In computer storage, direct access is the ability to obtain data from a storage device by going directly to where it is physically located on the device rather than by having to sequentially look for the data at one physical location after another. A direct access storage device (DASD) has the electrical or electromechanical means to be immediately positioned for reading and writing at any addressable location on the device.
An alternative to direct access is sequential access, in which a data location is found by starting at one place and seeking through every successive location until the data is found. Historically, tape storage is associated with sequential access, and disk storage is associated with direct access.
This was last updated in May 2001