1. In a telecommunication system, the elapsed time between the start of an access attempt and successful access.
Note: Access time values are measured only on access attempts that result in successful access.
2. In a computer, the time interval between the instant at which an instruction control unit initiates a call for data and the instant at which delivery of the data is completed.
3. The time interval between the instant at which storage of data is requested and the instant at which storage is started.
4. In magnetic disk devices, 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.
Source: from Federal Standard 1037C and from MIL-STD-188