1 Computers: Getting Started
1.1.1 Data and information
A computer is a machine whose function is to accept data and process them into information. Data are facts or observations, while information is the meaning we attribute to them.
Let's use an example to illustrate. A medieval astronomer,Tycho Brahe, spent his entire adult life observing and recording the
positions of the planets. He collected data: on a given night,Mars occupied a given position in the sky. He recorded volumes of such data,but was never quite sure what they meant.
His successor, Johannes Kepler, sensedapattern: the orbit of Mars resembled an ellipse.He spent much of his life processing Brane's data, performing tedious computations and reorganizing the observations in an attempt to verify that pattern. Eventually he succeeded,publishing his laws of planetary motion in 1621.
Kepler's laws represent information. Using them, he could understand and predict the motions of the planets. Scientists and engineers still rely on his laws to help plan space flights.Information has meaning.
Clearly, Kepler's laws were derived from Brahe's data, but the raw data were useless without processing. Until they were organized and the necessary calculations performed, the data were unstructured facts, with no clear meaning. Knowing the exact position of Mars on the first April, 1599, might earn an extra move in Trivial Pursuit, but, by itself, that fact is not very useful.Processing data extracts their meaning.