• it compares redundant results and decides which ones are to be considered correct;
• it decides how much credit to grant to each correct result.

A validator is a daemon program. You must supply a validator for each application in your project, and include it in the <daemons> section of your project configuration file.

Depending on various factors, you may be able to use a standard validator that comes with BOINC, or you may have to develop a custom validator.

• If your application generates exactly matching results (either because it does no floating-point arithmetic, or because you use homogeneous redundancy) then you can use the 'sample bitwise validator' (see below).
• If you are using BOINC for 'desktop grid' computing (i.e. you trust all the participating hosts) then you can use the 'sample trivial validator' (see below).
• Otherwise, you'll need to develop a custom validator for your application. BOINC supplies a simple validator framework in which you plug in three short application-specific functions. This is sufficient for most projects. If you need more control over the validation process, you can use BOINC's advanced validator framework.

Two standard validators are supplied:

• The sample_bitwise_validator requires a strict majority, and regards results as equivalent only if they agree byte for byte.
• The sample_trivial_validator regards any two results as equivalent if their CPU time exceeds a given minimum.

Command-line arguments