The code for these two routines is also shown in

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Unformatted text preview: own performance measurement code. We hope that our case study will help you in this task. We summarize our findings in the form of a protocol that can guide your experiments. 9.1 The Flow of Time on a Computer System Computers operate on two fundamentally different time scales. At a microscopic level, they execute instructions at a rate of one or more per clock cycle, where each clock cycle requires only around one nanosecond (abbreviated “ns”), or ½¼ seconds. On a macroscopic scale, the processor must respond to external events 9.1. THE FLOW OF TIME ON A COMPUTER SYSTEM 451 that occur on time scales measured in milliseconds (abbreviated “ms”), or ½¼ ¿ seconds. For example, during video playback, the graphics display for most computers must be refreshed every 33 ms. A worldrecord typist can only type keystrokes at a rate of around one every 50 milliseconds. Disks typically require around 10 ms to initiate a disk transfer. The processor continually switches between these many tasks on a macroscopic time scale...
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