 Joseph Orlickly and others at IBM developed a push approach to inventory control and production planning, now known as material requirements planning (MRP), which takes as input both the master production schedule (MPS) and the bill of materials (BOM) and gives as output a schedule for the materials (components) needed in the production process.MRP therefore is a planning tool to manage purchase orders and production orders (also called jobs).The MPS can be seen as a kind of aggregate planning for production coming in two fundamentally opposing varieties