Data read/write control system and data read/write control method

• US 20050066112A1
• Filed: 09/16/2004
• Published: 03/24/2005
• Est. Priority Date: 09/19/2003
• Status: Abandoned Application

• Current Assignee: Renesas Electronics Corporation
• Original Assignee: NEC Electronics Corporation (Renesas Electronics Corporation)
• Inventors: Kawaguchi, Hiroyuki, Takahashi, Shuji, Ueda, Yoshitaka, Osakabe, Takeshi
• Application Number:
  US10/942,023
• Publication Number:
  US 20050066112A1
• Time in Patent Office: Days
• US Class Current: 711/103
• CPC Class Codes: G06F 12/0246 in block erasable memory, e.g. flash memory

Abstract

A data read/write control system includes memory divided into a plurality of blocks, a write unit, and a read unit. When writing data to one block of the plurality of blocks, the write unit compares a size of the data with a capacity of a blank area of the block. If the size of the data is larger, the write unit erases all data stored in the block and sequentially writes the data to the block from top or end. If, on the other hand, the size of the data is smaller, the write unit sequentially writes the data to the block from an area next to an area where data is stored. When reading data from the block, the read unit sequentially searches the block from top or end to find an area where data is written last, and reads the data stored in the area.

Claims

1. A data read/write control system comprising:

memory divided into a plurality of blocks;

a write unit for, in writing data to one block of the plurality of blocks, comparing a size of the data with a capacity of a blank area of the block, and, if the size of the data is larger, the write unit erasing all data stored in the block and sequentially writing the data to the block from top or end;

if the size of the data is smaller, the write unit sequentially writing the data to the block from an area next to an area where data is stored; and

a read unit for, in reading data from the block, sequentially searching the block from top or end for an area where data is written last and reading the data stored in the area.

2. The data read/write control system according to claim 1, wherein, in writing data to the block, the write unit further writes control data including information on reading of the data before or after the data.

4. The data read/write control system according to claim 1, further comprising:

a switch unit for, when the write unit writes data to a block, switching a block from which the read unit is to read data to the block where the data is written.

6. The data read/write control system according to claim 1, wherein, if a block becomes full with data, the write unit copies latest data written to the block to a different block and sets a flag indicating that the different block is a valid block for writing and reading data.

8. The data read/write control system according to claim 2, wherein the control data comprises a size of each data written to the block and/or a pointer indicating an address of data written next to each data.

10. The data read/write control system according to claim 2, wherein the control data comprises an address of data written last to the block.

12. The data read/write control system according to claim 1, wherein the write unit verifies the block after writing data to the block.

14. The data read/write control system according to claim 12, wherein, if the verification fails, the write unit overwrites data where the verification fails with data indicating error data.

3. A data read/write control system comprising:

memory divided into a plurality of blocks;

a control data storage unit for storing control data including information on reading of data stored in one block of the plurality of blocks;

a write unit for, in writing data to one block of the plurality of blocks, comparing a size of the data with a capacity of a blank area of the block, and, if the size of the data is larger, the write unit erasing all data stored in the block, sequentially writing the data to the block from top or end, and further writing control data of the written data to the control data storage unit;

if the size of the data is smaller, the write unit sequentially writing the data to the block from an area next to an area where data is stored and further writing control data of the written data to the control data storage unit; and

a read unit for, in reading data from the block, sequentially searching the block for an area where data is written last based on the control data stored in the control data storage unit and reading the data stored in the area.

5. The data read/write control system according to claim 3, further comprising:

a switch unit for, when the write unit writes data to a block, switching a block from which the read unit is to read data to the block where the data is written.

7. The data read/write control system according to claim 3, wherein, if a block becomes full with data, the write unit copies latest data written to the block to a different block and sets a flag indicating that the different block is a valid block for writing and reading data.

9. The data read/write control system according to claim 3, wherein the control data comprises a size of each data written to the block and/or a pointer indicating an address of data written next to each data.

11. The data read/write control system according to claim 3, wherein the control data comprises an address of data written last to the block.

13. The data read/write control system according to claim 3, wherein the write unit verifies the block after writing data to the block.

15. The data read/write control system according to claim 13, wherein, if the verification fails, the write unit overwrites data where the verification fails with data indicating error data.

16. A data read/write control system comprising:

a temporary storage unit for temporarily storing data;

a central processing unit for writing data to the temporary storage unit;

memory divided into a plurality of blocks; and

a control unit having a write unit for, in writing data stored in the temporary storage unit to one block of the plurality of blocks, comparing a size of the data with a capacity of a blank area of the block, and, if the size of the data is larger, the write unit erasing all data stored in the block and sequentially writing the data to the block from top or end;

if the size of the data is smaller, the write unit sequentially writing the data to the block from an area next to an area where data is stored; and

a read unit for, in reading data from the block, sequentially searching the block from top or end for an area where data is written last and reading the data stored in the area.

17. The data read/write control system according to claim 16, wherein, each time data is written to the temporary storage unit, the write unit writes the data to the block.

18. The data read/write control system according to claim 16, wherein the write unit writes data stored in the temporary storage unit to the block upon satisfaction of a predetermined condition.

19. A data read/write control method for controlling data writing and reading in memory divided into a plurality of blocks, the method comprising:

writing data to one block of the plurality of blocks, including comparing a size of the data with a capacity of a blank area of the block, and, if the size of the data is larger, erasing all data stored in the block and sequentially writing the data to the block from top or end;

if the size of the data is smaller, sequentially writing the data to the block from an area next to an area where data is stored; and

reading data from the block, including sequentially searching the block from top or end for an area where data is written last, and reading the data stored in the area.

20. The data read/write control method according to claim 19, wherein, in writing data to the block, control data including information on reading of the data is written before or after the data.

22. The data read/write control method according to claim 19, further comprising predetermining a block where data is to be read, and, if data is written to a block different from the predetermined block, swapping the block where data is written and the block where data is to be read to avoid change in the block where data is to be read.

24. The data read/write control method according to claim 19, further comprising, if a block becomes full with data, copying latest data written to the block to a different block, and setting a flag indicating that the different block is a valid block for writing and reading data.

26. The data read/write control method according to claim 19, wherein the control data comprises a size of each data written to the block and/or a pointer indicating an address of data written next to each data.

28. The data read/write control method according to claim 19, wherein the control data comprises an address of data written last to the block.

30. The data read/write control method according to claim 19, further comprising verifying the block after writing data to the block.

32. The data read/write control method according to claim 30, further comprising, if the verification fails, overwriting data where the verification fails with data indicating error data.

21. A data read/write control method for controlling data writing and reading in memory divided into a plurality of blocks and a control data storage unit for storing control data including information on reading of data stored in one block of the plurality of blocks, the method comprising:

writing data to one block of the plurality of blocks, including comparing a size of the data with a capacity of a blank area of the block, and, if the size of the data is larger, erasing all data stored in the block, sequentially writing the data to the block from top or end, and further writing control data of the written data to the control data storage unit;

if the size of the data is smaller, sequentially writing the data to the block from an area next to an area where data is stored and further writing control data of the written data to the control data storage unit; and

reading data from the block, including sequentially searching the block for an area where data is written last based on the control data stored in the control data storage unit, and reading the data stored in the area.

23. The data read/write control method according to claim 21, further comprising predetermining a block where data is to be read, and, if data is written to a block different from the predetermined block, swapping the block where data is written and the block where data is to be read to avoid change in the block where data is to be read.

25. The data read/write control method according to claim 21, further comprising, if a block becomes full with data, copying latest data written to the block to a different block, and setting a flag indicating that the different block is a valid block for writing and reading data.

27. The data read/write control method according to claim 21, wherein the control data comprises a size of each data written to the block and/or a pointer indicating an address of data written next to each data.

29. The data read/write control method according to claim 21, wherein the control data comprises an address of data written last to the block.

31. The data read/write control method according to claim 21, further comprising verifying the block after writing data to the block.

33. The data read/write control method according to claim 31, further comprising, if the verification fails, overwriting data where the verification fails with data indicating error data.

34. A data read/write control method for controlling data writing and reading in a temporary storage unit for temporarily storing data and memory divided into a plurality of blocks, the method comprising:

writing data to the temporary storage unit;

writing data stored in the temporary storage unit to one block of the plurality of blocks, including comparing a size of the data with a capacity of a blank area of the block, and, if the size of the data is larger, erasing all data stored in the block and sequentially writing the data to the block from top or end;

if the size of the data is smaller, sequentially writing the data to the block from an area next to an area where data is stored; and

reading data from the block, including sequentially searching the block from top or end for an area where data is written last, and reading the data stored in the area.

35. The data read/write control method according to claim 34, wherein, in writing data to one block of the plurality of blocks, data is written to the block each time the data is written to the temporary storage unit.

36. The data read/write control method according to claim 34, wherein, in writing data to one block of the plurality of blocks, data stored in the temporary storage unit is written to the block upon satisfaction of a predetermined condition.

37. Computer-readable media tangibly embodying a program of instructions executable by a computer to perform a method of controlling data writing and reading in a data read/write control system having memory divided into a plurality of blocks, the method comprising:

writing data to one block of the plurality of blocks, including comparing a size of the data with a capacity of a blank area of the block, and, if the size of the data is larger, erasing all data stored in the block and sequentially writing the data to the block from top or end;

if the size of the data is smaller, sequentially writing the data to the block from an area next to an area where data is stored; and

reading data from the block, including sequentially searching the block from top or end for an area where data is written last, and reading the data stored in the area.

38. The computer-readable media according to claim 37, wherein in writing data to the block, control data including information on reading of the data is written before or after the data.

40. The computer-readable media according to claim 37, wherein the method further comprises, upon writing of data to a block, switching a block from which the read unit is to read data to the block where the data is written.

41. The computer-readable media according to claim 37, wherein the method further comprises, if a block becomes full with data, copying latest data written to the block to a different block, and setting a flag indicating that the different block is a valid block for writing and reading data.

42. The computer-readable media according to claim 37, wherein the control data comprises a size of each data written to the block and/or a pointer indicating an address of data written next to each data.

43. The computer-readable media according to claim 37, wherein the control data comprises an address of data written last to the block.

44. The computer-readable media according to claim 37, wherein the method further comprises verifying the block after writing data to the block.

45. The computer-readable media according to claim 44, wherein the method further comprises, if the verification fails, overwriting data where the verification fails with data indicating error data.

48. The computer-readable media according to claim 37, in writing data to one block of the plurality of blocks, data stored in the temporary storage unit is written to the block upon satisfaction of a predetermined condition.

39. Computer-readable media tangibly embodying a program of instructions executable by a computer to perform a method of controlling data writing and reading in a data read/write control system having memory divided into a plurality of blocks and a control data storage unit for storing control data including information on reading of data stored in one block of the plurality of blocks, the method comprising:

writing data to one block of the plurality of blocks, including comparing a size of the data with a capacity of a blank area of the block and, if the size of the data is larger, erasing all data stored in the block, sequentially writing the data to the block from top or end, and further writing control data of the written data to the control data storage unit;

if the size of the data is smaller, sequentially writing the data to the block from an area next to an area where data is stored, and further writing control data of the written data to the control data storage unit; and

reading data from the block, including sequentially searching the block for an area where data is written last based on the control data stored in the control data storage unit, and reading the data stored in the area.

46. Computer-readable media tangibly embodying a program of instructions executable by a computer to perform a method of controlling data writing and reading in a data read/write control system having a temporary storage unit for temporarily storing data and memory divided into a plurality of blocks, the method comprising:

writing data to the temporary storage unit;

writing data stored in the temporary storage unit to one block of the plurality of blocks, including comparing a size of the data with a capacity of a blank area of the block, and, if the size of the data is larger, erasing all data stored in the block and sequentially writing the data to the block from top or end;

if the size of the data is smaller, sequentially writing the data to the block from an area next to an area where data is stored; and

reading data from the block, including sequentially searching the block from top or end for an area where data is written last, and reading the data stored in the area.

47. The computer-readable media according to claim 46, wherein, in writing data to one block of the plurality of blocks, data is written to the block each time data is written to the temporary storage unit.