Abstract: To improve the serviceability, manufacturability and uptime for a computer file server a specially designed planar/riser card assembly is mounted on the computer chassis and includes a card cage structure in which a riser card is secured. Carried on the riser card are I/O card edge connector sockets into which all of the system I/O cards may be plugged. The riser card is hard connected into the system and itself has an edge connector portion. The system planar board is carried on a mounting plate which is screwed to an outer side of the cage structure. A socket connector carried on the planar board receives the edge connector portion of the riser card, thereby electrically coupling the planar board to the riser card. The riser serves as a wiring plane containing only the signals which the planar board would normally provide to the I/O cards through "on planar" connectors.