Mobile Applications Middleware for File Swapping

Intelligent mobile phones (e.g. smartphones) integrate the functions of PDA (Personal Digital Assistant) in conventional mobile phones. These technologic developments allow them to run applications that generate a large number of files and, as a consequence, require a greater storage capacity. Unfortunately, the storage capacity on these devices has not grown at the pace that mobile applications require. Keeping files in external servers becomes a typical requierement for these type of devices. This paper presents a mobile application midlleware for file swapping. This middleware makes easier transfering files between a mobile device and an external storage server by accessing the best wireless connection (WiFi, GPRS/UMTS) available, considering quality and cost of the service. It is also able to use the Multimedia Messaging Service (MMS) as another option for transferring files. A file swapping application was built on top of this Middleware. This application will detect when the device ran out of local memory and will automatically send selected files from the mobile device to an external storage server, freeing the mobile storage memory. To decide which files should be backed up, it implements several file replacement policies. Results showed that the selection of one replacement policy will be a trade-off between the efficiency of the algorithm and the cost of the wireless service available when a file needs to be backed up.