NAND flash memory is a promising storage media that provides low-power consumption, high density, high performance, and shock resistance. Due to these versatile features, NAND flash memory is anticipated to be used as storage in enterprise-scale systems as well as small embedded devices. However, unlike traditional hard disks, flash memory should perform garbage collection that consists of a series of erase operations. The erase operation is time-consuming and it usually degrades the performance of storage systems seriously. Moreover, the number of erase operations allowed to each flash memory block is limited. This paper presents a new garbage collection scheme for flash memory based storage systems that focuses on reducing garbage collection overhead, and improving the endurance of flash memory. The scheme also reduces the energy consumption of storage systems significantly. Trace-driven simulations show that the proposed scheme performs better than various existing garbage collection schemes in terms of the garbage collection time, the number of erase operations, the energy consumption, and the endurance of flash memory.
Bibliographical noteFunding Information:
This research was supported by Basic Science Research Program through the National Research Foundation of Korea (NRF) funded by the Ministry of Education, Science and Technology (No. 2009-0077659 ) (No. 2010-0016216 ). The authors thank Hewlett Packard Laboratories for making their I/O traces available.
- Embedded systems
- Flash memory
- Garbage collection
- Storage systems