- Access time
Access time is the time delay or latency between a request to an electronic system, and the access being completed or the requested data returned.
* In a
telecommunications system, access time is the delay between the start of an access attemptand 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 dataor a request to store data, and the instant at which delivery of the data is completed or the storage is started.
disk drives, disk access time is the time required for a computer to process data from the processor and then retrieve the required data from a storage device, such as a hard drive. For hard drives, disk access time is determined by a sum of the spin-up time, seek time, rotational delay and transfer time.
Spin-uptime - is the time required to accelerate the disk to operating speed. Frequently used drives are often left spinning to improve access time, but drives may be spun down to reduce energy use or noise.
Seek time- is the time for the access arm to reach the desired disk track.
Rotational delay- the delay for the rotation of the disk to bring the required disk sectorunder the read-write mechanism. It greatly depends on rotational speed of a disk, measured in revolutions per minute(RPM).
** Transfer time - time during which data is actually read or written to medium, with a certain
Theoretical averages of the access time or "latency" are shown in the table below, based on the empirical relation that the average latency in milliseconds for such a drive is about 30000/RPM:
Seek Time : It is the amount of time between when the CPU requests a file and when the first byte of the file is sent to CPU. Times between 10 to 20 milliseconds are common.:
Comparison of latency and bandwidth
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Look at other dictionaries:
access time — access times N COUNT Access time is the time that is needed to get information that is stored in a computer. [COMPUTING] This system helps speed up access times … English dictionary
access time — access .time n [U and C] technical the time taken by a computer to find and use a piece of information in its memory … Dictionary of contemporary English
access time — access ,time noun uncount COMPUTING the time it takes for a computer program to find a piece of information and make it available … Usage of the words and phrases in modern English
access time — ☆ access time n. the length of time required by a computer to retrieve or store data … English World dictionary
Access Time — [engl.], Zugriffszeit … Universal-Lexikon
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