A portable memory device includes an interface enabling communications between the portable memory device and an external device; a group of components arranged to provide a certain non-volatile electronic data storage when coupled to the interface. The coupling is performed based on one or more control signals, or on one or more configurations of one or more physical control elements that are transitionable by hand to different configurations, or both. When the group of components and the interface are coupled, the certain non-volatile electronic data storage is provided for use by an external device through the interface; when the group of components and the interface is not coupled or are decoupled, the certain non-volatile electronic data storage is not provided and instead another non-volatile electronic data storage may be provided or none at all. The portable memory device preferably is a flash memory apparatus and may encompass multiple flash-memory drives.