A new one-way isolation file-access method at the granularity of a disk-block

In this paper, we propose a file-access method, called as OIDB(One-way Isolation Disk Block), which always keeps original files on pristine status and enables users to access files without restricting the functionality. This is accomplished via one-way isolation: users can read files in origin storage, but they are not permitted to write files in the origin storage. Their writing operations are redirected to the temporary storage. A key property of our approach is that files are accessed at the granularity of a disk-block, which makes the overheads of disk-block copying be alleviated largely. OIDB supports a wide range of tasks, including: sharing pristine data, supporting file system versioning, testing unauthentic software. The employment of OIDB in TransCom System has verified its desirable features. The performance evaluation represents that OIDB introduces low disk-block copying overheads in the process of accessing a file, especially in modifying a file.