Access time
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Access time is the time delay or latency between a request for access to an electronic system, and the access being granted or the requested data returned.
- In a telecommunications system, access time is the delay between the start of an access attempt and successful access. Access time values are measured only on access attempts that result in successful access.
- In a computer, it is the time interval between the instant at which an instruction control unit initiates a call for data or a request to store data, and the instant at which delivery of the data is completed or the storage is started.
- In magnetic disk drives, it is the time for the access arm to reach the desired track and the delay for the rotation of the disk to bring the required sector under the read-write mechanism. Average values for the rotational latency are as follows:
| Spindle RPM | Average Latency (ms) |
|---|---|
| 4200 | 7.14 |
| 5400 | 5.55 |
| 7200 | 4.17 |
| 10000 | 3 |
| 15000 | 2 |
- This article contains material from the Federal Standard 1037C (in support of MIL-STD-188), which, as a work of the United States Government, is in the public domain.
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