redundancy : Dictionary / Wörterbuch (BEOLINGUS, TU Chemnitz)

English Dictionary: redundancy	by the DICT Development Group
3 results for redundancy
From WordNet (r) 3.0 (2006) [wn]:
redundancy n repetition of messages to reduce the probability of errors in transmission the attribute of being superfluous and unneeded; "the use of industrial robots created redundancy among workers" Synonym(s): redundancy, redundance (electronics) a system design that duplicates components to provide alternatives in case one component fails repetition of an act needlessly
From Webster's Revised Unabridged Dictionary (1913) [web1913]:
Redundance \Redun"dance\ (r?d?n"dans), Redundancy \Redun"dancy\ (-dan*s?), n. [L. redundantia: cf. F. redondance.] 1. The quality or state of being redundant; superfluity; superabundance; excess. 2. That which is redundant or in excess; anything superfluous or superabundant. Labor . . . throws off redundacies. --Addison. 3. (Law) Surplusage inserted in a pleading which may be rejected by the court without impairing the validity of what remains.
From The Free On-line Dictionary of Computing (15Feb98) [foldoc]:
redundancy 1. The provision of multiple interchangeable components to perform a single function in order to cope with failures and errors. Redundancy normally applies primarily to hardware. For example, one might install two or even three computers to do the same job. There are several ways these could be used. They could all be active all the time thus giving extra performance through {parallel processing} as well as extra availability; one could be active and the others simply monitoring its activity so as to be ready to take over if it failed ("warm standby"); the "spares" could be kept turned off and only switched on when needed ("cold standby"). Another common form of hardware redundancy is {disk mirroring}. Redundancy can also be used to detect and recover from errors, either in hardware or software. A well known example of this is the {cyclic redundancy check} which adds redundant data to a block in order to detect corruption during storage or transmission. If the cost of errors is high enough, e.g. in a {safety-critical system}, redundancy may be used in both hardware AND software with three separate computers programmed by three separate teams and some system to check that they all produce the same answer, or some kind of majority voting system. 2. The proportion of a message's gross information content that can be eliminated without losing essential information. Technically, redundancy is one minus the ratio of the actual uncertainty to the maximum uncertainty. This is the fraction of the structure of the message which is determined not by the choice of the sender, but rather by the accepted statistical rules governing the choice of the symbols in question. [Shannon and Weaver, 1948, p. l3] [Better explanation?] (1995-05-09)