Abstract: A multilayer printed circuit memory board is designed and constructed so that the top and bottom layers contain repetitive integrated circuit (IC) chip component hole/pad and interconnection line patterns which are mirror images of one another. The board uses surface mounted techniques in which the integrated chip components of the memory array are mounted and soldered to both sides of the board thereby doubling the density or capacity of the memory board. The integrated circuit memory chips, mounted on the top and bottom of the board, are aligned with each other for sharing common holes or vias in which logically equivalent input signal connections are exchanged in a manner for reducing the number of holes and length of connective wiring.

Abstract: An electronic computer includes a plurality of printed circuit boards that are slideably mounted in spaced parallel planes within a housing. The housing contains an input/output bus arrangement which is substantially open in the middle. A power supply is detachably mounted to the housing in such a manner as to automatically connect to the input/output bus arrangement when it is secured in place. The power supply includes suction fans which draw ambient air in through the front of the housing over the printed circuit boards, through the open portion of the bus arrangement and hence over critical portions of the power supply. The air is initially drawn through perforated openings in a hinged control panel in one preferred embodiment. In another preferred embodiment, the air is drawn through a stationary member at the front of the housing.