= Introduction to job processing =

Most distributed processing systems let you submit jobs -
you supply an executable and some input files,
and the system runs the job on a remote computer and
gives you the output files when it's done.
You can do this type of [SingleJob single job submission] in BOINC.

However, BOINC is designed for different types of situation, in particular those where:

 * You need to process thousands or millions of jobs, using only a few applications.
 * You want jobs to be '''platform-independent''', i.e. you don't have to specify what kind of computer to use.
 * You want job results to be validated by replication.

To handle these requirements, BOINC defines an architecture
in which jobs are processed in a pipeline consisting
of the following programs:

 * A '''work generator''' creates jobs.
 * A '''validator''' compares replicated results and selects one of them as 'canonical', or correct.
 * An '''assimilator''' handles validated results, storing them in an archive or database.

Typically these programs are application-specific,
and you will need to develop them (usually in C++) using
frameworks supplied by BOINC.
In some cases you may be able to use sample versions that are part of BOINC.
Each program should be listed as a [ProjectDaemons daemon] in the [ProjectConfigFile config.xml] file.

== Submitting jobs ==

To submit a job you must

 1. Write XML [JobTemplates template files] that describe the job's input and output files (typically the same template files can be used for many jobs).
 1. [JobStage Stage] the job's input file(s)
 1. Invoke a [JobSubmission BOINC function or script] that submits the job.

Once this is done, BOINC takes over: it creates one or more instances of the job,
distributes them to client hosts, collects the output files.
It [ValidationIntro validates] and
[AssimilateIntro processes] the results,
and deletes the input and output files.

Typically, steps 2) and 3) are done by a [WorkGeneration work generator] program
that creates lots of jobs.