Swap space management technique for portable consumer electronics with NAND flash memory

Flash memory has more capacity and a lower price. It makes flash memory more suitable for portable consumer electronics. Portable consumer electronics such as table PC and smart phones use NAND flash memory as a secondary storage because it has many attractive features such as small size, fast access speeds, and light weight. The portable consumer electronics with NAND flash memory exploit a "demand paging" to run applications, and also use a "swapping" to extend a limited main memory space. However, if the portable consumer electronics use NAND flash memory as swap space, it should perform garbage collection, which is a time-consuming operation. Therefore, in order to manage swap space efficiently, this work presents a novel garbage collection policy for the portable consumer electronics with a swap system. The proposed policy has three features important in NAND flash memory based swap systems: (1) long endurance of NAND flash memory, (2) quick garbage collection, and (3) low energy consumption.