Drum, buffer, rope is the operations scheduling and control mechanism for the Theory of Constraints. The term comes from the notion that the constraint of the system is like a drum, beating out a pace for the entire system. The buffer is a supply of material designed to prevent the drum from running out of work. The rope is a signaling mechanism from the drum to material release to control the entry of material into the shop at the proper pace. The literature review covers the application of drum, buffer, rope in a variety of environments.