Multi-processor: Difference between revisions

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A '''multi-processor''' is a system with more than one [[Central Processing Unit|CPU]]. There are a tremendous range of designs, from 'tightly-coupled' (where they share access to some [[main memory]]) onward. Another axis for dividing them is among:
A '''multi-processor''' is a system with more than one [[Central Processing Unit|CPU]]. There are a tremendous range of designs, from 'tightly-coupled' (where they share access to some [[main memory]], which usually has to be [[multi-port memory]]), onward.
 
Another axis for dividing them is among:


* MIMD - 'multiple instruction streams, multiple data sets'
* MIMD - 'multiple instruction streams, multiple data sets'
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In the latter, each CPU is fed different data, but they all execute the same [[instruction]]s in the same order.
In the latter, each CPU is fed different data, but they all execute the same [[instruction]]s in the same order.


Among tightly-coupled systems, one can distinguish between 'symmetric' and 'asymmetric' systems; in the former, all the CPUs are 'equal', and can e.g. field [[interrupt]]s from any device. The latter are often so-called 'master/slave' systems, with one CPU in each class.
Among tightly-coupled systems, one can distinguish between 'symmetric' and 'asymmetric' systems. In the former, all the CPUs are 'equal', and no CPU has a special, distinguished role (so often any CPU can e.g. field [[interrupt]]s from any [[peripheral]]). The latter are often so-called 'master/slave' systems, with one CPU in the first class, and one or more in the second.


With the advent of very-high-speed [[local area network|LANs]], it is now common to create multi-processors by simply linking togather a number of ordinary systems with such a network.
With the advent of very-high-speed [[local area network|LANs]], it is now common to create multi-processors by simply linking together a number of ordinary systems by use of such a network.


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Revision as of 19:19, 19 August 2018

A multi-processor is a system with more than one CPU. There are a tremendous range of designs, from 'tightly-coupled' (where they share access to some main memory, which usually has to be multi-port memory), onward.

Another axis for dividing them is among:

  • MIMD - 'multiple instruction streams, multiple data sets'
  • SIMD - 'single instruction streams, multiple data sets'

In the latter, each CPU is fed different data, but they all execute the same instructions in the same order.

Among tightly-coupled systems, one can distinguish between 'symmetric' and 'asymmetric' systems. In the former, all the CPUs are 'equal', and no CPU has a special, distinguished role (so often any CPU can e.g. field interrupts from any peripheral). The latter are often so-called 'master/slave' systems, with one CPU in the first class, and one or more in the second.

With the advent of very-high-speed LANs, it is now common to create multi-processors by simply linking together a number of ordinary systems by use of such a network.