Although they use simple arithmetic, MRP systems would be impractical without digital computers. MRP crusade . Thanks to the efforts of highly motivated consultants, along with a computer industry eager to expand the range of its services, there were more than one billion dollars worth of MRP systems in service by 1989. An MRP system bases orders for component parts on demand for finished goods. MRP systems draw a clear distinction between independent and dependent demand.
Independent demand originates outside the plant, generally from customers.
This can include demand for finished goods and repair parts. Dependent demand originates as a result of independent demand. When a customer places an order, this creates a need every component part necessary to create the finished good or repair part in question. An MRP system creates a production plan for the manufacture of necessary components, and a purchasing schedule for the acquisition of necessary purchased components. Although the details of MRP systems vary, they share common themes.