Beyond the datasheet: Using test beds to probe non-volatile memories' dark secrets

Non-volatile memories (such as NAND flash and phase change memories) have the potential to revolutionize computer systems. However, these technologies have complex behavior in terms of performance, reliability, and energy consumption that make fully exploiting their potential a complicated task. As device engineers push bit densities higher, this complexity will only increase. Managing and exploiting the complex and at times surprising behavior of these memories requires a deep understanding of the devices grounded in experimental results. Our research groups have developed several hardware test beds for flash and other memories that allow us to both characterize these memories and experimentally evaluate their performance on full-scale computer systems. We describe several of these test bed systems, outline some of the research findings they have enabled, and discuss some of the methodological challenges they raise.