The Workload Management System (WMS) comprises a set of grid middleware components responsible for the distribution and management of tasks across grid resources, in such a way that applications are conveniently, efficiently and effectively executed.

The core component of the Workload Management System is the Workload Manager (WM), whose purpose is to accept and satisfy requests for job management coming from its clients. For a computation job there are two main types of request: submission and cancellation.

In particular the meaning of the submission request is to pass the responsibility of the job to the WM. The WM will then pass the job to an appropriate Computing Element for execution, taking into account the requirements and the preferences expressed in the job description. The decision of which resource should be used is the outcome of a matchmaking process between submission requests and available resources.