Dave Abbe wrote a good topic on this and cannot find it now,
hope this helps a bit
Plain Barrel: i.e. without teeth, used in fusee watches and clocks. A chain, or cord, was wound around the plain barrel, connecting it to the fusee.
Going barrel: the form used in modern watches, is wound by turning the arbor and drives the watch movement by a ring of teeth around the barrel. This enables the mainspring to continue running the watch while it is being wound.
Hanging Barrel: a version of the going barrel that to save space is supported by the movement only at its upper end.
Motor or safety barrel: used in pocketwatches around 1900, a reverse variant of the going barrel in which the spring is wound by turning the barrel, and turns the watch movement by the central arbor. The purpose of this arrangement was that if the spring breaks, destructive recoil forces would not be applied to the vulnerable gear train.