Abstract: One feature pertains to cooling of a high density array of non-volatile memory mass storage devices within a computer enclosure. A coolant is moved through the enclosure through two separate air paths, each serving approximately half of the mass storage devices. The two air paths are interleaved in a central duct ported to a frontal and a rear plenum. The central duct contains two groups of fans with a flow axis perpendicular to the plane of the server enclosure but with opposite flow direction with the two groups vertically offset relative to each other. The two paths are separated from each other through dividers. Both paths intake coolant from the cold isle and exhaust the coolant to the hot isle. The non-volatile memory mass storage devices include electromechanical and solid state devices.