From Unofficial BOINC Wiki
This is the actual running process (or program) that coordinates the work that is issued to make the best use of the computers available to process the work that is ready for issue. This is the process that is contacted by the BOINC Client Software on a Participant's Computer when the BOINC Daemon determines that it needs more work to fill the Work Buffer.
This process may be run on a single dedicated Server, or may be combined with other Back-End Processes that are part of the BOINC System. The Scheduler Daemon is run as an always available BOINC Server-Side Daemon Program process.
Though some may find this to be circular reasoning, the Scheduling Server is the server on which the Scheduler Process is running. This is not an exclusion in that the same Physical Server may also be the Data Server.
The "BOINC Scheduler" is a little bit of a misnomer. There is not really a monolithic program that stays in existence as we know it. The "BOINC Scheduler" is actually a bunch of "instances" of a CGI script (or Fast-CGI) that communicate with the Participant's Computer when they send a Scheduler Request Message. When the Scheduler Request Message is received by the Scheduling Server it creates an instance of the Scheduler CGI script which then processes the Scheduler Request Message.
Because of the overhead of connecting to the MySQL database engine, the "BOINC Scheduler" connects to the BOINC Database through the intermediary program we know as the "Feeder". This program makes one connection to the BOINC Database and creates and maintains the Ready To Send Queue of Results that are pending issue to the BOINC Client Software.
- Scheduler Daemon
- Scheduler Process