Accessing Files on Unmounted Filesystems

This paper describes a utility named ruf that reads files from an unmounted file system. The files are accessed by reading disk structures directly so the program is peculiar to the specific file system employed. The current implementation supports the *BSD FFS, SunOS/Solaris UFS, HPUX HFS, and Linux ext2fs file systems. All these file systems derive from the original FFS, but have peculiar differences in their specific implementations. The utility can read files from a damaged file system. Since the utility attempts to read only those structures it requires, damaged areas of the disk can be avoided. Files can be accessed by their inode number alone, bypassing damage to structures above it in the directory hierarchy. The functions of the utility is available in a library named libruf. The utility and library is available under the BSD license.