SanDisk/Fusion-io's NVMFS file system, formerly known as Direct File System (DFS), accesses flash memory via a virtual flash storage layer instead of using the traditional block layer API. This file system has two main novel features. First, it lays out files directly in a very large virtual storage address space. Second, it leverages the virtual flash storage layer to perform block allocations and atomic updates. As a result, NVMFS performs better and is much simpler than a traditional Unix file system with similar functionalities. Additionally, this approach avoids the log-on-log performance issues triggered by log-structured file systems. Microbenchmark results show that NVMFS can deliver 94,000 I/O operations per second (IOPS) for direct reads and 71,000 IOPS for direct writes with the