This Counter reports the upper (high-order) word of the total physical storage capacity of the IO Drive in bytes, to be combined with the lower word for the full 64-bit value. An admin combines this with the paired lower-word object to determine the card's true raw physical capacity, which is important since actual usable capacity differs due to overprovisioning. For example, a nonzero value here indicates the card's total physical capacity exceeds what a single 32-bit counter could represent alone.