The System ID.
This value indicates the system ID of the system board
in this system. This ID replaces the product ID used in
older machines (cpqSiProductId). A value of 7Eh for the
cpqSiProductId indicates that the cpqSiSystemId should be
used to identify the system. A value of zero (0)
indicates that the system ID function is not supported on this
machine. In this case, the cpqSiProductId should be used to
identify the system.