The Scheduler in DotNetNuke is both a module and a service.
Scheduler ModuleA module in DotNetNuke located under the Host -> Scheduler page. This module permits management of Scheduled Tasks in a DotNetNuke install. Users can also reach this module/page from the control panel or ribbon bar by clicking "Scheduler".
Scheduler ServiceA service in DotNetNuke that mimics how Windows Tasks operate.
Timer Mode & Request Mode