Checksums and error control

Computing has always had to live with errors, especially in data transmission and data recording. Sometimes these errors are only a nuisance and a simple retry can obtain satisfactory, accurate, data. But sometimes an error can be serious, and perhaps even disastrous if an accurate original copy is inaccessible. Two related, but somewhat parallel disciplines, have developed to deal with the handling of erroneous data, both part of the general theme of “Coding Theory” and collected under the generic title of “Error Control”.