Distributed file systems have been the focus of much research in the last decades starting with the early proposals [3,13].
Along this line of research, transparency (the fact that the filesystem is not local should be hidden from applications and users) and security have been two main issues. Some systems, like Compaq's Cluster File System[4], do guarantee transparency even in presence of faults, but assume that confidentiality of data and authentication of the parties involved is achieved through some other system. The Andrew File System [6] and CODA [14] instead provide mechanism to authenticate servers over public lines and to ensure that client-server communication could not be eavesdropped. The serious key-management issues arising in such file systems is addressed by the Self-certifying FileSystem [8] (more on SFS in Section 2.3). We do point out that both AFS and CODA assume the server to be trusted and store the data in clear on the server machine. TCFS instead stores the files in encrypted form thus denying the server access to the data in clear.
In this section we review some of the work present in the literature stressing the differences with TCFS either in implementation or in architectural design.