Graphical password methodology for a microprocessor device accepting non-alphanumeric user input

A portable computing device or "information appliance" having terse user input (e.g., limit set of keys) is provided with a user interface for navigating user data. Application programs, which are provided for user operation of the device, are implemented as separate modules controlled by a module selector. The module selector serves as a user interface or shell representing the top-level or "home" display presented to a user. The module selector presents the user with selection icons for navigating to different applications or modules of functionality. The user interface implements a "single-click" style of button operation, so that users can associate each button with a particular task for a given program context. In addition to the single-click style, "click consistency" is imposed for each button. Generally, the same buttons are used over and over again to perform their respective tasks, even though the user has navigated to different modules of an application, so that the user is presented with a consistent interface or metaphor which can be easily mastered. The user interface supports in a small form factor device the browser-style navigation that users have become accustomed to on desktop computers (e.g., using Web browsers). More particularly, the interface supports up, down, forward, and backward navigation for allowing a user to "drill down" to "drill across" his or her data. This allows the user to find a data item (link) of interest and then drill down into it. Once at the appropriate level, the user can then easily select the particular item of interest. Further, once the user has selected or entered an item, the system provides the ability for the user to return to "home" with a single button click. In this manner, the present invention provides an interface allowing browser-style navigation in a device having a terse set of input keys.