Communications in locally structured wireless networks, such as ad hoc networks, will play an important role for network services and applications in the ubiquitous networking environments of the future. Most of the time, however, mobile networks are used in much the same way as fixed networks: most of the time, mobile terminals merely access information which is stored in the backbone network. Applications based on the local exchange of information gathered or generated by mobile terminals will open up many novel possibilities. A new online storage system named CAOSS facilitates such exchange and constitutes a building block for various new applications. CAOSS is a server-less system that provides high availability of data in mobile and wireless network environments. We describe CAOSS and its application in a mobile video-information-sharing system named GT. Thanks to the good performance of CAOSS, the GT system gives users a convenient and easy way to share and accumulate video data in a wireless environment. We confirm that CAOSS has strong enough performance to deal with large volumes of video data.

Data Replication can be used to improve the system availability of distributed systems. In such a system, a mechanism is required to maintain the consistency of the replicated data. The grid structure technique based on quorum is one of the solutions to perform this while providing a high availability of the system. It was shown in the study that, it still requires a bigger number of copies be made available to construct a quorum. So it is not suitable for large systems. In this paper, we propose a technique called the neighbor replication on grid (NRG) technique by considering only neighbors to have the replicated data. In comparison to the grid structure technique, NRG requires a lower communication cost for an operation, while providing a higher system availability, which is preferred for large systems.