The Atomicity reference article from the English Wikipedia on 24-Apr-2004
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Atomicity

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In concurrency control (Is this a field in computer science? If so, please say so.), atomicity implies that either all or no operations are completed. See concurrent programming.

Atomicity in the component-based paradigm context

Atomicity is an element of orthogonality guaranteeing hermetic interfaces among components of a component-based system. This avoids that malfunctions in one component would result into side-effects in another. In addition it guarantees that services provided by a component are either offered as a whole, or not at all. Systems build according to this design principle localise the side-effects of changes within the module that such change was manifested. Changes affect the emergent behaviour of such a system only if their technical effect is explicitly described by the formal definition of its logic.