Abstract: A memory device has a plurality of memory blocks utilized to store data. One of the blocks is used as a hidden memory block to store an operating system program, instead of data. The hidden memory block is designated as a bad block so that data will not be written into the hidden memory block, but a tag associated with the hidden memory block identifies that the hidden memory block contains the operating system program.

Abstract: A flexible memory interface system includes a control module, instruction memory, a command processing unit, an address processing unit, and a data processing unit. The control module controls storing and retrieving of a command portion, an addressing portion, and data of an instruction to access memory to and from the instruction memory and the command processing unit, the address processing unit, and the data processing unit, respectively. The command processing unit is operably coupled to process a command portion of an instruction to access memory. The address processing unit is operably coupled to process an addressing portion of the instruction to access the memory. The data processing unit is operably coupled to process data conveyance to or from the external memory based on the instruction to access the memory.