Buses and types of computer.

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Buses and types of computer.

• Paul Strickland

Liverpool John Moores University
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Introduction

• Bus Architecture
• Types of Computers

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Data Bus

• May be 8-, 16-, 32-, ... bits.
• Carrying 1, 2, 4, ... bytes of data at one time.
• How many bytes could a 24-bit data bus carry?
• What sort of data bus could carry 8 bytes at once?

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Address Bus

• May be 8-, 16-, 32-, ... bits.
• Unsigned binary value gives address in RAM.
• 32 bits 2 10 10 10.
• Address 4 1024 1024 1024 bytes 4
  gigabytes.
• What about 8, 16 and 24-bit address buses?

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Speed

• Most computers measure clock speed in MHz or GHz.
• These really mean 1 million or 1 billion
  instructions per second.
• Super computers use FLOPS Floating Point
  Oerations Per Second.
• e.g. 1000.345 - 0.000345 would take you longer
  than 3 - 2!

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Palm top

• up to 64Mb RAM
• No disc (need to connect to another computer)
• 256MHz processor

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Personal computers

• Up to 4Gb RAM
• 100 Gb Hard disk
• 1GHz processor

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High Performance Systems

• Several processors in parallel, with Gb of RAM on
  each.
• several Tb (1024 Gb) of storage available.
• Up to 1000 G-FLOPS (Peta flops) speed.

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Homework

• Find an example of each of the 3 types. How?
• do a web search on High Performance Systems
• go in a computer shop.
• visit an online computer dealer e.g. Amazon
• read a computer magazine.
• Find out the amount of RAM, disk size and clock
  speed for each.