The JFFS2 file system for flash memory compresses files before actually writing them into flash memory. Because of this, multimedia files, for instance, which are already compressed in the application level go through an unnecessary and time-consuming compression stage and cause energy waste. Also, when reading such multimedia files, the default use of disk cache results in unnecessary main memory access, hence an energy waste, due to the low cache hit ratio. This paper presents two techniques to reduce the energy consumption of the JFFS2 flash file system for power-aware applications. One is to avoid data compression selectively when writing files, and the other is to bypass the page caching when reading sequential files. The modified file system is implemented on a PDA running Linux and the experiment results show that the proposed mechanism effectively reduces the overall energy consumption when accessing continuous and large files.
Bibliographical noteFunding Information:
This research was supported by the National Research Laboratory (NRL) program of the Korean Science and Engineering Foundation (No. M10500000059-6J0000-05910) and the ITRC (Information Technology Research Center) support program supervised by the IITA (Institute for Information Technology Advancement, IITA-2008-C1090-0801-0015 and HY-SDR).
All Science Journal Classification (ASJC) codes
- Hardware and Architecture