In this invention, image data expressed by one component is encoded at a high speed by using a color image lossless encoder. The keypad assembly has a plurality of alphanumeric keys for user entry of alphanumeric characters and a navigation input device for user entry of plural directional inputs. The first and second openings are alignable with one another when the cap is detachably attached to the rear portion of the main body to enable a tether to be threaded through the aligned openings for tethering the writing instrument to an object. English, language phonetic equivalents of at least one language character including a language character intended by the user to form a word construct in a language. Thus, the clearance is maintained as small as possible in operation and gas turbine performance is enhanced. When the operation reception means receives a slide operation sliding the pressing means on the touch panel, the display control means moves and displays display data of one display screen on another display screen.