Strong consistency is one of the
consistency model
In computer science, a consistency model specifies a contract between the programmer and a system, wherein the system guarantees that if the programmer follows the rules for operations on memory, memory will be consistent and the results of rea ...
s used in the domain of
concurrent programming
Concurrent means happening at the same time. Concurrency, concurrent, or concurrence may refer to:
Law
* Concurrence, in jurisprudence, the need to prove both ''actus reus'' and ''mens rea''
* Concurring opinion (also called a "concurrence"), a ...
(e.g., in
distributed shared memory
In computer science, distributed shared memory (DSM) is a form of memory architecture where physically separated memories can be addressed as a single shared address space. The term "shared" does not mean that there is a single centralized memo ...
,
distributed transactions).
The protocol is said to support strong consistency if:
# All accesses are seen by all parallel processes (or nodes, processors, etc.) in the same order (sequentially)
Therefore, only one consistent state can be observed, as opposed to
weak consistency, where different parallel processes (or nodes, etc.) can perceive variables in different states.
See also
*
CAP theorem
In theoretical computer science, the CAP theorem, also named Brewer's theorem after computer scientist Eric Brewer, states that any distributed data store can provide only two of the following three guarantees:Seth Gilbert and Nancy Lynch"Brewer ...
References
Consistency models
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