects two different SISD computers

  • As a result:
    • The data transfered in shared-memory MIMD computer is:
      • a memory address from a CPU to a memory module or
      • a word (stored in memory) from a memory module to a CPU

      The amount of data transfer is fixed size

    • The data transfered in Message-passing MIMD computer is:
      • a message from a computer to another computer

      The amount of data transfer is variable size

    ---

  • The fixed size messages in shared-memory MIMD and variable size messages in message-passing MIMD lead to different ways to solutions of inter-connection networks to these computers.