Research And Implementation Of The EEPPROM Defragmentation On Java Smart Card

Java card is widely used in the highly security fields such as bank， social securityetc. But limited by the hardware resources of the smart card, especially themulti-application smart card is popular, the card’s storage resources has been paid moreand more attention. The implementations and related mechanisms of Java Card virtualmachine are also seriously affecting the efficient of the card. Therefore, it is essential tooptimize the improvement of the card in the storage management. This paper analyzes themanagement methods that Sun Inc. has given of the Java Card’s EEPROM, finds thedisadvantages of the existing methods, and at the last design and implement a newmanagement algorithm that include EEPROM’s defragmentation.The key point is to research the storage management of Java Card’s EEPROM, and toimprove its storage efficiency. Firstly, the Java Card’s write mechanism and EEPROMmanagement are analyzed, that we can find some flaws such as the number of the memoryfragmentation is big, the free space is not continuous, and the storage efficiency is nothigh. Secondly, for the above defects, this thesis redesigned the EEPROM structure thatsome important flag are set in the EEPROM, proposed a new management method thatinclude EEPROM’s defragmentation, and detailed the space allocation, space release theunplug electrical processing in the way. Finally, give the detailed implementation of thenew management algorithm that include EEPROM’s defragmentation, and through the testexperiments, the space allocation and release in the EEPROM can be normal. And afterthe defragmentation, its free pages can all be compacted to the tail of the memory tomaximize the contiguous free space for next storage. The tests indicate that themanagement is feasible and efficient. The result and discussion of simulation and somesuggestions of improving the efficiency of optimizer efficiency are given in the last part.