Research Article
A Stochastic Analysis of Hard Disk Drives
Table 1
The symbols used in our mathematical model and derivation.
| | Radius of the innermost track | | Radius of the outermost track | | The speed of the read/write head | | In C-SCAN, the time to backtrack from the outer to the inner track | | Arrival rate of the requests | | r.v. denoting radius of the track specified by a memory request | | pdf for | | r.v. denoting job size; rotational latency + transfer time for a request | | pdf for | | The (large) number of jobs in a hypothetical request sequence | | The average access time of a job | | The time access time of label | | The part of during which the head is moving | | The part of during which the head is processing a job | | r.v. denoting the number of jobs in the system not being processed at a random time | | The load of the system | | r.v. denoting the remaining time on a job being processed | | The pdf of the location of the head, given that it is not backtracking |
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