EP0492450A2
Expired / Lapsed
EP
⏱️ 0.0 years remaining
Memory card having an eeprom
Assignee: Fujifilm Holdings Corp
•
Filing: 1991-12-19
•
Granted: —
•
Expires: 2011-12-19
Abstract
Abstract A method of recording data in a memory card using an EEPROM (Electrically Erasable Programmable Read Only Memory). A main memory section (10) has clusters including some idle clusters storing no data therein as distinguished from active clusters storing data therein. When data stored in designated one of the active clusters should be rewritten, a cluster selection control (26) determines whether or not the active cluster of interest has undergone rewriting a predetermined number of times. If the answer of the decision is positive, the cluster control section (26) substitutes the logical address of a particular idle cluster for the logical address of the active cluster to thereby include the idle cluster in the active clusters. Data is written to the idle cluster having turned out an active cluster. Data stored in the cluster replaced by the idle cluster is deleted by a delete signal fed from a system control (32) to thereby serve as an idle cluster. The logical addresses of the clusters and the number of times that the individual clusters have undergone rewriting are stored in a supervisory memory 28 which supervises the main memory section (10).
Inventors
- 👤 Kouichi c/o Fuji Photo Film Co. Ltd. Gouhara
- 👤 Osamu c/o Fuji Photo Film Co. Ltd. Saito
- 👤 Mikio c/o Fuji Photo Film Co. Ltd. Watanabe
- 👤 Satoru c/o Fuji Photo Film Co. Ltd. Okamoto
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-11-05 22:20
CPC Classifications
G; G11; G11C; G11C16/00; G11C16/02; G11C16/06; G11C16/10; G11C16/102; G06; G06Q; G06Q20/00; G06Q20/30; G06Q20/34; G06Q20/341; G07; G07F; G07F7/00; G07F7/08; G07F7/0806; G07F7/0833; G07F7/084; G07F7/10; G07F7/1008
Claims Analysis
Total Claims: 10
Claim 1
Independent Claim
163 words
A method of recording data in a memory card having an EEPROM as a main memory, CHARACTERIZED BY (a) reserving part of a plurality of memory blocks (1- n ) constituting said EEPROM (10) as idle blocks which store no data therein, the other memory blocks being active blocks each storing data therein; (b) determining, when an access of the kind needing rewriting is made to one of said active blocks, how many times said one active block has undergone rewriting; (c) replacing, when said one active block has undergone rewriting a predetermined number of times, the logical address of said one active block and the logical address of particular one of said idle blocks to thereby include said one idle block in said active blocks, while deleting data stored in said one active block and then including said one active block in said idle blocks; and (d) writing said data in said one idle block having been included in said active blocks.
Claim 2
Dependent Claim
93 words
A method in accordance with claim 1, CHARACTERIZED IN THAT step (b) comprises (e) comparing the number of times that said one active block has been undergone rewriting and the number of times said particular idle block has undergone rewriting, step (c) comprising (f) replacing the logical address of said one active block and the logical address of said one idle block if the number of times of rewriting of said one active block is a predetermined number of times greater than the number of times of rewriting of said particular idle block.
Claim 3
Dependent Claim
32 words
A method in accordance with claim 1, CHARACTERIZED IN THAT said particular idle block to replace said one active block is an idle block having undergone rewriting the smallest number of times.
Claim 4
Dependent Claim
51 words
A method in accordance with claim 1, CHARACTERIZED IN THAT even when said one active block has not undergone rewriting said predetermined number of times as determined in step (b), said one active block is replaced with said particular idle block if the data stored in said active block is defective.
Claim 5
Independent Claim
217 words
A method of writing data in a memory card having an EEPROM as a main memory, CHARACTERIZED BY (a) defining in a storage area of said EEPOM (42) a data storage area for writing data and a plurality of headers for storing supervisory information for supervising said data storage area, and providing each of said plurality of headers with a location for storing a particular supervisory number which is to be used when an access for writing data is made to said data storage area; (b) reading, when an access for writing data is made to said data storage area, the supervisory information of one of said headers storing the latest content on the basis of said supervisory number; (c) writing data in said data storage area on the basis of said content of said one header; (d) generating, after said data has been written in said data storage area, the latest supervisory information by changing said supervisory information referenced; (e) selecting, after said latest supervisory information has been generated, another header to be used next on the basis of said supervisory number; and (f) writing said lastest supervisory information generated in step (d) in said header selected in step (e); steps (a) - (f) being repeated to write data while sequentially rewriting said plurality of headers.
Claim 6
Dependent Claim
64 words
A method in accordance with claim 5, CHARACTERIZED BY (g) assigning to said header for storing said latest supervisory information the maximum number produced by adding "1" to the supervisory number of one of said headers to which supervisory information has been written last time; and (h) selecting one of said headers having the minimum supervisory number as a header to be used next.
Claim 7
Dependent Claim
27 words
A method in accordance with claim 5, CHARACTERIZED IN THAT said supervisory numbers are cyclic numbers, said headers being sequentially selected in order of said cyclic number.
Claim 8
Dependent Claim
31 words
A method in accordance with claim 1, CHARACTERIZED IN THAT said supervisory numbers are relative numbers assigned to said headers beforehand, said headers being sequentially used by identifying said relative numbers.
Claim 9
Dependent Claim
387 words
A memory card system using a memory card which incorporates an EEPROM in a main memory section thereof, CHARACTERIZED BY a main memory section (10) comprising said EEPROM having a plurality of memory blocks (1- n ), part of said memory blocks (1- n ) being reserved as idle blocks which store no data therein while the other memory blocks being active blocks each storing data therein; a supervisory memory section (28) storing information representative of a data storage condition, the number of times of data rewriting having occurred, a waiting condition and successful/unsuccessful writing of each of said memory blocks (1- n ) of said main memory section (10) together with logical addresses of said memory blocks; a block selecting section (26) for receiving a logical address sent from an external apparatus to which said memory card is connected and selecting one of said active blocks designated by a logical address matching said logical address from said external apparatus and stored in said supervisory memory section (28); and a system control section (32) for controlling said main memory section (10), said supervisory memory section (28) and said block seclecting section (26) in response to a control signal sent from said external apparatus; said block selecting section (26) comprising: deciding means (200) for reading supervisory information of said active blocks and said idle blocks out of said supervisory memory section and determining whether or not one of said active blocks whose data should be rewritten has undergone rewriting a predetermined number of times; address replacing means (210) for replacing, when said deciding means determines that said one active block has undergone rewriting said predetermined number of times, the logical address of said active block and the logical address of particular one of said idle blocks stored in said supervisory memory section (28) with each other and then writing said replaced logical addresses in said supervisory memory (28); and selecting means (220) for selecting said one idle block having been included in said active blocks by said address replacing means as a memory block to which said logical address sent from said external apparatus is meant; said system control section (32) deleting, when said one active block has the logical address thereof replaced with the logical address of said particular idle block, data stored in said active block.
Claim 10
Dependent Claim
86 words
A system in accordance with claim 9, CHARACTERIZED IN THAT said EEPROM has a storage area in which a plurality of headers storing supervisory information associated with a data storage area are formed, a supervisory number being assigned to each of said plurality of headers for identifying the associated header when data should be written to said data storage area; said system further comprising header supervising means 46 for causing said plurality of headers to be used in sequence on the basis of said supervisory numbers.
References Cited (Backward Citations)
No citation records indexed.
USPTO Annuity & Maintenance Windows
Maintenance schedule is calculated for granted US utility patents.