The Model Of File System Structure Of Smart Card COS Research And Application

With the large-scale application of 3G technology,3G smart card becomes an effective platform for business development, so the demand for smart cards will increase substantially. The BIP channel and multi-application platform of 3G USIM cards provide good conditions for interactive applications, which help to achieve a multi-channel mechanism where multiple applications run simultaneously. In 3G era, mobile phone users can do various kinds of banking or financial business by USIM card. They can also do mobile payment, bank transfer, electronic shopping, electronic purse, and so on, which is much more convenient for users' daily life.The smallest unit Smart Card File System copes with is called a logical block, and the smallest unit it applies for the top application is known as a file. The structure of file system is of great importance to the speed of searching and matching to it. The file system structure includes the physical structure and the logical structure. The main objective of this thesis is to analyse and study the file system structure of smart card based on both of them.Firstly, this thesis has analyzed the structure and principles of several embedded file systems in-depth such as the FAT, JFFS, YAFFS, etc. It does research and comparison in four aspects:the physical storage structure, the memory data structure, file system mount, garbage collection strategy, and so on. It also has analysis and study on the topics of smart card file system storage space as follows:allocation and management, logical structure, file type, file system data structure, the physical characteristics of flash, and so on. This solution to the problem are given.After that, this thesis proposes a structure model of the smart card file system which is in allusion to the physical properties and multi-application requirements for FLASH. This model divides function modules mainly through the file system hierarchy theory, Package the inner function modules, only provides API application interface to the upper layer applications. At the same time it hides the physical characteristics of the underlying hardware by FTL layer, which is more efficient to the management of physical storage space and file content. It improves the efficiency of the file system and the entire COS portability. Then basing on the module partition theory of the smart card file system structure model, it designs a specific file system which is suitable to the multi-application features of USIM. Through the application of USIM card, it is fully proved that the smart card file system can meet the needs of multiple applications and Flash's physical characteristics. It has good stability and compatibility.Finally, it has an analysis and evaluation on the security, stability, scalability of the smart card structure model by the method of scenario-based software architecture. Then the evaluation conclusion is drawn. Through the evaluation method we can check the problems existing in the file system structure model, by improving its performance gradually, its compatibility and stability can be improved.