average seek timeThe mean time it takes to move the {head} of a {disk drive} from one {track} to another, averaged over the source and destination cylinders. The average seek time gives a good measure of the speed of the drive in a multi-user environment where successive read/write request are largely uncorrelated. Ten ms is common for a {hard disk} and 200 ms for an eight-speed {CD-ROM}. (1997-07-22)