1. Geometry either portion of a circle included between two radii and an arc. Area: ½r2θ, where r is the radius and θ is the central angle subtended by the arc (in radians)
2. a measuring instrument consisting of two graduated arms hinged at one end
3. Computing the smallest addressable portion of the track on a magnetic tape, disk, or drum store
Collins Discovery Encyclopedia, 1st edition © HarperCollins Publishers 2005
The following article is from The Great Soviet Encyclopedia (1979). It might be outdated or ideologically biased.
(1) A sector in the plane is a region bounded by two rays issuing from an interior point of a figure and by an arc of its boundary cut off by these rays. In particular, a sector of a circle is bounded by two radii and an arc cut off by the radii. The area of a sector of a circle is equal to lr/2 or πr2α /360, where l is the length of the arc, α is the central angle (in degrees) subtended by the arc, and r is the radius of the circle.
(2) A sector in space is the part of a solid bounded by a conical surface whose vertex is in the solid and by the part of the solid’s surface cut off by the conical surface. A spherical sector is an example of a sector in space.
The Great Soviet Encyclopedia, 3rd Edition (1970-1979). © 2010 The Gale Group, Inc. All rights reserved.
A portion of a track on a magnetic disk or a band on a magnetic drum.
A unit of data stored in such a portion.
A clearly defined area or airspace designated for a particular purpose.
Coverage of a radar as measured in azimuth.
A portion of a circle bounded by two radii and an arc joining their end points.
Something resembling the sector of a circle, as a warm sector between the warm and cold fronts of a cyclone.
McGraw-Hill Dictionary of Scientific & Technical Terms, 6E, Copyright © 2003 by The McGraw-Hill Companies, Inc.
sectorThe smallest unit of data that is written to and read from a storage drive. The initial hard disk sector sizes were 128 and 256 bytes long but were later increased to 512. Eventually, sectors were enlarged to the "Advanced Format" size of 4,096 bytes. See cluster, sector interleave and magnetic disk.
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