Coherence (given)
See also: Coherence
In data processing, coherence is the capacity for a system to reflect on the copy of a data the modifications which have taken place on other copies this data. This concept is mainly used in three data-processing fields: the Filesystems, the Database, and the memories distributed.
General models
Strong coherence
A system in strong coherence ensures that any reading of a copy of a data will reflect any modification former to the reading occurred on any copy of the data.That is to say a data has. Maybe in {C1, C2,… Cn} of the copies of data. Let us suppose that C1 is modified in C1'. The management system of the data has ensures a strong coherence if any reading of a posterior copy Cx with the modification turns over C1'.
Weak coherence
A system in weak coherence ensures that if a copy is modified, all the copies of the data will reflect these modifications at the end of a certain time.
Other models
Models without synchronization
Atomic coherence
This model of coherence is strongest which is. A data is modified when the readings and writings on the copies of the data are finished. The readings or writings intervening on the copies c1 during a phase of writing will be suspended time that the modifications induced by this writing are reflected on all the copies.
- causal Coherence
- sequential Coherence
- Coherence PRAM
- Coherence object
- Coherence with long the
Models with synchronization
- weak Coherence
- Coherence with the relaxation
- Coherence at the entry
| Random links: | Elsie Lefebvre | Anna Cross-country race | Fischingen | Teufelsberg | Bjelotići | M._Music_Head |