An External Storage Support for Mobile Applications with Scare Resources

Nowadays, users of mobile phones generate too many files that have to be frequently downloaded to an external storage repository, restricting the user mobility. This paper presents a File Transfer Service (FTS) for mobile phones with scare storage resources. It is a support that can be used through a set of functions (API) that facilitates file transfer between mobile applications and external storage servers, taking advantage of different wireless networks. The FTS selects the best wireless connection (WiFi, GPRS or UMTS) considering accessibility and cost of the service. FTS is able to use the Multimedia Messaging Service (MMS) as an alternative option for transferring files, which is especially useful when the mobile phone connectivity is limited. It is based on the J2ME platform. As a use case, a mobile application named Swapper was built on top of the FTS. When the mobile phone memory runs out, Swapper automatically sends selected files to a web storage server using the best connection available, increasing the storage space in the mobile phone. Swapper includes an efficient replacement policy that minimizes the latency perceived by users.