a rack computer system . in one embodiment , a rack structure having a pair of mounting legs each having a rail interface oriented in a plane transverse to the pair of mounting legs . the rack computer system also has a computer chassis having a pair of mounting rails movable along the rail interface between a plurality of mounting depths oriented along the plane . in another embodiment , a method of forming a versatile rack mount . the method comprises providing a rack structure having dual mounting legs , coupling at least part of a rail and rail interface assembly to the dual mounting legs , and enabling variable - depth mounting of a desired computer chassis via the rail and rail interface assembly .