Patent ID: 8112752

Claim:
A method for performing a software process, the process comprising a plurality of tasks, the method comprising: starting a task of the plurality of tasks of the process; monitoring a progress of the started task; comparing the progress with a desired progress; if the progress does not meet the desired progress, skipping at least a part of a task of the plurality of tasks based on a priority list; and providing an output of the process making use of an outcome of the tasks which have been completed; wherein the software process comprises a combined long stroke-short stroke position controller of a lithographic apparatus substrate table, a short stroke position controlling task of the position controller being ranked higher in priority on the priority list than a long stroke position controlling task of the position controller and wherein the position controller comprises a proportional, integrating, differential controller, a priority of the proportional, integrating, differential controller being lower than the priority on the priority list of the position controller.