Validator Daemon

[edit] General

A Validator Daemon is a Back-End Program that does Validation and credit-granting. The Project Developers must supply a Validator Program (which is run as a Validator Daemon) for each Application in a BOINC Powered Project.

The Validator only looks on those Work Units where the NEED_VALIDATE flag is set.
The Validator in contrast to the Transitioner Daemon has also 2 project-specific functions, check_set and check_pair, this means that different BOINC Powered Projects don't need to act the same way.
The Validator used by SETI@Home, for example, was mostly programmed during BOINC-beta, and at the time min_quorum was 2.
The Validator used by SETI@Home therefore checks Results with a "success" Outcome pairwise until it finds a pair that is "strongly similar". It then marks both of the Results "Valid" and chooses one of them as "Canonical Result". If after checking all possible combinations didn't find a pair, it's "no consensus yet" and must wait on another Result if didn't hit any of the error-limits (see Quorum of Results for details).
If a Work Unit is validated, remaining Results, if any, are then compared against the "Canonical Result" if they are "weakly similar" and is marked valid/invalid accordingly.
At the end, the Validator chooses the amount of Granted Credit to be awarded by using the basic formula:
1. If only 2 Results passed validation, use the lowest Claimed Credit.
2. If 3 or more Results passed validation, remove highest and lowest Claimed Credit and average the rest.

Note:

See the section "Credit Granting Rules" in Credit for the complete set of rules that can be used.