The time taken to find and retrieve a particular piece of data from memory or a hard disk. Memory chips have an access time of around 100 nanoseconds (ns). However, access time is normally used for hard disks as a way of giving some idea of the hard disk's performance. With hard disks, the average access time is often quoted. Measured in thousandths of a second (ms), this is the time it typically takes for the drive to get to a part or sector of the disk after the computer has requested that particular sector.
