Access Time
Hard Drive Recovery - Access Time
Access Time is the time delay between a communication request to an electronic system and the access to it. Access time is measured only on access attempts that yield successful results.
In telecommunications system, access time refers to the time period between the start of an access attempt and the successful access. In computer, it is the time period between an instant at which an instruction control unit initiates a communication to call for data or make a request to store data and the instant at which the data is delivered or the storage process is started.
Access time, in disk drives, is the time required for a computer to process the data from the processing unit and then retrieve the required data from the storage devices, including hard disks. For hard disks, the access time comprises the sum of the spin-up time, seek time, rotational delay and transfer time.
Spin-up time refers to the time required to accelerate the disk to the desired operating speed. Drives, which are frequently used, are allowed to spin continuously to improve access time, but it would result in higher energy consumption and noise.
Seek time, in computing, refers to the time required by the access arm to reach the desired disk track.
Rotational delay refers to the delay in the rotation of the disk to bring the required sector in the disk under the read/write mechanism. Rotational delay depends on rotational speed of a disk, and it is measured in revolutions per minute (RPM).
Transfer time refers to the time during which data is actually read or written to a medium with a certain throughput.
