Data storage system for highly frequent repetitive data writing

• US 5,809,556 A
• Filed: 05/14/1993
• Issued: 09/15/1998
• Est. Priority Date: 05/15/1992
• Status: Expired due to Fees

• Current Assignee: Toshiba Corporation
• Original Assignee: Toshiba Corporation
• Inventors: Fujisawa, Akiko, Takahashi, Shinya
• Primary Examiner(s): Chan, Eddie P.
• Assistant Examiner(s): Nguyen, Hiep T.
• Application Number:
  US08/060,831
• Time in Patent Office: 1,950 Days
• Field of Search: 395/400, 395/425, 395/430, 360/53, 369/58, 365/185.11, 365/185.33, 711/103, 711/5, 711/173
• US Class Current: 711/173
• CPC Class Codes: G11C 16/3454 Arrangements for verifying correct programming or for detecting overprogrammed cells
• CPC Class Codes: G11C 16/3459 Circuits or methods to verify correct programming of nonvolatile memory cells
• CPC Class Codes: G11C 29/82 for EEPROMs
• CPC Class Codes: G11C 29/88 with partially good memories
• CPC Class Codes: H04W 88/02 Terminal devices

Abstract

A data storage system has a data storage device comprising an electrically erasable programmable read-only memory which has an array of data storage areas for storing supplied data therein. Supplied data may be written successively in the data storage areas again and again until any one of the data storage areas becomes unusable. Supplied data may also be written repeatedly in each of the data storage areas until each data storage area becomes unusable, and the writing of supplied data may be stopped when all the data storage areas become unusable. Alternatively, supplied data may be written successively in the data storage areas except any one or more of the data storage areas which have become unusable, and the writing of supplied data may be stopped when all the data storage areas become unusable.

Claims

1. A data storage system permitting an increased number of writes, said system comprising:

a data storage device having predetermined areas of data storage locations and performing write, verify, and read operations on said predetermined areas, each of said predetermined areas storing data supplied with a write command, said write command being one of a plurality of write commands issued at different times during the life time of said data storage device;

first means for controlling said data storage device to write data supplied for the first time into a first one of said predetermined areas;

second means, responsive to a determination based on a verify operation that the most recently (or last) supplied data supplied with a last write command was successfully written, for controlling said data storage device to write a next supplied data supplied with a next write command into a next one of the areas of said predetermined areas which experienced a smaller number of write operations than the other areas of said predetermined areas, said second means further comprising;

means for controlling said data storage device to write said next supplied data into said first one of said predetermined areas in response to a further determination that each of said predetermined areas has experienced an identical number of write operations; and

means responsive to a determination based on verify operation that said last supplied data was not successfully written for prohibiting said data storage device from writing.

2. The data storage system according to claim 1 further comprising:

means for defining at least one operation range in the space comprising all of said data storage locations; and

means for defining a plurality of user defined areas in each of said at least one operation range, wherein;

operation of said first and second means is directed to the user defined areas in a specified operation range.

7. The data storage system according to any of claims 1, and 3 further comprising:

means for setting a part of said each data storage area for a target of said verify operation.

3. A data storage system permitting an increased number of writes, said system comprising:

a data storage device having predetermined areas of data storage locations and performing write, verify, and read operations on said predetermined areas, each of said predetermined areas storing data supplied with a write command, said write command being one of a plurality of write commands issued at different times during the life time of said data storage device;

first means for controlling said data storage device to write data supplied for the first time into a first one of said predetermined areas;

second means, responsive to a first determination based on a verify operation that the last supplied data supplied with the last write command was successfully written, for controlling said data storage device to write a next supplied data supplied with a next write command into a following one of a usable area of said predetermined areas which experienced a smaller number of write operations than the other usable areas of said predetermined areas; and

third means, responsive to a second determination based on said verify operation that said last supplied data was not successfully written for controlling said storage device to write said last supplied data into a following one of the usable areas of said predetermined areas which experienced a smaller number of write operations than other usable predetermined areas, wherein;

said second and third means are responsive to a further determination that each of said usable predetermined areas have experienced an identical number of write operations for controlling said device to write said next supplied data into said first one of said usable predetermined areas.

4. The data storage system according to claim 3 wherein:

said third means includes means, responsive to a determination that all of said predetermined areas have become unusable, for prohibiting said data storage device from writing.

5. The data storage system according to claim 3, further comprising:

means for defining at least one operation range in the space comprising all of said storage areas locations; and

means for defining a plurality of user defined areas in each of said at least one operation range, wherein;

operation of said first, second, and third means is directed to the user defined areas in a specified operation range.

6. The data storage system according to claim 3 wherein said third means includes means for storing information on the area where said last supplied data was not successfully written;

and

said second and third means utilize said information for said controlling.

8. A method of increasing the number of possible write operations in a system including a data storage device having predetermined areas of data storage locations and performing write, verify, and read operations on said predetermined areas, each of said predetermined areas storing data supplied with a write command, said write command being one of write commands issued during the life time of said data storage device, said method comprising the steps of:

(a) writing data supplied for the first time into a first one of said predetermined areas; and

(b) in response to a determination based on a verify operation that the last supplied data supplied with a last write command was successfully written, writing a next supplied data supplied with a next write command in a next one of the areas of said predetermined areas which experienced a smaller number of write operations than the other areas of said predetermined areas

wherein;

step (b) includes the step of;

in response to a further determination that each of said predetermined areas has experienced an identical number of write operations, writing said next supplied data into said first one of said predetermined areas; and

said method further includes the step of;

in response to a determination based on said verify operation that said last supplied data was not successfully written, performing no more write operations.

9. A method of increasing the number of possible write operations in a system including a data storage device having predetermined areas of data storage locations and performing write, verify, and read operations on said predetermined areas, each of said predetermined areas storing data supplied with a write command, said write command being one of write commands issued during the life time of said data storage device, said method comprising the steps of:

(a) writing data supplied for the first time into a first one of said predetermined areas; and

(b) in response to a determination based on a verify operation that the last supplied data supplied with a last write command was successfully written, writing a next supplied data supplied with a next write command into a following one of a usable area of said predetermined areas which experienced a smaller number of write operations than the other usable predetermined areas

(c) in response to a determination based on said verify operation that said last supplied data was not successfully written, writing said last supplied data into a following one of the usable areas of said predetermined areas which experienced a smaller number of write operations than other usable predetermined areas,

wherein steps (b) and (c) include the step of;

(d) in response to a determination that each of said usable predetermined areas have experienced an identical number of write operations, writing said next supplied data into said first one of said usable predetermined areas.

10. The method according to claim 9 further comprising the step of:

(e) in response to a determination based on said verify operation that all of said predetermined areas have become unusable, performing no more write operations.

11. The method according to claim 10 wherein step (c) includes the step of:

storing up information on the unusable area where said last supplied data was not successfully written and

steps (b), (c) and (e) include the step of;

in said writing, utilizing said information for a determination of whether said predetermined area associated with said writing is usable or not.

12. A radio communication apparatus for use in a radio communication system wherein signals are transmitted from a communication station to said apparatus over radio links, said apparatus comprising:

receiving means for receiving a plurality of signals carrying respective data and separately transmitted at different times from said communication station over said radio links;

storing means having a plurality of areas of data storage locations permitting write, verify, and read operations, said each area storing data transmitted by one of said plurality of signals received by said receiving means;

first means for controlling said storing means to write data received for the first time by said apparatus into a first one of said plurality of areas; and

second means, responsive to a determination based on said verify operation that the last supplied data supplied by the last signal was successfully written, for controlling said storing means to write a next supplied data supplied by a next signal into a next one of the storage areas which experienced a smaller number of write operations than other of said areas, and

said second means responsive to a further determination that each of said plurality of storage areas has experienced an identical number of write operations for controlling said storing means to write said next supplied data into said first one of said plurality of areas, said second means including;

means, responsive to a determination based on said verify operation that said supplied data was not successfully written, for instructing said storing means to perform no more write operations.

13. A radio communication apparatus for use in a radio communication system wherein signals are transmitted from a communication station to said apparatus over radio links, said apparatus comprising:

receiving means for receiving a plurality of signals carrying respective data and separately transmitted at different times from said communication station over said radio links;

storing means having a plurality of areas of data storage locations permitting write, verify, and read operations, said each area storing data transmitted by one of said plurality of signals received by said receiving means;

first means for controlling said storing means to write data received for the first time by said apparatus into a first one of said plurality of areas; and

second means, responsive to a determination based on said verify operation that the last supplied data supplied by the last signal was successfully written, for controlling said storing means to write a next supplied data supplied by a next signal into a following one of the usable areas of said storage areas which experienced a smaller number of write operations than the other usable areas, and

said second means responsive to a determination based on said verify operation that said last supplied data was not successfully written, for controlling said storing means to write said last supplied data into a following one of the usable areas among said storage areas which experienced a fewer number of write operations than the other usable areas, said second means including;

means, responsive to a further determination that each usable area of said plurality of areas have experienced an identical number of write operations for controlling said storing means to write said next supplied data into said first one of said usable areas.

14. A radio communication apparatus for use in a radio communication system wherein said apparatus communicates with a communication station over radio links, said apparatus comprising:

a data source for providing a plurality of data transmissions at such time intervals that data provided by said data transmissions are written by different write operations;

storing means having a plurality of areas of data storage locations permitting write, verify, and read operations, said each area storing data supplied by one of said data transmissions provided by said data source;

first means for controlling said storing means to write data supplied by a first data transmission to said storing means into a first one of said plurality of areas; and

second means, responsive to a determination based on a verify operation that the last data supplied by a last data transmission was successfully written, for controlling said storing means to write a next supplied data supplied by a next data transmission into a next one of said storage areas which experienced a smaller number of write operations than the other usable areas of said storage areas, and

said second means responsive to a further determination that each of said plurality of storage areas has experienced an identical number of write operations, for controlling said storing means to write said next supplied data into said first one of said plurality of areas, said second means including;

means, responsive to a determination based on said verify operation that said last supplied data was not successfully written, for instructing said storing means to perform no more write operations.

15. A radio communication apparatus for use in a radio communication system wherein said apparatus communicates with a communication station over radio links, said apparatus comprising:

a data source for providing a plurality of data supplies at such time intervals that data provided by said data supplies are written by different write operations;

storing means having a plurality of areas of data storage locations permitting write, verify, and read operations, said each area storing data supplied by one of said data supplies provided by said data source;

first means for controlling said storing means to write data supplied by the first data supply to said storing means into a first one of said plurality of areas; and

second means responsive to a determination based on verify operation that the last supplied data supplied by the last data supply was successfully written for controlling said storing means to write the next supplied data supplied by the next data supply into a following one of the usable storage areas which experienced a smaller number of write operations than the other usable areas, and responsive to a determination based on said verify operation that said last supplied data was not successfully written for controlling said storing means to write said last supplied data into a following one of the usable storage areas which experienced a fewer number of write operations than the other usable areas, said second means including;

means responsive to a further determination that each of all the usable areas of said plurality of storage areas have experienced an identical number of write operations for controlling said storing means to write said next supplied data into said first one of said usable areas.