Real-Time Program Execution on NAND Flash Memory for Portable Media Players

NAND flash memory has been widely used as a non-volatile storage for storing data. However, it requires a large amount of SRAM for executing program codes stored in it since it only supports page-based reads, not byte-level random reads. This paper proposes a new paging mechanism called RT-PLRU (real-time constrained combination of pinning and LRU) that allows program codes stored in NAND flash memory to be executed satisfying real-time requirements with minimal usage of SRAM. Moreover, the RT-PLRU is optimally configured in a developer-transparent way without giving any burden to the program developer. The developed technique is specifically applied to a media player program targeting a PMP (portable medial player). To the best of our knowledge, this is the first effort to use NAND flash memory as a code storage for storing and executing real-time programs with minimal usage of SRAM.