Formally, collections of symbols. This is the sense in terms such as
information processing, information technology, or information theory.
Symbols in turn may be defined as patterns that carry meaning, which therefore
serves as an alternative definition of information. A piece of information may
be regarded from three main viewpoints.
(a) From the human behavioral viewpoint,
some purpose underlies the creation of a piece of information, and some effect
(observed action or inferred state of mind) may follow from its receipt.
(b) From the analytical, linguistic viewpoint, a piece of information may be
described in terms of what it refers to, its meaning, and its structure.
(c) From the physical, engineering viewpoint, a piece of information may be
described in terms of its physical manifestation - the medium that carries it,
the resolution and accuracy with which it is inscribed, the amount that is
output, conveyed, or received, etc.
The following operations may be performed on information: create, transmit,
store, retrieve, receive, copy (in the same or a different form), process,
destroy. The patterns that constitute information may be created in a great
diversity of forms including: light, sound, or radio waves; electric current or
voltage; magnetic fields; marks on paper. In principle any conceivable material
structure or energy flow could be used to carry information. The scale of our
use of information is one of the most important distinctions between the human
species and all others, and the importance of information as an economic
commodity is one of the most important characteristics of the post-industrial
civilization, which we are often said now to be entering.