Abstract: A portable data storage device includes a USB controller, a master control unit and a NAND flash memory device. The master control unit receives data to be written to logical addresses, and instructions to read data from logical addresses. It uses a memory address mapping table to associate the logical addresses with the physical addresses in the memory device, and writes data to or reads data from the physical address corresponding to the logical address. The mapping is changed at intervals, so that different ones of the physical address regions are associated at different times with the logical addresses. This increases the speed of the device, and also means that no physical addresses are rapidly worn out by being permanently associated with logical addresses to which data is written relatively often.

Abstract: A portable data storage device (10) includes a universal serial bus (USB) coupling device (1) and an interface device (2) is coupled to the USB coupling device (1). The portable data storage device (10) also includes a memory control device (3) and a non-volatile solid-state memory device (4). The memory control device (3) is coupled between the interface device (2) and the memory device (4) to control the flow of data from the memory device (4) to the USB coupling device (1). An authorization input is received from the user of the portable data storage device, a comparison is made comparing the authorization input from the user of the portable data storage device with authorization data stored on the portable data storage device; and access to requested data is granted or denied depending on whether the authorization input from the user corresponds to the stored authorization data.

Abstract: A portable data storage device (10) includes a universal serial bus (USB) coupling device (1) and an interface device (2) is coupled to the USB coupling device (1). The portable data storage device (10) also includes a memory control device (3) and a non-volatile solid-state memory device (4). The memory control device (3) is coupled between the interface device (2) and the memory device (4) to control the flow of data from the memory device (4) to the USB coupling device (1).