Compaction and compression techniques for file systems based on persistent memories

File systems are the most popular means of data storage in many computing environments. The appropriate designs of file systems therefore become key research highlights to enhance the data access performance and storage space utilization. As diversified persistent memories (PMs) are considered powerful competitors of mechanical hard disks due to their ideal access performance and energy efficiency, file system designers need to adopt various compression or compaction techniques to reduce the space wastes, because the storage density of PMs are still considerably lower than that of hard disks. However, there are still missing pieces in the puzzle which overviews the potential approaches that enhance the storage space utilization from various perspectives of a file system. In this work, we shall take a revisit to the promising techniques that help enhance the storage space utilization of file systems based on PMs. It is observed that an effective compression or compaction technique not only benefits the storage space utilization, but also ameliorates the access performance of the file system.