Gemplus Card International

Edouard M Gordons

Francois Geronimi

Charles Coulier

Georges Grimonprez

Microprocessor-based memory card that limits memory accesses by

Method of writing information in a non-volatile memory

The disclosure relates to chip cards and their functioning. When a chip card goes from a first state (A) to a second state (B), functions that were available in the first state are prohibited. To enable the analysis of the malfunctions of the card during a stage of qualification by the testing of an application under real-life experimental conditions, these functions need to be retrieved when a card suffers a malfunction. The invention proposes the placing, in the card, of two state indicators, the first indicator prohibiting the functions that are unnecessary for the step B and the second indicator checking the possibility of making the card return to the step A to retrieve the prohibited functions. The card reader may give the card a command for a return to the state A. This command is verified by the card. If the indicator is in a state that permits the return and if the command is correct, the first indicator is reset in the state corresponding to A. If not, the command is rejected. If the command given is incorrect, the indicator is permanently placed in the state in which it prohibits the return to the State A.

Method for the functioning of a chip card, and chip card in accordance

In a system for the management of non-volatile memories, to avoid losses of information during writing, the critical writing sequences are locked. A back-up information element is stored before the performance of the critical section. The lock is constituted by the bits of the allocation table that designate the location of the saved back-up information. The lock is erased at the end of a normal writing sequence. If there is an abnormal interruption of a writing operation during the critical section, then the lock remains locked. This is detected when the power is turned on again, and the writing is resumed utilizing the saved information elements. The lock and the saved information elements are in a variable zone of the memory, thus preventing memory fatigue in the event of intensive use. Furthermore, the management of the memory is original in that two different memory allocation strategies are used to enable the detection, by the allocation table, of the presence of an information element whose location is not known.

Growing community of inventors

Aubagne, France

Edouard M Gordons