Any editing done on a system that has the ability to randomly access data can probably be characterized as non-linear editing. The term has historically been used to differentiate between editing with tape (whether splicing an audio tape or an A/B roll video editor) and the more modern conventions based on some type of computer system. But use of a computer does not in and of itself necessarily define editing as non-linear, nor does use of a tape machine have to mean that a system is not non-linear. For example, there have been systems that allow the user to enter time code values for edits, which are then carried out automatically by controlling tape machines (usually two playback machines and one record machine). Whether or not such a system is “non-linear” could be debated. In most cases, however, the line is pretty clear. A system where the user can define a region and move it forward or backward in relation to a sequence of other regions is clearly non-linear.