MRP and DRP are systems that have been developed as planning tools that makes the material available when they are actually needed. The concept originated from materials requirement planning, an inventory control technique that determines demand for manufacturing supply. As a result Manufacturing Resource Planning (MRPII) has been developed to address productivity improvements. MRPII is based on the integration of the whole manufacturing process from customer orders through the production planning and control stages to the purchasing and supply of materials.

DRP is the application of MRPII (MRP2) techniques to the management of inventory and material flow. DRP operates by separating the flow of material from the source of supply. This looks at the time taken for the product to flow through the individual stages of the supply chain ensuring it is at the right place at the right time.

JIT originated from a new approach to manufacturing and has been successfully adopted in many industries such as the automotive industry. As such this approach has had a significant impact on distribution and logistics. The underlying concept of just in time is to provide a production system that eliminates all activities that neither adds value to the final product nor removes wasteful practices within a production process. Just in time is a pull’ system of production, so actual orders provide a signal for when a product should be manufactured. Demand - pull enables a firm to produce only what is required, in the correct quantity and at the correct time.