The development of PC-based controllers is increasingly vigorous, which is demonstrated in the international machinery exhibitions in recent years. For instance, in the two machine tool exhibitions that Taiwan companies participated, Chicago IMTS of 1996 and Tokyo JIMTOF of 1996, the competition between Taiwan companies can be figuratively described as 'more than hundred companies contending for the market.' Many people believe that the open architecture development of PC-based controllers will eventually replace the traditional closed-end CNC market in the future....