Abstract: A personal digital unit includes an image display together with a software-driven processor for managing the display. The display also includes a writing input capability. The display is divided into a more comprehensive window and a less comprehensive writing window. A locator rectangle is added to the image within the more comprehensive window and corresponds in proportionate position and size to the location and size of the writing window within the virtual page of the display.

Abstract: A keystroke chording system operative within a computing system such as a PDA or the like employs the multi-position joystick control or its equivalent together with a plurality of discreet input buttons to provide text entry. The system utilizes highly effective chording techniques to allow the user to employ additional shift keys positioned upon the PDA computing unit to increase the available combinations of chorded keystrokes produced by joystick and action button actuation of the unit. The use of additional shift keys facilitates a highly effective and efficient chorded keystroke system.

Abstract: A pen-based computer is operative to produce a drawn image upon a touch-sensitive display screen. A stylus or pen is utilized in combination with the pen-based computer or touch input to the display screen. An interface system implemented using software additions to the operating system of the computer processor provides a designated button or dedicated button input to the system which facilitates mode selection by simple actuation or non-actuation. In this manner, the stylus or pen need not be lifted from the display screen to access panning or scroll sub routines during writing, drawing, editing or the like.