Memory management method, memory storage device and memory controlling circuit unit

• US 10,459,630 B2
• Filed: 10/21/2014
• Issued: 10/29/2019
• Est. Priority Date: 08/25/2014
• Status: Active Grant

• Current Assignee: Phison Electronics Corporation
• Original Assignee: Phison Electronics Corporation
• Inventors: Yeh, Chih-Kang
• Primary Examiner(s): Khan, Masud K
• Application Number:
  US14/519,138
• Publication Number:
  US 20160054921A1
• Time in Patent Office: 1,834 Days
• CPC Class Codes: G06F 11/10 Adding special bits or symbols to the coded information, e.g. parity check, casting out 9's or 11's
• CPC Class Codes: G06F 11/1048 using arrangements adapted for a specific error detection or correction feature
• CPC Class Codes: G06F 2211/007 Encryption, En-/decode, En-/decipher, En-/decypher, Scramble, (De-)compress
• CPC Class Codes: G06F 2212/401 Compressed data
• CPC Class Codes: G06F 2212/402 Encrypted data
• CPC Class Codes: G06F 3/0604 Improving or facilitating administration, e.g. storage management
• CPC Class Codes: G06F 3/0659 Command handling arrangements, e.g. command buffers, queues, command scheduling
• CPC Class Codes: G06F 3/0683 Plurality of storage devices

Abstract

A memory management method, a memory storage device and a memory controlling circuit unit are provided. The method includes: defining a first data management rule for a first type physical unit and a second data management rule for a second type physical unit, and a data density of the first type physical unit is lower than the data density of the second type physical unit; if a first physical unit belongs to the first type physical unit, managing the first physical unit according to the first data management rule to make the data stored in the first physical unit conforming to a first reliability level; and if the first physical unit belongs to the second type physical unit, managing the first physical unit according to the second data management rule to make the data stored in the first physical unit conforming to a second reliability level.

Claims

1. A memory management method for controlling a rewritable non-volatile memory module comprising a plurality of physical units, the memory management method comprising:

defining a first data management rule for a first type physical unit and a second data management rule for a second type physical unit, wherein a first data density of the first type physical unit is lower than a second data density of the second type physical unit;

determining whether a value of a valid count of a first physical unit of the physical units exceeds a threshold value, wherein the valid count relates to a number of logical unit to which the data stored in the first physical unit belongs and the value of the valid count is positively correlated with a data density of the first physical unit;

if the value of the valid count of the first physical unit exceeds the threshold value, managing the first physical unit based on the second data management rule, such that the data stored in the first physical unit conforms to a second reliability level and is protected based on a second protection level; and

if the value of the valid count of the first physical unit does not exceed the threshold value, managing the first physical unit based on the first data management rule, such that data stored in the first physical unit conforms to a first reliability level and is protected based on a first protection level,

wherein the second reliability level is higher than the first reliability level, and the second protection level is higher than the first protection level,

wherein a first number of logical units corresponding to the data stored in the first type physical unit is less than a second number of logical units corresponding to the data stored in the second type physical unit,

wherein the first physical unit which is managed based on any one of the first data management rule and the second data management rule is accessible.

2. The memory management method as claimed in claim 1, further comprising:

when performing a garbage collection process, determining whether the first physical unit of the physical units belongs to the first type physical unit or the second type physical unit, wherein the first physical unit is used for storing valid data collected in the garbage collection process.

3. The memory management method as claimed in claim 2, wherein the physical units comprise a non-spare physical unit, the non-spare physical unit comprises a first physical subunit storing valid data, and the memory management method further comprises:

when performing the garbage collection process, determining whether the first physical subunit belongs to a first type physical subunit or a second type physical subunit, or determining whether the non-spare physical unit belongs to the first type physical unit or the second type physical unit;

if the first physical subunit belongs to the first type physical subunit or the non-spare physical unit belongs to the first type physical unit, not copying the valid data stored in the first physical subunit to the first physical unit; and

if the first physical subunit belongs to the second type physical subunit or the non-spare physical unit belongs to the second type physical unit, copying the valid data stored in the first physical subunit to the first physical unit.

4. The memory management method as claimed in claim 1, further comprising:

when performing a data writing process requested by a host system, determining whether the first physical unit of the physical units belongs to the first type physical unit or the second type physical unit, wherein the first physical unit is used for storing write data corresponding to the data writing process.

5. The memory management method as claimed in claim 1, wherein the step of managing the first physical unit based on the first data management rule comprises:

not generating a lengthwise validation code corresponding to the first physical unit, wherein the lengthwise validation code is used for performing a lengthwise validation to data in the first physical unit;

wherein the step of managing the first physical unit based on the second data management rule comprises;

generating the lengthwise validation code corresponding to the first physical unit.

6. The memory management method as claimed in claim 1, wherein the step of managing the first physical unit based on the first data management rule comprises:

generating a first lengthwise validation code corresponding to the first physical unit,

wherein the step of managing the first physical unit based on the second data management rule comprises;

generating a second lengthwise validation code corresponding to the first physical unit, wherein the first lengthwise validation code is used for performing a first lengthwise validation to data in the first physical unit, and the second lengthwise validation code is used for performing a second lengthwise validation to the data in the first physical unit, and a length of the second lengthwise validation code is longer than a length of the first lengthwise validation code.

7. The memory management method as claimed in claim 1, wherein the step of managing the first physical unit based on the first data management rule comprises:

generating a first error correction code corresponding to data to be stored to the first physical unit,

wherein the step of managing the first physical unit based on the second data management rule comprises;

generating a second error correction code corresponding to the data to be stored to the first physical unit, wherein a length of the second error correction code is longer than a length of the first error correction code.

8. The memory management method as claimed in claim 1, wherein the step of managing the first physical unit based on the first data management rule comprises:

using the first physical unit in a predetermined programming mode,

wherein the step of managing the first physical unit based on the second data management rule comprises;

using the first physical unit in a fast page mode.

9. The memory management method as claimed in claim 1, wherein the step of managing the first physical unit based on the first data management rule comprises:

setting a writing voltage for the first physical unit as a predetermined writing voltage,

wherein the step of managing the first physical unit based on the second data management rule comprises;

dynamically adjusting the writing voltage of the first physical unit based on a using degree of at least one memory cell in the first physical unit.

10. A memory storage device, comprising:

a connecting interface unit, configured to be coupled to a host system;

a rewritable non-volatile memory module, comprising a plurality of physical units; and

a memory controlling circuit unit, coupled to the connecting interface unit and the rewritable non-volatile memory module,

wherein the memory controlling circuit unit is configured to define a first data management rule for a first type physical unit and a second data management rule for a second type physical unit, wherein a first data density of the first type physical unit is lower than a second data density of the second type physical unit,

wherein the memory controlling circuit unit is further configured to determine whether a value of a valid count of a first physical unit of the physical units is greater than a threshold value, wherein the valid count relates to a number of logical unit to which the data stored in the first physical unit belongs and the value of the valid count is positively correlated with a data density of the first physical unit,

wherein if the value of the valid count of the first physical unit exceeds the threshold value, the memory controlling circuit unit is further configured to manage the first physical unit based on the second data management rule, such that the data stored in the first physical unit conforms to a second reliability level and is protected based on a second protection level,

wherein if the value of the valid count of the first physical unit does not exceed the threshold value, the memory controlling circuit unit is further configured to manage the first physical unit based on the first data management rule, such that data stored in the first physical unit conforms to a first reliability level and is protected based on a first protection level,

wherein the second reliability level is higher than the first reliability level, and the second protection level is higher than the first protection level,

wherein a first number of logical units corresponding to the data stored in the first type physical unit is less than a second number of logical units corresponding to the data stored in the second type physical unit,

wherein the first physical unit which is managed based on any one of the first data management rule and the second data management rule is accessible.

11. The memory storage device as claimed in claim 10, wherein when a garbage collection process is performed, the memory controlling circuit unit is further configured to determine whether the first physical unit of the physical units belongs to the first type physical unit or the second type physical unit, wherein the first physical unit is used for storing valid data collected in the garbage collection process.

12. The memory storage device as claimed in claim 10, wherein when a data writing process requested by the host system is performed, the memory controlling circuit unit is further configured to determine whether the first physical unit of the physical units belong to the first type physical unit or the second type physical unit, wherein the first physical unit is used for storing write data corresponding to the data writing process.

13. The memory storage device as claimed in claim 10, wherein the operation that the memory controlling circuit unit manages the first physical unit based on the first data management rule comprises:

using the first physical unit in a predetermined programming mode,

wherein the operation that the memory controlling circuit unit manages the first physical unit based on the second data management rule comprises;

using the first physical unit in a fast page mode.

14. A memory controlling circuit unit for controlling a rewritable non-volatile memory module comprising a plurality of physical units, the memory controlling circuit unit comprises:

a host interface, configured to couple to a host system;

a memory interface, configured to couple to the rewritable non-volatile memory module; and

a memory management circuit, coupled to the host interface and the memory interface,

wherein the memory management circuit is configured to define a first data management rule for a first type physical unit and a second data management rule for a second type physical unit, wherein a first data density of the first type physical unit is lower than a second data density of the second type physical unit,

wherein the memory management circuit is further configured to determine whether a value of a valid count of a first physical unit of the physical units is greater than a threshold value, wherein the valid count relates to a number of logical unit to which the data stored in the first physical unit belongs and the value of the valid count is positively correlated with a data density of the first physical unit,

wherein if the value of the valid count of the first physical unit exceeds the threshold value, the memory management circuit is further configured to manage the first physical unit based on the second data management rule, such that the data stored in the first physical unit conforms to a second reliability level and is protected based on a second protection level,

wherein if the value of the valid count of the first physical unit does not exceed the threshold value, the memory management circuit is further configured to manage the first physical unit based on the first data management rule, such that data stored in the first physical unit conforms to a first reliability level and is protected based on a first protection level,

wherein the second reliability level is higher than the first reliability level, and the second protection level is higher than the first protection level,

wherein a first number of logical units corresponding to the data stored in the first type physical unit is less than a second number of logical units corresponding to the data stored in the second type physical unit,

wherein the first physical unit which is managed based on any one of the first data management rule and the second data management rule is accessible.