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REVIEW Chap1

:material-circle-edit-outline: 约 223 个字 :material-clock-time-two-outline: 预计阅读时间 1 分钟

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Computer abstractions and Technology

ISA: Instruction set architecture

*What is a Computer？

  • Computer is
    • an electronic device
    • that manipulates data
    • according to a list of instructions (program),
    • with capability of a Turing machine.
  1. Electronic realization
  2. A set of instructions in a well-defined manner --> general-purpose
  3. Execution of a pre-recorded list of instructions --> program-controlled
  4. Memory that can store instructions and data --> stores program
  5. Turing-complete in theory --> equivalent to Turing machine

Computer design: performance and idea

  • response time / execution time
  • throughput / bandwidth
    • total work per unit time

performance = \(\frac{1}{execution\, time}\)

  • Elapsed time: total response time in all aspects
  • CPU time: without I/O time and other aspects
    • CPU time has two ways to calculate
      • Clock Cycle / Clock Rate
      • Instruction Count x CPI
  • CPI: Cycles per Instruction
  • Clock Rate: 即每个周期的运行速度
    • cycle类比s，rate类比v，time即t
    • cycle time即单位路程使用的时间，与s相乘可得t，是v的反比
\[ CPU\, Time=(CPU)\, Clock \,Cycles \times Clock\, Cycle\, Time\\=\frac{(CPU)\, Clock \,Cycles}{Clock\,Rate} \]
\[ Clock\,Rate = \frac{1}{Clock\, Cycle\, Time}=\frac{Clock \,Cycles}{CPU\, Time} \]
\[ Clock\,Cycles = Instruction\,Count \times CPI \]
\[ CPU\,Time=Instruction \,Count\times CPI\times Clock\,Cycle\,Time\\=\frac{Instruction \,Count\times CPI}{Clock\,Rate} \]