FILE SYSTEM IMPLEMENTING WRITE ONCE READ MANY (WORM)

摘要

The embodiments deal with files that are already present in a storage when mounting the storage in a file system and files created after the mounting as different groups. (Metadata of) the files is classified. The files are each divided into metadata (index) and a file main body and are recorded on different storage areas, that is, an index partition (IP) and a data partition (DP), associated with each other. This file system is effective in a storage format in which a new file is merely written and an already written file is not updated or deleted (for example, a tape medium used in the LTFS). The embodiments implement a WORM file system by rejecting a request to update or delete a file that is present at mounting as a WORM file and permitting update or deletion of a file that is created after mounting until the storage is unmounted.

主权项

1. A method for a file system to classify files in a mounted storage in a storage format in which the files are each divided into metadata and a file main body and are recorded in association with each other, and in which a new file is merely written, and an already written file is not updated or deleted, the method comprising:
(a) determining whether a file present in the mounted storage has already been present in the storage when the storage is mounted; (b) classifying, using a processor and a memory, a file determined to have already been present in the storage when the storage is mounted as a first group in which update or deletion of the file is rejected as a Write-Once-Read-Many (WORM) file; and (c) classifying a file written after the mounting as a second group in which update or deletion of the file is permitted as a Read/Write (R/W) file.