Abstract: A portable personal computer that utilizes a combination of an open ended card cage and a passive backplane with a double-sided staggered array of connectors that allows for the horizontal placement of a large number of computer circuit boards in a low profile design as well as allowing easy access to the circuit boards for repair and replacement The open ended cage design also affords adequate cooling of the circuit components in the confines of a portable case. By hinging the card cage to the portable case, increased accessibility to the circuit boards is afforded. A welding data acquisition and control system embodiment is described that utilizes the portable computer for the acquisition of welding data for use in either operator or automated welding control. The system is capable of utilizing a wide range of welding programs for a wide rang of welding processes.