Two HDDs are mounted in a single hot swap twin pack tray. The orientation of HDDs—Printed Circuit Boards (PCBs) on HDDs are mounted facing inboard. HDDs operate in opposing directions (counter-rotational) to each other (i.e., so that the platters are spinning in opposite rotational direction, actuator arms are moving in opposite directions, and the motors are operating in opposite directions) providing smoother operation by dampening vibrations by cancelling each other's vibrations. The orientation of HDDs automatically provides protection for PCBs in dense environments.