US 4,748,320 A · IC card

Abstract

In an IC (integrated circuit) card, a CPU (central processing unit) is connected to a data bus and an address bus. A data memory is connected to the data bus and the address bus. The data memory is a rewritable memory, such as EEPROM (electrically erasable programmable read only memory) or battery backed-up RAM (random access memory). The data memory is segmented into a predetermined number of sectors each consisting of predetermined bytes. An external processing device, such as a terminal device is connected to the data bus and the address bus, via a one-bit I/O line and a port. The terminal device supplies a processing instruction via the I/O line to the third port. The CPU receives the processing instruction via the data bus, analyzes the instruction, and reads out and executes the necessary program. The CPU supplies the results of each processing to the terminal device, by way of the data bus, the port and the I/O bus.

Claims11

Dependent claims

An IC (integrated circuit) card comprising:

rewritable memory means with a plurality of sectors;
and
memory control means for writing into said memory means, data file supplied to the IC card from a processing device outside the IC card, said memory control means including means for chaining a plurality of sectors according to the length of the data file, means for writing chain data of each sector into a predetermined portion of the sector, and means for writing for each data file data relating to the sectors constituting the data file into a predetermined sector.

An IC card comprising:

rewritable memory means including a plurality of chained data sectors constituting a data file, a directory sector for storing data relating to the sectors constituting each data file, a file control sector for storing data relating to said directory sector, each sector having a field for storing data relating to the sector preceding and succeeding to one sector, and the data indicating that the data in the sector is normal;
and
memory control means for reading the data file from said memory means, said memory control means including means for reading out a top sector of the data file, using the directory file and the memory control sector, means for reading out one sector succeeding to and chained with the read-out sector from the data relating to said succeeding sector, means for checking the coincidence and noncoincidence of the data relating to the succeeding sector of said read-out sector with the data relating to the preceding sector of said succeeding sector, and means for correcting, when the check result shows noncoincidence, the data relating to said preceding and succeeding sectors according to the data indicating that the data in the sector is normal.

Dependencies are inferred from the claim text.

IC card

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IC card

Life of this patent

Abstract

Claims11