A card adapter includes a plurality of memory card interfaces for interfacing with a plurality of memory cards, each of the memory cards having its own file system, and a host interface for interfacing a host of the memory cards. A controller of the card adapter interfaces with the plurality of memory card interfaces and with the host interface and controls operation of the memory cards. The card adapter may have several modes of operation, one of which involves emulating, on the host, by the controller, a virtual file system that represents a unified image of the file systems of two or more memory cards. In another mode of operation of the card adapter the controller establishes presents to the host only one file system of a memory card.