How to create an efficient drawing management system for CAD

Preamble
The heart of a good Engineering office is a good drawing management system. It should be simple to produce such a system. But typically it hasn't been. Large Engineering manufacturers usually employ substantial resource to this part of the system and most will have a fairly sophisticated process. They need it, in order to operate. Assemblies, sub assemblies, individual components, clearly identifiable and manageable. The automobile, the aircraft, the washing machine, it is essential that they have systems and staff to manage the systems, so as to make it work. In the days before computers, manufacturers would generally use a fairly sophisticated combination of letters and numbers in order to segregate and group components and systems. Human error was very common.