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(1) A unit of a mechanism in the form of a wheel with a groove around its circumference over which a cable or chain is drawn. It is used to change the direction of a tractive force and to obtain a force or velocity advantage; more rarely, to transfer a torque. Depending on their function, blocks are known as guide, balance, runner, and driving (for imparting rotary motion to a shaft) pulleys. In order to achieve a large force or velocity advantage, a lifting mechanism made up of a combination of blocks (a block and tackle) is used.
(2) A subassembly of a machine, consisting of several identical parts, such as a block of cylinders in an internal combustion engine or the spindle block in a multiple-spindle machine.
(3) A stone (concrete or ceramic) of large size (appreciably larger than a brick) used in the construction of buildings and for road surfacing.
N. IA. NIBERG
block(1) A group of disk or tape records that is stored and transferred as a single unit. On a CD, a block consists of 98 frames of 33 bytes for a total of 3,234 bytes, or 1/75th of a second. See block level.
(2) A group of bits or bytes that is transmitted or processed as a single unit.
(3) A group of text characters that has been marked for moving, copying, saving or other operation.
(4) A rectangular group of pixels that are processed as a unit.
(5) A group of program statements that are treated as a unit based on the results of a comparison.