The present invention relates generally to computer systems, and more particularly to synchronously sharing data between computer systems.
Computerized personal organizers are becoming increasingly popular with a large segment of the population. Computerized personal organizers tend to be small, lightweight, and relatively inexpensive, and can perform such functions as keeping a calendar, an address book, a to-do list, etc. While many of these functions can also be provided in conventional computer systems, personal organizers are very well suited to the personal organization task due to their small size and portability. Personal organizers are available from such companies as Sharp and Casio of Japan.
A relatively new form of computer, the pen-based computer system, holds forth the promise of a marriage of the power of a general purpose computer with the functionality and small size of a personal organizer. A pen-based computer system is typically a small, hand-held computer where the primary method for inputting data includes a "pen" or stylus. A pen-based computer system is commonly housed in a generally rectangular enclosure, and has a dual-function display assembly providing a viewing screen along one of the planar sides of the enclosure. The dual-function display assembly serves as both an input device and an output device. When operating as an input device, the display assembly senses the position of the tip of a stylus on the viewing screen and provides this positional information to the computer's central processing unit (CPU). Some display assemblies can also sense the pressure of the stylus on the screen to provide further information to the CPU. When operating as an output device, the display assembly presents computer-generated images on the screen.
The dual-function display assemblies of pen-based computer systems permit users to operate the computer as a computerized notepad. For example, graphical images can be input into the pen-based computer by merely moving the stylus on the surface of the screen. As the CPU senses the position and movement of the stylus, it generates a corresponding image on the screen to create the illusion that the stylus is drawing the image directly upon the screen, i.e. that the stylus is "inking" an image on the screen. With suitable recognition software, text and numeric information can also be entered into the pen-based computer system in a similar fashion.
Once information is entered, the ability to share that information, either asynchronously or synchronously, with other systems is important to the advancement of computer usage. With asynchronous communication, a specific action or command must be performed to share entered data between systems. Data changes are therefore not shared until a user explicitly transmits them. This results in a delayed WYSIWIS (What You See Is What I See) interface among users. While this type of data exchange is beneficial, the ability to simultaneously share information between a plurality of systems as it is entered creates new opportunities to make computers an even greater tool. Such data exchange creates interpersonal communication, i.e., a conversation, between computer users and is achievable through synchronous data sharing. This synchronous communication allows several users to participate in data exchange at the same time to create a real-time WYSIWIS interface, so that collaboration of ideas occurs in much the same way as if the participants were in the same room and using the same sheet of paper or blackboard.