Java智能卡EEPROM碎片整理算法研究及实现
发布时间：2018-09-13 16:19
【摘要】：Java智能卡已经逐渐被广泛应用于银行、通信等安全性要求很高的领域中。但是受限于当前智能卡的硬件资源，特别是多应用智能卡的流行，卡片的存储资源越来越受到重视，Java卡虚拟机的具体实现方式和相关机制也严重影响了卡片的执行效率。因此，对卡片中得存储管理进行优化改进是十分必要的。在分析了Sun公司给出的Java卡EEPROM的管理算法之后，总结出现有算法的缺陷，，提出了一种带碎片整理的EEPROM管理算法。 研究Java卡EEPROM的存储管理方式，对存储方式改进，能提高其存储效率。首先通过分析Java卡的写操作机制以及Sun公司的Java卡参考实现中EEPROM管理方式，发现其存在存储碎片多，空闲空间不连续，存储效率不高等缺陷。然后针对上述的缺陷对EEPROM的结构重新设计，在EEPROM的结构中设置了一些重要的标志位，提出一种带碎片整理的存储管理方式，详细叙述此方式下的空间分配、空间释放算法以及放拔掉电处理。最后给出了这种带碎片整理的EEPROM管理算法的实现，通过相关实验测试，EEPROM的空间分配、释放都能正常进行，并且在EEPROM完成碎片整理后，其空闲页都能有效的紧凑到存储器的尾部，为下次的存储提供最大化的连续空闲空间，表明此EEPROM的管理方式是高效可行的，并提出了一些进一步改进效率的建议和展望。
[Abstract]:Java smart card has been widely used in banks, communications and other areas with high security requirements. However, limited by the current smart card hardware resources, especially the popularity of multi-application smart cards, more and more attention has been paid to the memory resources of cards, the implementation of Java card virtual machines and related mechanisms have also seriously affected the efficiency of card execution. Therefore, it is necessary to optimize the storage management in cards. After analyzing the management algorithm of Java card EEPROM proposed by Sun Company, this paper summarizes the defects of the algorithm, and puts forward a EEPROM management algorithm with defragmentation. The storage management mode of Java card EEPROM is studied. The storage efficiency can be improved by improving the storage mode. Firstly, by analyzing the writing operation mechanism of Java card and the EEPROM management mode in the Java card reference implementation of Sun Company, it is found that there are many defects such as more storage fragments, discontinuous free space and low storage efficiency. Then, aiming at the defects mentioned above, the structure of EEPROM is redesigned, and some important flag bits are set up in the structure of EEPROM. A storage management method with defragmentation is proposed, and the space allocation under this mode is described in detail. Space release algorithm and discharge unplug processing. Finally, the implementation of this EEPROM management algorithm with defragmentation is given. The space allocation of EEPROM is tested by relevant experiments, the release can be carried out normally, and after EEPROM defragmentation, its free pages can be effectively compact to the end of memory. It shows that the management method of this EEPROM is efficient and feasible, and puts forward some suggestions and prospects for further improving the efficiency.
【学位授予单位】：华中科技大学
【学位级别】：硕士
【学位授予年份】：2013
【分类号】：TP333
[Abstract]:Java smart card has been widely used in banks, communications and other areas with high security requirements. However, limited by the current smart card hardware resources, especially the popularity of multi-application smart cards, more and more attention has been paid to the memory resources of cards, the implementation of Java card virtual machines and related mechanisms have also seriously affected the efficiency of card execution. Therefore, it is necessary to optimize the storage management in cards. After analyzing the management algorithm of Java card EEPROM proposed by Sun Company, this paper summarizes the defects of the algorithm, and puts forward a EEPROM management algorithm with defragmentation. The storage management mode of Java card EEPROM is studied. The storage efficiency can be improved by improving the storage mode. Firstly, by analyzing the writing operation mechanism of Java card and the EEPROM management mode in the Java card reference implementation of Sun Company, it is found that there are many defects such as more storage fragments, discontinuous free space and low storage efficiency. Then, aiming at the defects mentioned above, the structure of EEPROM is redesigned, and some important flag bits are set up in the structure of EEPROM. A storage management method with defragmentation is proposed, and the space allocation under this mode is described in detail. Space release algorithm and discharge unplug processing. Finally, the implementation of this EEPROM management algorithm with defragmentation is given. The space allocation of EEPROM is tested by relevant experiments, the release can be carried out normally, and after EEPROM defragmentation, its free pages can be effectively compact to the end of memory. It shows that the management method of this EEPROM is efficient and feasible, and puts forward some suggestions and prospects for further improving the efficiency.
【学位授予单位】：华中科技大学
【学位级别】：硕士
【学位授予年份】：2013
【分类号】：TP333
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