CS452 - Real-Time Programming - Fall 2008

Lecture 27 - Occam 2


Questions & Comments

  1. Coyotos

Hardware

Fourth Generation

  1. Multi-(multi-core CPUs) called servers
  2. Multi-core microprocessors
  3. Stream processors

The Transputer: a Second Generation Offsoot

Use many co-operating, medium capability microCPUs to do a big job.

Problem is communication

Comminication requires either

The transputer was an early, now vanished, example of the latter


Occam 2

Basic idea

  1. processes (tasks)
  2. channels
  3. time

Combining processes

  1. sequential
  2. conditional
  3. looping
  4. parallel
  5. alternation

Channels

  1. input
    channel ? variable
  2. output
    channel ! value // the value of a variable or the result of an procedure
  3. input & output provide synchronization

Time

The Result

You can write a type-safe server, BUT

Program structure is more static than is allowed in your system.


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