[OS] Computer System Architecture : Processors

• Types of Computer System based on number of General Purpose Processors

  1. Single Processor Systems

  2. Multiprocessor Systems

  3. Clustered Systems

 

1. Single Processor Systems

• One main CPU capable of executing a general purpose instruction set including instructions from user processes.

• Other special purpose processors are also present which perform device specific tasks

  "Sepecial purpose processors" like Convert typing a keyboard to code by microprocessors.

→ 여기서 Single Processor은 a general purpose processors만 의미한다.

 

 

2. Multiprocessors Systems

• Also known as parrallel systems or tightly coupled systems

• Has two or more processors in close communication(also syncronization), sharing the computer bus and sometimes the clock, memory, and peripheral(주변) devices

  → Multiprocessors which are closely communicating with each other because they need to work together to perform certain tasks(single tasks or different tasks depending on the kind of system)

• Advatages:

  • Increased throughput

    → multiple processors have more increased throughput & performance than single

  • Economy of scale

    → Sharing resource(multiple) > individual resource(single)

  • Increased reliability

    → When one of processor is failed, multiple processors is more reliable than single

Symmetric Multiprocessing(SMP)

two or more identical processors are connected to a single, shared main memory, have full access to all input and output devices, and are controlled by a single operating system instance that treats all processors equally, reserving none for special purposes.

Asymmetric Multiprocessing

Asymmetric Multiprocessing system is a multiprocessor computer system where not all of the multiple interconnected central processing units (CPUs) are treated equally. In asymmetric multiprocessing, only a master processor runs the tasks of the operating system.

 

 

3. Cluster Systems

• Like multiprocessor systems, clustered systems gather together multiple CPUs to accomplish computational work

• What are differences "multiprocessors" and "Cluster"

  • "Cluster" Systems are composed of two or more individual systems coupled together.
  • "Multiprocessors" Systems are composed of two or more processors.

• Provides high availability

• Can be structured asymmetrically or symmetrically

   

  "Asymmetrically"

  • One machine in Hot-Standby mode
  • Others run applications

  "Symmetrically"

  • Two or more hosts run applications
  • Monitors each other

 

Ref

1. Symmetric Processor (Wiki)
2. Differecne between Asymmetric and Symmetric Multiprocessing

 

 

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