The value of 'hrDeviceIndex' corresponding to the directly
associated conceptual row in the 'hrDeviceTable' representing:
a) the first underlying 'physical' device (if any), if this
row has 'xcmHrDevInfoRealization' of 'logical'; or
b) the first subordinate 'physical' device (if any), if this
row has 'xcmHrDevInfoRealization' of 'physical' or
'logicalAndPhysical'; or
c) zero if there is no underlying or subordinate 'physical'
device associated with this row (ie, this device).