A method for control of multiple operating systems is applied to detect whether a Hard Disk Drive is connected with a system bus of an electronic machine by using a Basic Input and Output System. The PHY communicates with a higher-layer device using a packet protocol. In some embodiments, the etching gas comprises hydrogen chloride and germane. 015 parts by weight of metal salt of carboxylic acid as a catalyst for coupling reaction, is heated at a temperature higher than a melting point of said polyester resin. The viewer perceives the foreground image and the background image as part of a scene having depth.