Tasks are made up of parametric operator instructions combined with calculations of the time required. Operator instructions can be input directly or can be built up from the pre-defined standard methods of the company.They can include references to parametric numeric data such as working envelope, accuracy and repeatability etc. or to parametric textual data such a method descriptions, process specifications, operator instructions etc. In addition the operator instructions can contain combined parametric method descriptions and parametric time/cost calculation blocks in the form of product or work centre related tasks and sub-tasks.