Syxaw - a Synchronizing XML-aware Mobile File System
                  Tancred Lindholm
   Helsinki Institute for Information Technology
                     ctl@cs.hut.fi

In addition to providing users and applications with the familiar
file-and-directories interface, Syxaw introduces the ability to link
objects (i.e. files and directories) to objects on other devices. Once an
object A is linked to another object B, any changes to A are propagated to
B as soon as possible, and vice versa.  Other than this, A still behaves
like a local file: it can be read and written during network
disconnections and its contents is available at all times.

The key features of Syxaw is support for file synchronization in a weakly
connected environment, optimized data transfer, low overhead on file
system performance, and extended support for XML files. Syxaw
distinguishes itself from other similar file systems, like Coda, by being
fully state-based: even the directory hierarchy is synchronized using
state, rather than by integrating logs of file operations. The state-based
approach simplifies the synchronization protocol and improves file system
performance by not requiring that any change logs are maintained.

Syxaw entails an integrated engine for reconciliation of XML documents. In
addition to being used to integrate changes to the directory hierarchy,
this engine is also available for reconciliation of any XML document
stored in the file system. Since the engine is state-based, applications
need not maintain any change logs to be able to benefit from automatic
reconciliation. In addition to automatic reconciliation, Syxaw also
supports XML by offering optimized storage and access in pre-tokenized
form.