Portable data processing system including replaceable fuel cell apparatus and method of operating it

A system in accordance with a present invention includes a host device (100,100') and a fuel cell apparatus (132,208) with an information storage device (200). A method of operating a host device (100,100') in accordance with a present invention includes the step(s) of writing data to, and/or accessing data on, a fuel cell apparatus information storage device (200). A fuel cell driven information processing device such as a personal digital assistant (PDA) comprises a replaceable fuel cell apparatus including a fuel cartridge. A host device configured to receive the replaceable fuel cell apparatus records maintenance information on a fuel cell information device and monitors fuel consumption.