|Noun||1.||redundancy - repetition of messages to reduce the probability of errors in transmission|
|2.||redundancy - the attribute of being superfluous and unneeded; "the use of industrial robots created redundancy among workers"|
|3.||redundancy - (electronics) a system design that duplicates components to provide alternatives in case one component fails|
|4.||redundancy - repetition of an act needlessly|
REDUNDANCY. Matter introduced in an answer, or pleading, which is foreign to
the bill or articles.
2. In the case of Dysart v. Dysart, 3 Curt. Ecc. R. 543, in giving the judgment of the court, Dr. Lushington says: "It may not, perhaps, be easy to define the meaning of this term [redundant] in a short sentence, but the true meaning I take to be this: the respondent is not to insert in his answer any matter foreign to the articles he is called upon to answer, although such matter may be admissible in a plea; but he may, in his answer, plead matter by way of explanation pertinent to the articles, even if such matter shall be solely in his own knowledge and to such extent incapable of proof; or he may state matter which can be substantiated by witnesses; but in this latter instance, if such matter be introduced into the answer and not afterwards put in the plea or proved, the court will give no weight or credence to such part of the answer."
3. A material distinction is to be observed between redundancy in the allegation and redundancy in the proof. In the former case, a variance between the allegation and the proof will be fatal if the redundant allegations are descriptive of that which is essential. But in the latter case, redundancy cannot vitiate, because more is proved than is alleged, unless the matter superfluously proved goes to contradict some essential part of the allegation. 1 Greenl. Ev. Sec. 67; 1 Stark. Ev. 401.
|1.||(parallel)||redundancy - 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.||(communications)||redundancy - The proportion of a message's gross
information content that can be eliminated without losing
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]