While MPA mainly focuses on delivering messages, it is important to consider what happens to a message once it arrives at the recipient's device. Most people do not simply throw messages away after reading or hearing them; some people diligently categorize and archive all their messages, while others just let them pile up in an ``inbox.'' Email and voicemail systems currently fulfill this need by allowing users to manage archives of their messages. However, they don't allow users to keep one consistent message archive that may be distributed among multiple devices. Instead, they force users to act as the consistency mechanism between multiple message archives.
We propose a personal distributed file system (DFS) that allows people to locate, access and manage their personal data--including message archives--regardless of where they are or what devices they use.
Multi-user constraints of earlier DFS systems (see Section VI) are relaxed in the personal DFS case. This is because one person is unlikely to be modifying two copies of a file at the exact same time, or at least by nature, avoids doing so.
In a personal DFS, users will have data and files spread over several devices, and should be able to control which subsets are propagated where. Some devices are more resource-poor than others. For example, a palmtop device is unlikely to have the same amount of computational power and storage as a laptop. Therefore, users will want to store or view only a subset of all their personal data on each device.
A persistent mobile data mechanism could be used to synchronize a user's message store, as well as his or her files.
While the personal DFS does not have the multi-user constraints of previous systems, it does present other challenges, because: