Compressed Swapping for NAND Flash Memory Based Embedded Systems

A swapping algorithm for NAND flash memory based embedded systems is developed by combining data compression and an improved page update method. The developed method allows efficient execution of a memory demanding or multiple applications without requiring a large size of main memory. It also helps enhancing the stability of a NAND flash file system by reducing the number of writes. The update algorithm is based on the CFLRU (Clean First LRU) method and employs some additional features such as selective compression and delayed swapping. The WKdm compression algorithm is used for software based compression while the LZO is used for hardware based implementation. The proposed method is implemented on an ARM9 CPU based Linux system and the performances in the execution of MPEG2 decoder, encoder, and gcc programs are measured and interpreted.