Patent ID: 7146472

Claim:
A process for modifying data in a card-based transaction system featuring a memory card and a reader capable of reading said card when the latter is located in a position determined in relation to the reader, said card featuring a first RAM memory and a second nonvolatile erasable and re-writable memory, the latter including locations containing data records related to the transactions made by said card, each transaction leading to the modification of at least one of said data locations or the addition of a new record, said process comprising the following steps: a. for a data record to be modified or a record to be added, reading the address of a free location of said second memory in a previous check register located in a first determined location of said second memory, b. writing the new modified or added record in said free location, c. repeating steps a) and b) for each of the records to be modified or added, d. writing, in a second determined location of said second memory, a new check register containing the addresses of the free locations of said second memory to be used in the next transaction, wherein the address of the second determined location is given by said previous check register, and e. erasing said previous check register in said first determined location of said second memory when the transaction is closed and indicating in said new check register that said first determined location is free.