A semiconductor device includes a superlattice that, in turn, includes a plurality of stacked groups of layers. During the low power mode, portions of hardware, software, services, andor other components of the portable computer that are not necessary for email-related operations, such as polling a server for new email, are suspended or otherwise deactivated. Transaction requests in the first network protocol are selectively associated with the mapping windows. The keys are provided to the secure access controller by an authentication server.