In one embodiment, a data storage device comprises a first flash memory, a second flash memory, and a controller. The field stop is constituted by a pair of etched troughs arranged in the pattern of an open chevron. \u201d When a tap is detected by a device, the device may initiate near field communication with the other tapping device. The aspiration catheter also includes infusion and aspiration lumen and port. The electron emission region has a first surface facing the first substrate and a second surface facing the second substrate. The global rate controller may provide a quality parameter to the plurality of encoders having a value based on the estimated coded sizes of the buffered coding units.