It is object to provide a memory system for reliably detecting an error, if any, in management information that is read out. The same content of telephone number data is stored in memories 8, 9, 10 . When telephone number data is read out of the memories 8, 9, 10 , a comparing section 20 judges if all the contents of the telephone number data are the same. If not, a parity error detecting section 22 performs parity check of the telephone number data and excludes the content from which a parity error is detected as an object not to be processed thereafter. After the parity check, an object-to-be-processed determining section 24 determines whether or not there is any telephone number data in the majority on the basis of the criterion that the sum of the pieces of the telephone number data that is read out. If there is not such telephone number data, it judges that there is an error.
1. A memory system comprising:
memory having three or more areas in which identical management information is stored;
management information reading unit for reading said management information stored in each of said areas;
management information comparing unit for comparing a plurality of pieces of said management information read by said management information reading unit; and
object-to-be-processed determining unit for determining contents that constitute the majority of said plurality of pieces of management information read by said management information reading unit as management information to be processed if the comparison by said management information comparing unit determines that there is a mismatch,
wherein an error detecting code is added to said management information and stored with said management information in said plurality of storage areas; and the memory system comprises a second error detecting unit for performing error detection based on said error detecting code when said management information reading unit reads said plurality of pieces of management information.
2. The memory system according to claim 1 , comprising a third error detecting unit for detecting any error that occurs if the comparison by said management information comparing unit determines that there is a mismatch and no contents of said plurality of pieces of management information read by said management information reading unit constitute the majority of said read plurality of pieces of management information.
3. The memory system according to claim 1 , wherein said management information is a serial number that is unique to an electronic device containing said memory.
4. The memory system according to claim 1 , wherein said management information is identification information that is unique to a user of an electronic device containing said memory.
5. The memory system according to claim 1 , wherein the number of the areas for storing said management information is an odd number.