Design Goals

We had several goals in mind when we designed JNFS. First and foremost, the file system client had to run on all network computers. Since a number of vendors are shipping several different types of NCs, it would be ideal to develop a single client that works on all of them. Second, the file system had to provide some form of authentication and access control to ensure that unauthorized users could not gain access to files. In addition, the file server had to be interoperable with other types of file systems, and performance had to be reasonably good. Our implementation of JNFS achieved many of these goals:

• Because the NCRP mandates support of the Java Application Environment [1], a Java implementation of JNFS ensures that it will work on all NC-compliant devices.
• Good security is provided by both an authentication protocol based on digital signatures, and an Access Control List implementation for granting access to files.
• Interoperability with other file systems is provided because JNFS runs on top of a native file system. Thus, JNFS can provide access to files served over both local file systems such as NTFS or a UNIX local file system, as well as network file systems such as NFS or DFS.
• Performance is slower than NFS, but reasonable for a Java application. On average, JNFS file transfers take about 8 times as long as analogous NFS transfers.