A pen-based form computer using "Form" as the operation metaphor between users and the computer, which allows an user to directly operate the information stored in the computer or any remote systems without learning commands, file names, file types, and other details regarding computer internal structure. It is applicable for use in medical prescription control, order registration control, inventory inquiry control, data collection. It can also be used as a front-end system in a client and server structure. The pen-based form computer comprises a pen for data entry, and a complete Multi-tasking Preemptive Pen Based Form Operation software system for form operation metaphor, graphical form making procedure, multiple form data association, multiple form operation language, remote form data accessing, automatic database association, and hand-writing recognition. External keyboard for data entry is acceptable. The preferred embodiment of the invention is within 2 lbs and about the size of a B5 paper. It uses a pressure-sensitive touch panel overlaid LCD for data entry with the pen, and an infrared, RS-232, off-the-shelf modem, and radio transceiver as communication mediums.