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This is where the computer stores its operating system and application software, as well as user documents such as text files, spreadsheets or graphics files. The hard disk is the only component inside
the computer where data can be retained when the computer is switched off. Three key values are used to define the quality of a hard disk drive: |
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- Capacity
- Speed:
- Average seek time: time taken to position the data heads for a randomly located request.
- Seek time: average time taken by the head to travel between any two tracks.
- Rotational speed: When the data head is finally positioned over the correct track, the speed at which the platter is rotating determines how long it takes before the required sector arrives at the data head, in order for the read or write operation to be performed.
- Reliability is measured by the Mean Time Between Failure (hours)
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