Abstract: Microprocessor-based cards use application programs contained in a non-volatile user memory (MU), under the control of an operating system in a read-only memory (MSYS). To provide flexibility and security of access to the various memory zones without using a specific rigidly fixed circuitry, it is proposed that the memory access instructions of the application programs (PG1, PG2, PG3) should be interpreted and not performed directly. The interpreter is in the read-only memory (MSYS) or in the user memory and it carries out an access instruction as follows: it explores a reserved zone (ZR) of the user memory to find out if the requested access (access for reading, writing or performance) is cleared for the requested address. It performs the instruction only if the clearance is present. The reserved zone (ZR) which contains these clearances is updated during the writing, in the user memory, of a new application program. The updating can be done only by the operating system.

Abstract: Non-volatile memory cards in which the writing mechanisms are controlled by a microprocessor.To improve the coherence of the data elements recorded in the non-volatile memory files, the invention proposes to provide for a possibility of grouped control of several write operations (addition, updating or elimination of recordings). The successive operations are performed by the recording, in a non-volatile transaction space (TS), of the data elements corresponding to the state of the memory before each operation (especially former chainings (A7/16) of chained recordings). Then, a command for the comprehensive validation of the N operations, or on the contrary a command for comprehensive invalidation, is carried out, a validation or invalidation of individual operations being not permitted.

Abstract: 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.