In one aspect, the technology includes a portable system, for providing add-on resources to a host device, such as a vehicle host device. The portable system includes a portable-system resource, which in various embodiments is at least partially a part of a portable-system data storage. The data storage includes at least one companion application that, when executed, provides, based on operation of the portable-system resource, host-device output for use at the host device, wherein the host-device output is output that the host device could not produce on its own or is supplemental to output that the host device can produce on its own. Example portable-system resources include a central-processing unit, a graphics processor, an application shop, an app-refresh program, security or hardware accelerators, and a speech recognition or three-dimensional rendering program. The technology in various embodiments also includes the host device described herein.