Effective management of compressed data with packed file systems

Summary form only given. Lossless data compression is commonly used on personal computers to increase their storage capacity. For example, we can get twice the normal capacity by using lossless data compression algorithms. However, it is necessary to locate compressed data of variable sizes in a fixed-size block with as little fragmentation as possible. This can be accomplished by compressed data management (CDM). The amount of storage capacity provided by data compression depends on the ability of CDM. If CDM does not eliminate fragmentation sufficiently, one cannot attain the storage capacity corresponding to the compression ratio. We present an efficient CDM using a new packed file system (PFS). We confirmed that the PFS achieves and maintains 95% of high space efficiency by using only 1/1000 of the table size needed for the entire storage capacity without employing garbage collection.