access time

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access time

Computing the time required to retrieve a piece of stored information

access time

[′ak·ses ‚tīm]
(computer science)
The time period required for reading out of or writing into the computer memory.

access time

(hardware, storage)
The average time interval between a storage peripheral (usually a disk drive or semiconductor memory) receiving a request to read or write a certain location and returning the value read or completing the write.

access time

(1) Memory access time is how long it takes for a character in memory to be transferred to or from the CPU. In a PC or Mac, fast RAM chips have an access time of 70 nanoseconds (ns) or less. SDRAM chips have a burst mode that obtains the second and subsequent characters in 10 ns or less.

(2) Disk access time is an average of the time between initiating a request and obtaining the first data character. It includes the command processing, the average seek time (moving the read/write head to the required track) and the average latency (rotation of disk to the required sector). This specification must be given as an average, because seek times and latency can vary depending on the current position of the head and platter.

Fast hard disks have access times of 10 milliseconds (ms) or less. This is a common speed measurement, but overall disk performance is significantly influenced by channel speed (transfer rate), interleaving and caching. See cache, seek time and latency.
References in periodicals archive ?
The NW601-30's architecture was optimized not only at the micro level, but also at the macro level, taking into account such factors as host latency, PCI-bus arbitration, and disk access time.
The chip's architecture is optimized at both the micro and macro level, taking into account host latency, PCI-bus arbitration, and disk access time, among other factors.