Patent ID: 7962685
Filing Date: 2011-06-14
Classification: G06F,G11C

Abstract:
1. A portable data storage device comprising: (a) an interface for enabling the portable data storage device to transfer data with a host computer; (b) an interface controller for controlling the interface; (c) a non-volatile memory comprising at least one single layer cell flash (SLC) memory and at least one multiple layer cell (MLC) flash memory; and (d) a master controller for controlling the writing of data to, and reading data from, the non-volatile memory, the master controller being operable: upon the interface receiving a write instruction from the host, to identify a flash memory from among said flash memories, and to write data specified by the write instruction to the identified flash memory, and upon the interface receiving a read instruction from the host, to identify the flash memory from among said flash memories, and to read data from the identified flash memory, wherein the master controller is operable to identify the flash memory based on a logical address contained in the instruction and with reference to a mapping table storing a sequence of logical addresses and a mapping between the logical addresses and physical addresses, such that in the sequence of logical addresses, SLC logical addresses alternate with MLC logical addresses, each SLC logical address corresponding to a predefined number of blocks of SLC addresses, and each MLC logical address corresponding to a predefined number of blocks of MLC addresses.