Information recording medium

Abstract: In an information recording medium including a memory section (1) for storing therein information inputted from an external apparatus, information generated internally on the basis of the inputted information, or converted information, a computing and processing section for performing control to write the above described information into the memory section, and a program storage sectioh for storing therein control programs such as control program and write control program required for the computing and processing section to transfer/receive information to/from the external apparatus, a recording scheme for information recording medium wherein at least one of the memory section and the program storage section comprises a fixed item information recording area (3) having predetermined recording contents, information pieces (5-13) with an error detection information piece (2) added per information item being stored into the fixed item information storage area, and a variable item information storage area (4) selected as occasion demands, information (14) with an error detection information piece (2) added per preset information length being stored into the variable item information storage area.

Description: The present invention relates to a recording scheme for information recording medium, and in particular to such improvement of an IC card that information may be efficiently stored into a memory. Description of the Prior Art Owing to high density packaging techniques and the like in recent years, respective memory devices have large storage capacities. However, there is a limit in the number of memory devices which can be mounted on an information recording medium such as an IC card. Storage of a larger amount of information and more functions than before are demanded. The amount of information stored thus increases steadily. Information stored in a memory portion of an information recording medium such as an IC card is classified broadly into information which should be necessarily recorded on each IC card (fixed item information), information selectively recorded according to the purpose or application, and information arbitrarily recorded (variable item information). In an information recording scheme for IC card, a memory section for storing therein data or program is divided into records respectively having fixed information lengths, and information inputting/outputting and error detection of recorded information are performed while taking a record as unit. In another information recording scheme, an arbitrary length is chosen to be a record according to the length of information recorded in the memory section, and information having variable length is accordingly stored, inputted and outputted. In this case, error detection of recorded information is performed while taking the variable record as unit. In the former case, error detection of recorded information can be performed easily. If the record length is detected and error detection of information recorded in the record is performed, however, areas of the memory section are unadvantageously wasted. On the other hand, the latter case has a drawback that error detection information increases in amount and the efficiency of use of the memory portion is lowered when the record length is extremely short because error detection information for performing error detection of recorded information is added to each record. Fig. 1 shows an example of a memory map of such prior art used in an IC card. No prepublished document corresponding to this prior art is available. A fixed item information storage area 3 and a variable item information storage area 4 are provided. Fixed item information and variable item information are continuously stored in respective storage areas. And error detection information is inserted at intervals of fixed length. Assuming now that the recording information length (word length) of a memory 1 per line is 32 bytes, fixed item information pieces 5 to 13 are handled while taking 32 bytes as unit irrespective of the length of the information piece, and error detection information 2 is recorded at the last position of 32-byte word. Therefore, each of the fixed term information pieces of data 7 and 9 is divided into two parts by the error detection information and relates to two error detection information pieces of data. It is now assumed that an error is caused in the fixed item information 5, which has been recorded, such as a secret identification number. The error is detected from the error detection information 2 of the fixed item information (secret identification number). Since the pertinent error detection information is common to the fixed term information 6 and the fixed term information 7, however, these are also judged erroneous and so processed. On the other hand, transaction history information 14 stored in the variable item information storage area 4 differ in information length of one information unit and the number of information units is determined according to the purpose and application. Accordingly, there occurs a difference in the recording efficiency of memory among IC cards which are different in purpose and application. The efficiency is thus lowered according to the purpose and application. Any information stored in the fixed item information storage area 3 is very important to the operation of the IC card. An object of the present invention is to provide a recording scheme for information recording medium whereby a problem of lowered use efficiency of the memory section caused in an IC card of the prior art by recording error detection information is overcome and an information recording medium is obtained having a high recording efficiency and a high error detection and processing efficiency. US-A-4 797 543 discloses an information medium which has the abovementioned problem that error detection data is not provided in the most efficient manner. In accordance with the present invention, error detection information for recorded information is added to each piece of information data of fixed item information (such as the name and secret identification number of a processor), and error detection information for more general variable recorded information is added to latter variable item information (such as transactions history information) with a piece of error detection information for each preset length of such variable item information. In one aspect of the invention as defined in claim 1, the pieces of error detection information data for the variable item information data are each added after a respective preset length of such variable item information data. In another aspect of the invention as defined in claim 2, the pieces of error detection information data for the preset lengths of variable item information data are stored in a separate error detection information storage area. Since the items of fixed item information are predetermined, the amount of its recorded information for each item can be grasped beforehand. Even if error detection information is added to the fixed item area, it is possible to perform recording without waste and its error detection processing can be carried out efficiently. In variable items, selected pieces of information differ depending upon the purpose and application, and the length of the piece of information and its contents differ depending upon the item. For such variable item information, information is recorded while adding pieces of error detection information data for recorded information at intervals of preset lengths of the variable item information. As a result, error detection information and variable item information can be recorded with minimal waste, regardless of whether the pieces of error detection data are each provided with the variable item information data to which it relates or are provided in a separate error detection information storage area. While WO 87/07060, which is only relevant under Article 54(3) EPC, discloses an IC card quite similar to the subject matter of the present invention, it fails to provide the arrangements for recording error detection information data in the manner required by the present invention to provide recording with minimum waste. BRIEF DESCRIPTION OF THE DRAWINGS Fig. 1 is a schematic view of a memory map showing an example of an IC card of the prior art. Figs. 2 and 3 are schematic views of memory maps of embodiments wherein the recording scheme for information recording medium according to the present invention are applied to IC cards. DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will now be described in detail by referring to drawings. Figs. 2 and 3 are schematic views of memory maps of embodiments wherein the recording scheme for information recording medium according to the present invention are applied to IC cards. Numeral 1 denotes a memory of an IC card, whereto a microprocessor (not illustrated) gains access to write/read information. The microprocessor transfers/receives information to/from an external apparatus such as a reader-writer with an IC card inserted thereon or a host computer via an interface (not illustrated) and stores information inputted from an external apparatus or information generated internally or converted internally according to the inputted information into the memory 1. By taking cashless shopping using an IC card as an example, contents of recorded information in the memory 1 is shown in Fig. 2. The memory 1 is divided into a fixed item information storage area 3 and a variable item storage area 4. The area of the fixed item information storage area 3 is defined on the basis of calculation of the amount of the fixed items used, and the remaining area is allotted to the variable item information. In Fig. 2, it is assumed that three kinds of secret identification number are used in a card and three secret identification numbers are allotted to the beginning of the fixed item information storage area 3. These are secret identification number (ID₁) 5, secret identification number (ID₂) 6 and secret identification number (ID₃) 7. Error detection information 2 is added to the end position of each of these three secret identification numbers. After these three secret identification numbers, a secret identification number noncoincidence count recording area (CONT) 8 is secured. The error detection information 2 is added to the last position of the secret identification number noncoincidence count recording area (CONT) 8 as well. An information piece recorded as the next fixed item is herein a possessor's name (NAME) 9. Succeedingly, a card possessor's address (ADD) 10, a card possessor's telephone number (TEL) 11, a card classification 12, and issue date 13 are recorded one after another. Error detection information 2 is added at the last position of each of these fixed item information pieces as well. These fixed item information pieces are indispensable to respective IC cards and nearly common to any IC cards. These are defined beforehand and the length of them are already known. The order of the recording arrangement of these fixed item information pieces are not fixed, but selected for respective cards. Unlike the fixed item information, variable item information represented by transactions history information 14 often differs in recording format depending upon purpose and application. Concrete examples of this transactions history information 14 are transactions history information in a retail store A, transactions history information in a retail store B, and deposited amount in a bank A. These transactions history information pieces 14 are not constant in length. Therefore, error detection information 2 is inserted at intervals of constant length, say, 32 bytes and the last position of each interval (such as the illustrated rightmost position of the memory 1). When an IC card is used and the possessor's name (NAME) 9, for example, is to be read out, it is read out after the competence to readout of the pertinent area has been checked. The microprocessor which is the processing portion of the IC card also reads out the error detection information 2 concurrently with readout of the possessor's name (NAME) from the memory 1. The microprocessor then performs error detection processing of recorded information by using the error detection information 2 and thereafter sends out the information read out to an external apparatus. If an information error is caused in the recorded secret identification number (ID₁) 5 under the present recording scheme, the error is detected from the error detection information 2 of the secret identification number (ID₁) 5. Since in this case the pertinent error detection information is common neither to the secret identification number (ID₁) 6 nor to the secret identification number (ID₁) 7, these are not judged erroneous unlike the prior art described before by referring to Fig. 1. As for the transactions history information 14, error detection information 2 is added at intervals of preset information length, say, 32 bytes in order to perform the addition of error detection information independently of recording length. When a certain piece of information has been manipulated in this case, it is always necessary to renew and rerecord a single error detection information piece 2 or a plurality of error detection information pieces 2 pertinent to the manipulated information. In an embodiment illustrated in Fig. 3, an error detection information storage area 15 for storing therein only error detection information 2 is provided, and error detection information pieces 2 for transactions history information pieces 14 illustrated in Fig. 2 are concentrated to the area 15 as shown in Fig. 3. Embodiments have heretofore been described laying stress on a memory for storing data therein. As a matter of course, however, the present invention is similarly applicable to a memory for storing program in which fixed item information or the like is stored. Embodiments have heretofore been described laying stress on an IC card. As a matter of course, however, the present invention is applicable to various information storage media such as another memory card incorporating a microprocessor therein and a memory cartridge. In accordance with the present invention heretofore described, error detection information for recorded information is added to each information item for fixed item information indispensable to an IC card and added at intervals of preset information length for variable item information which is variable according to the purpose and application of the IC card. Without depending upon the purpose and application of the IC card, therefore, constant recording efficiency can always be maintained and error detection processing can be efficiently performed.

Claims: An information recording medium, e.g. an IC card, including: a memory section (1) for storing therein information input from an external apparatus, information generated internally on the basis of the input information, or converted information; a computing and processing section for controlling the writing of the abovedescribed information into said memory section; and a program storage section for storing therein control programs such as control and write control programs required for said computing and processing section to transfer/receive information to/from said external apparatus, the contents of at least one of said memory section (1) and said program storage section comprising: a fixed item information recording area (3) for recording fixed information which is always to be recorded on said medium; said area comprising a plurality of pieces of fixed information data (5-13) each piece having a respective predetermined length; and further comprising a plurality of pieces of error detection information data (2) each piece respectively provided for each piece of fixed information data stored in said fixed item information recording area; and a variable item information storage area (4) for storing variable item information data (14) which is selectively or arbitrarily recorded; said area comprising a plurality of fields of a common and predetermined length, each field being for storing therein a part of said variable item information data together with a corresponding piece of error detection information data corresponding thereto. An information recording medium, e.g. an IC card, including: a memory section (1) for storing therein information input from an external apparatus, information generated internally on the basis of the input information, or converted information; a computing and processing section for controlling the writing of the abovedescribed information into said memory section; and a program storage section for storing therein control programs such as control and write control programs required for said computing and processing section to transfer/receive information to/from said external apparatus, the contents of at least one of said memory section and said program storage section comprising: a fixed item information recording area (3) for recording fixed information which is always recorded on said medium; said area comprising a plurality of pieces of fixed information data (5-11), each piece having a respective predetermined length; and further comprising a plurality of pieces of error detection information data (2) each piece being respectively provided for each piece of fixed information data stored in said fixed item information recording area; and a variable item information storage area (4) for storing variable item information data (14) which is to be selectively or arbitrarily recorded; said area comprising a plurality of fields of a common and predetermined length, each field being for storing therein a piece of said variable item information data; and an error detection information storage area (15) for storing therein pieces of error detection information data (2), each piece of error information data respectively relating to a field of said variable item information data. A recording medium according to claim 1, wherein the piece of error detection information data for each piece of fixed or variable information data is recorded at the tail of the respective piece of said information data. A recording medium according to any preceding claim, wherein said predetermined record length is 32 bytes.

Inventors: SHINAGAWA TOHRU, SHINAGAWA, TOHRU
Applicants: HITACHI MAXELL, HITACHI MAXELL LTD.
Application year: 1988
Main classification: G06K19
IPC codes: G07F7, G06F12, G06K17, G06K19