Compressed common file directory for mass storage systems

Abstract

A file management system for accessing mass storage systems, employing a compressed common file directory ('CCFD') that occupies a minimum amount of storage space. The CCFD is implemented in a storage system including a library of media, one or more storage drives that may be permanently or selectively coupled to the media, and a controller connected. Each piece of media includes a local file directory, which contains a listing of the files stored on that piece of media cross-referenced to those files' addresses on the media item. The controller contains or has convenient access to the CCFD. When access to a file is desired, the CCFD is used to quickly identify the piece of media containing that file. More particularly, the CCFD includes a first data structure including a list of encoded filenames cross-referenced to a list oil compressed media IDs. Each encoded filename comprises a filename of a file stored in one or more of the media, encoded with a selected encoding scheme. For each encoded filename, the associated compressed media ID comprises an encoded name of a piece of media containing that file. A second data structure includes a list of each compressed media ID cross-referenced to a media location identifier specifying the location of that media item in the library. To access a desired file stored in the library, the file's name is first encoded. Then, the encoded filename is cross-referenced in the first data structure to obtain a compressed media ID. Using the second data structure, the compressed media ID is used to determine the media's location identifier. The media location identifier is then used to locate the media containing the file. After the media is located and obtained, the media's local file directory is searched to find the desired file's address in that piece of media.