A written sign, a physical mark, a hole in a
data tape, a magnetic pattern, an electric signal or any discontinuity of matter which can be read or recognized (
see recognition ), is subject of
computing and whose meaning depends on the combinatorial context of other characters. So a "o" has a meaning different from "1," but the meaning of the combination, "10," has nothing to do with either. In the
binary system it means two and in the decimal system it means ten. Characters may become
symbols through
convention ally assigned meanings outside the recognition and computing process (
see datum, measurement ). (
Krippendorff )