Data storage device and screening method for damaged data columns thereof

Abstract

A data storage device and a method for screening a damaged data column, wherein the data storage device comprises a control unit and a data storage medium, and the data storage medium comprises a plurality of data columns, the control unit performs the method for screening a damaged data column, which comprises: reading the written data of each data column as read data; comparing the read data and the written data of each data column to calculate the average error bit number of each data column; judging whether the average error bit number of each data column is greater than or equal to a default value; and when judging that the average error bit number of a data column is greater than or equal to the default value, recording the data column as a damaged data column; wherein the default value is the average error bit number correctable by an error correction code of the data storage medium. In this way, the problem that the error correction code cannot be corrected or the correction capability is excessively consumed is avoided.

Description

TECHNICAL FIELD

[0001] The present invention relates to a data storage device access technology, and more particularly, to a bad column screening method of a data storage device. BACKGROUND

[0002] Downgrade Flash has a large number of bad columns. When the bad columns are not detected and removed, they will consume most of the error correction code correctable error correction capability (e.g., correctable bit number) of the data storage device, and even exceed the error correction code correctable error correction capability, resulting in lower storage capacity when the data storage device is opened, and easily causing read / write failure of the data storage device. However, if the condition for determining that a data column in the data storage device is a bad column is too strict, the number of bad columns in the data storage device will be too small to exceed the error correction code correctable error correction capability; if the condition for determining that a data column in the data storage device is a bad column is too loose, the number of bad columns in the data storage device will be too large to greatly reduce the error correction code correctable error correction capability. Therefore, a balanced bad column screening method is needed. SUMMARY

[0003] The present invention provides a data storage device and a bad column screening method thereof. The judgment condition of the bad column can be adjusted according to the maximum error bit number supported by the error correction code of the data storage device, so as to avoid the problem of exceeding the error correction code correctable error correction capability or greatly reducing the error correction code correctable error correction capability caused by too strict or too loose judgment condition.

[0004] The bad column screening method provided by the present invention is suitable for a data storage device, wherein the data storage device includes a control unit and a data storage medium, and the data storage medium includes a plurality of data columns. The control unit executes the bad column screening method, which includes: reading the written data of each data column as read data; comparing the read data and the written data of each data column to calculate the average error bit number of each data column; determining whether the average error bit number of each data column is greater than or equal to a default value; and when it is determined that the average error bit number of a data column is greater than or equal to the default value, recording this data column as a bad column; wherein the default value is the average error bit number correctable by an error correction code of the data storage device.

[0005] The data storage device includes a data storage medium and a control unit connected to the data storage medium. The data storage medium includes a plurality of data columns. The control unit is configured to perform a method for screening a damaged data column. The method for screening a damaged data column includes: reading write data of each data column as read data; comparing the read data and the write data of each data column to calculate an average error bit number of each data column; determining whether the average error bit number of each data column is greater than or equal to a default value; and recording a data column as a damaged data column when the average error bit number of the data column is greater than or equal to the default value; wherein the default value is an average error bit number correctable by an error correction code of the data storage device.

[0006] In an embodiment of the present application, the data storage medium includes a plurality of data blocks, each data block includes a plurality of data pages, each data page includes a plurality of data columns in the same row, and the data columns are divided into a plurality of large blocks.

[0007] In an embodiment of the present application, each data page includes a data area and a spare area, and the large blocks are located in the data area.

[0008] In an embodiment of the present application, each large block includes a data area and a spare area.

[0009] The data storage device and the method for screening a damaged data column of the present application can avoid the problem of exceeding the error correction capability of the error correction code or greatly reducing the error correction capability of the error correction code by adjusting the determination condition of the damaged data column according to the maximum error bit number supportable by the error correction code of the data storage device.

[0010] In order to make the above and other purposes, features and advantages of the present application more obvious and easy to understand, the following embodiments are described in detail below, and the accompanying drawings are described as follows. BRIEF DESCRIPTION OF DRAWINGS

[0011] Figure 1 A schematic diagram of a data storage device according to an embodiment of the present application;

[0012] Figure 2 A schematic diagram of a data storage medium according to an embodiment of the present application; and

[0013] Figure 3 A flowchart of a method for screening a damaged data column of a data storage device according to an embodiment of the present application. DETAILED DESCRIPTION

[0014] Please refer to Figure 1This is a schematic diagram of a data storage device provided in an embodiment of the present invention. The data storage device 1 includes a data storage medium 10 and a control unit 20, wherein the control unit 20 is connected to the data storage medium 10 to access data on the data storage medium 10.

[0015] Please refer to Figure 2 This is a schematic diagram of a data storage medium provided in an embodiment of the present invention. This data storage medium 10 includes multiple data blocks (as labeled B0 to BZ-1). Each data block includes multiple data columns 11, and data columns placed in the same row are called data pages (as labeled P0 to PN-1). Furthermore, according to user needs, the data columns 11 can be divided into M chunks (as labeled C0 to CM-1), each chunk C0 to CM-1 containing multiple data columns 11. Z, N, and M in the above are all positive integers. In this embodiment, the data storage medium 10 is implemented using non-volatile memory, such as flash memory, magnetoresistive random access memory, ferroelectric random access memory, or other memory devices with long-term data retention capabilities. Furthermore, in one embodiment, each data page can be divided into a data area and a spare area, and the M chunks are located in the data area. In another embodiment, each block C0 to CM-1 can be divided into a data area and a spare area. The data area is used to store data (or user data), and the spare area is used to store parity check codes, which can be used to correct error bits in the data area.

[0016] Since the corrupted data columns exist within the data storage medium 10, the corrupted data column filtering method of the present invention can effectively identify and record the corrupted data columns of the data storage medium 10 before dividing the data storage medium 10 into a data area and a spare area. After the location of the corrupted data columns is determined, the data area and spare area are then divided. Furthermore, the division of the data area and spare area is based on the logical division of data management; therefore, the user can also first divide the data area and spare area, then use the corrupted data column filtering method of the present invention to identify and record the location of the corrupted data columns, and finally adjust the division of the data area and spare area. The spirit of the two data division methods described above is similar, but the order of execution steps is slightly different. To simplify the description of the present invention, only the second embodiment is described, but it is not limited thereto.

[0017] Please refer to Figure 3This is a flowchart illustrating a method for filtering corrupted data columns in a data storage device according to an embodiment of the present invention. The control unit 20 executes the method for filtering corrupted data columns of the present invention, including the following operations: In step S1, the control unit 20 writes data to all data columns 11 in the data storage medium 10. In step S3, the control unit 20 reads the written data for each data column 11 as read data. In step S5, the control unit 20 compares the read data with the written data for each data column 11 to calculate the average number of error bits for each data column 11. In step S7, the control unit 20 determines whether the average number of error bits for each data column 11 is greater than or equal to a default value, where the default value is the average number of error bits that the error correction code of the data storage device 1 can correct. In step S9, when it is determined that the average number of error bits for a data column 11 is greater than or equal to the default value, the control unit 20 records the data column 11 as a corrupted data column.

[0018] It is worth noting that the size of the spare area in the data storage medium 10 determines the error correction capability of the error correction code. That is, when the spare area in the data storage medium 10 is small, the error correction capability of the error correction code is low, and the number of bits that can be corrected will also be less; when the spare area in the data storage medium 10 is large, the error correction capability of the error correction code is high, and the number of bits that can be corrected will also be more.

[0019] In one example, the data storage medium 10 includes 17472 data columns 11, each with 2560 bits. These data columns are divided into 16 blocks, each containing 1024 data columns 11. Therefore, the spare area has 17472 - (16 * 1024) = 1088 data columns 11, meaning each block can be allocated 68 data columns 11. Thus, the error correction code provides a correction capability of 36 bits for these spare data columns 11. The average number of error bits allowed per data column 11 is 36 / (1024 + 68) = 0.032 bits, which is the default value. Note that these values ​​in this example may change with the size of the data storage medium 10, and the invention is not limited to these values.

[0020] In this example, the control unit 20 writes data to all data columns 11 in the data storage medium 10, reads the written data of each data column 11 as read data, compares the read data and the written data of each data column 11 to calculate the average number of error bits of each data column 11, and determines whether the average number of error bits of each data column 11 is greater than or equal to the default value.

[0021] When the number of error bits in a certain data column 11 is 100 bits, the control unit 20 calculates the average number of error bits in this data column 11 as 100 / 2560 = 0.039 bits. When the control unit 20 determines that the average number of error bits (0.039 bits) in this data column 11 is greater than the default value (0.032 bits), the control unit 20 records this data column 11 as a corrupted data column in a corrupted data column summary table of the data storage device 1.

[0022] When the number of error bits in a certain data column 11 is 70 bits, the control unit 20 calculates the average number of error bits in this data column 11 as 70 / 2560 = 0.027 bits. When the control unit 20 determines that the average number of error bits in this data column 11 (0.027 bits) is less than the default value (0.032 bits), it indicates that this data column 11 is a non-damaged data column.

[0023] It should be noted that the above examples are not intended to limit the present invention. Any person skilled in the art to which this invention pertains can divide the data storage medium 10 into different numbers of large blocks and adjust the size of the data area and the spare area according to the size of the data storage medium 10 and the number of data columns 11. In this way, the error correction capability of the data storage device 1 that can correct errors can be appropriately determined.

[0024] In summary, the data storage device and its method for filtering damaged data columns of the present invention can appropriately adjust the judgment conditions of damaged data columns according to the maximum number of error bits that the error correction code of the data storage device can support. Therefore, it can avoid the problems of exceeding the error correction code's ability to correct errors or the error correction code's ability to correct errors being greatly reduced.

[0025] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention in any way. Although the present invention has been disclosed above with reference to preferred embodiments, it is not intended to limit the present invention. Any person skilled in the art can make some modifications or alterations to the methods and techniques disclosed above without departing from the scope of the present invention to create equivalent embodiments. Any simple modifications, equivalent changes and alterations made to the above embodiments based on the technical essence of the present invention without departing from the scope of the present invention shall still fall within the scope of the present invention.

Claims

1. A method for filtering corrupted data columns, characterized in that, A method for filtering corrupted data columns is applicable to a data storage device, the data storage device including a control unit and a data storage medium, the data storage medium including a plurality of data columns, wherein the control unit performs the following method: Reading the written data for each of these data columns is called reading data; Compare the read data with the write data for each of the data columns to calculate an average number of error bits for each of the data columns; Determine whether the average number of error bits for each of these data columns is greater than or equal to a default value; and When the average number of error bits in a data column is greater than or equal to the default value, the data column is recorded as a corrupted data column. The default value is the average number of error bits that an error correction code of the data storage device can correct.

2. The method for filtering damaged data columns as described in claim 1, characterized in that, The data storage medium includes multiple data blocks, each of which includes multiple data pages, and each of which includes data columns located in the same row, and these data columns are divided into multiple large blocks.

3. The method for filtering damaged data columns as described in claim 2, characterized in that, Each of these data pages includes a data area and a spare area, and the large blocks are located in the data area.

4. The method for filtering damaged data columns as described in claim 2, characterized in that, Each of these large blocks includes a data area and a spare area.

5. A data storage device, characterized in that, include: A data storage medium, comprising multiple data columns; as well as A control unit, connected to the data storage medium, is used to perform a method for filtering corrupted data columns, the filtering method including: Reading the written data for each of these data columns is called reading data; Compare the read data with the write data for each of the data columns to calculate an average number of error bits for each of the data columns; Determine whether the average number of error bits for each of these data columns is greater than or equal to a default value; and When the average number of error bits in a data column is greater than or equal to the default value, the data column is recorded as a corrupted data column. The default value is the average number of error bits that an error correction code of the data storage device can correct.

6. The data storage device as described in claim 5, characterized in that, The data storage medium includes multiple data blocks, each of which includes multiple data pages, and each of which includes data columns located in the same row, and these data columns are divided into multiple large blocks.

7. The data storage device as claimed in claim 6, characterized in that, Each of these data pages includes a data area and a spare area, and the large blocks are located in the data area.

8. The data storage device as claimed in claim 6, characterized in that, Each of these large blocks includes a data area and a spare area.

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