8th ACM International Conference on Embedded Software (EMSOFT 2008), pp.51 - 58
Abstract
Flash memory storage has been widely used in various embedded systems such as digital cameras, MP3 players, cellular phones, and DMB devices and now it applies to PCs as a form of SSDs. Characteristics of Flash memory necessitate a software layer called FTL (Flash Translation Layer) that directs modified data to new places in Flash memory and maintains a mapping between a logical sector number to a physical page. We notice that this out-of-place update scheme of the FTL allows a low-overhead time-shifting between multiple versions of storage state. From this observation, we propose LTFTL (Lightweight Time-shift FTL) that provides not only multiple versions of storage state but also an open-ended interface to traverse them. This open-ended interface can be used to support fault-resilience schemes, transactions of various granularities, and user-friendly roll-back services. Experimental results from a prototype implementation show that the proposed LTFTL can (1) provide a low-overhead time-shift capability at the user level by maintaining multiple storage states and (2) enhance the reliability/survivability of Flash memory by allowing to roll back to a previous consistent storage state at the storage system level.
Publisher
8th ACM International Conference on Embedded Software (EMSOFT 2008)