Online Computer Dictionary

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Queried for: scan  About scan

Definition:
1. (computer peripheral) See scanner. 2. (circuit design) See scan design. 3. (functional programming) See scanl, scanr. 4. An algorithm for scheduling multiple accesses to a disk. A number of requests are ordered according to the data's position on the storage device. This reduces the disk arm movement to one "scan" or sweep across the whole disk in the worst case. The serivce time can be estimated from the disk's track-to-track seek time, maximum seek time (one scan), and maximum rotational latency. Scan-EDF is a variation on this.