The concepts were frankly pirated from the system used by a former employer, whose system in turn was based on one used in the airplane industry. Teaching apprentices is very much like having children. The Paperless Office Plenty has been written about our evolution towards the paperless office, but it seems few technology companies have made this transition even in the highest of the high tech environments - the engineering department. Sure, we now use schematic capture instead of a pencil and vellum, and word processors rather than scrawled notes, but almost all of these electronic documents get reincarnated in paper form. Production wants paper drawings for the assemblers.
Test needs test procedures and schematics on paper.
Let's face it - even engineering wants the schematics on paper. It's a lot easier to work with a paper schematic that you can scribble and make notes on then to call up the drawing on a screen somewhere. Electronic documents suffer from another flaw. That's the tack we've taken. The new reality of a drawing control system must recognize that while masters are inevitably in some computer format, working copies are almost always on paper.