The DC-API was created by MTA SZTAKI to allow easy implementation and deployment of distributed applications on multiple grid environments. In order to accomodate the needs of very different grid environments, the DC-API supports only a restricted master-worker programming model. The restrictions include: Master-worker concept: there is a designated master process running somewhere on the grid infrastructure. The master process can submit worker processes called work units. Every work unit is a sequential application. There is support for limited messaging between the master and the running work units. It can be used to send status and control messages, but it is not suitable for parallel programming. There can not be any direct communication between work units.