block -- Technical Information

A block is  a mass of data that is  read at one time.  Blocks are different
lengths  under different  operating systems;  COHERENT  defines a  block as
being BSIZE bytes long.

Information is read in blocks  from block-special devices, such as the hard
disk or floppy  disks.  This is done to increase  the speed with which data
are read from  these devices; reading characters one at  a time, such as is
done with  character-special devices such as terminals  or modems, would be
too slow.

See Also

Using COHERENT,
ANSI Standard, §3.6.2

© 2012 by Stephen A. Ness