The Free Online Dictionary of Computing (http://foldoc.doc.ic.ac.uk/) is edited by Denis Howe <dbh@doc.ic.ac.uk>.

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Scan-EDF

<storage, algorithm> A variation of the Scan disk aceess algorithm for use in a real-time environment where, in general, requests are served according to Earliest Deadline First. If two requests share the same deadline, they may be reorganised according to Scan.

A typical example is a video server that retrieves video data from a hard disk. The playback of a video impose tight real-time constraints but if the server retrieves data once every second for each video channel, Scan-EDF can be applied, reducing the seek overhead.

(1995-11-15)