Supporting Asynchronous Collaborative Editing in Mobile Computing Environments ∗

Abstract: Mobile computing environments have changed in recent years, with the increasing use of different types of mobile devices and wireless communication technologies. To allow users to store and share their data in this new environment, we are building the Files EveryWhere (FEW) system, that explores the multiple available storage and communication devices to provide good availability and performance. This system is based on optimistic replication and it can be used as a tool for supporting asynchronous collaborative edition, as it al-lows users to cooperate by accessing and modifying shared documents. Our approach is implemented using the file system interface, thus allowing users to continue using their favorite application. In this paper, we focus mainly on the FEW reconciliation mechanism. Our approach is based on operational transformation and it includes several new techniques. First, we propose a new technique for handling operations in oper-ational transformation algorithms that supports efficient epidemic dissemination. Second, we propose a new set of transformation functions that explicitly handle line versions in text files. Finally, we propose a set of transformation functions that explicitly handle file versions for opaque files.