Abstract: A pressure control system for a sealed enclosure may include opposing one-way valves to limit the differential pressure between the atmospheres internal and external to the sealed enclosure. The pressure control system may allow the internal atmosphere to vent out of a first one-way valve if the internal pressure exceeds the external pressure by a first predetermined pressure. The pressure control system may allow the external atmosphere to be drawn in through a second one-way valve if the external pressure exceeds the internal pressure by a second predetermined pressure. By allowing the exchange of gasses only when the differential pressure falls outside of a predetermined range, overall contamination may be reduced. By reducing the ingress of contaminants, such as dust, water, smog, and outgassed substances, performance may be improved and service life of components housed within the sealed enclosure may be extended.

Abstract: A half-height, 31/2-inch form factor disk drive architecture. The architecture includes at least six storage disks for storing data and a plurality of interactive read/write heads, two per disk, for reading information from and writing information on the storage disks. An actuator assembly, responsive to control signals, for selectively positioning the read/write heads with respect to the storage disks, and a latching mechanism are also included. Control electronics are provided on a printed circuit board to generate control signals to control the actuator means, and to provide information signals to and receive information signals from the read/write heads. The architecture also includes a housing defining the maximum height, length, and width of the disk drive, the housing having a maximum height of approximately one and 65/100 ths inches (1.