Error Correction and Partial Information Rewriting for Flash Memories

This paper considers the partial information rewriting problem for flash memories. In this problem, the state of information can only be updated to a limited number of new states, and errors may occur in memory cells between two adjacent updates. We propose two coding schemes based on the models of trajectory codes. The bounds on achievable code rates are shown using polar WOM coding. Our schemes generalize the existing rewriting codes in multiple ways, and can be applied to various practical scenarios such as file editing, log-based file systems and file synchronization systems.