Nonvolatile memory unit with specific cache

• US 20050015557A1
• Filed: 12/27/2002
• Published: 01/20/2005
• Est. Priority Date: 12/27/2002
• Status: Abandoned Application

• Current Assignee: Solid State System Co., Ltd.
• Original Assignee: Solid State System Co., Ltd.
• Inventors: Kuo, Chun-Hao, Lin, Chun-Hung, Wang, Chih-Hung
• Application Number:
  US10/477,783
• Publication Number:
  US 20050015557A1
• Time in Patent Office: Days
• US Class Current: 711/154
• CPC Class Codes: G06F 12/0246 in block erasable memory, e.g. flash memory
• CPC Class Codes: G06F 12/0875 with dedicated cache, e.g. instruction or stack
• CPC Class Codes: G06F 2212/7203 Temporary buffering, e.g. using volatile buffer or dedicated buffer blocks
• CPC Class Codes: G06F 2212/7207 management of metadata or control data
• CPC Class Codes: G06F 3/0613 in relation to throughput
• CPC Class Codes: G06F 3/064 Management of blocks
• CPC Class Codes: G06F 3/0679 Non-volatile semiconductor memory device, e.g. flash memory, one time programmable memory [OTP]

Abstract

The invention provides a method for organizing a writing operation to a nonvolatile memory. The method comprises setting a specific cache area, into which a specific data belonging to a specific group of logical blocks is to be written. It is determined whether or not the writing operation is a random write. If the writing operation is the random write, then the following steps are performed: determining whether or not the writing operation is to write a data that is belonging to the specific group of logical blocks; and writing the data into the specific cache area if the data is belonging to the specific group of logical blocks. As a result, a swap action between a data block and a writing block can be avoided during a random write operation. A storage structure in a nonvolatile memory device are organized to perform the forgoing writing operation.

Claims

1. A method for organizing a writing operation to a nonvolatile memory, the method comprising:

setting a specific cache area, into which a specific data belonging to a specific group of logical blocks is to be written;

determining whether or not the writing operation is a random write, if the writing operation is the random write, then comprising the following steps;

determining whether or not the writing operation is to write a data that is belonging to the specific group of logical blocks; and

writing the data into the specific cache area if the data is belonging to the specific group of logical blocks;

wherein a swap action between a data block and a writing block can be avoided during a random write operation.

2. The method of claim 1, wherein in the step of setting the specific cache area, the specific cache area includes a FAT cache for storing a FAT-like data.

3. The method of claim 1, wherein in the step of setting the specific cache area, the specific cache area includes a corresponding cache for storing the data belonging to the specific group of logical blocks.

4. The method of claim 1, further comprising if the writing operation is not the random write, then directly writing the data into the writing block.

5. The method of claim 1, further comprising if the writing operation is to write the data that is not belonging to the specific group of logical blocks, then performing the swap action and writing the data into a new allocated writing block.

6. A method for organizing a writing operation to a nonvolatile memory, the method comprising:

setting a specific cache area;

determining whether or not the writing operation is a random write, if the writing operation is the random write, then comprising the following steps;

determining whether or not a sector count of a data to be written is less than a predetermined number; and

writing the data into the specific cache area if the sector count of the data is less than the predetermined number;

wherein a swap action between a data block and a writing block can be avoided during a random write operation.

7. The method of claim 6, wherein in the step of setting the specific cache area, the specific cache area includes a directory cache for storing a directory-like data.

8. The method of claim 6, further comprising if the writing operation is not the random write, then directly writing the data into the writing block.

9. The method of claim 6, further comprising if the sector count of the data is not less than the predetermined number, then performing the swap action and writing the data into a new allocated writing block.

10. A method for organizing a writing operation to a nonvolatile memory, the method comprising:

setting a specific cache area;

determining whether or not the writing operation is a random write, if the writing operation is the random write, then comprising the following steps;

determining whether or not the writing operation is to write a data that is belonging to the specific group of logical blocks;

writing the data into the specific cache area if the data is belonging to the specific group of logical blocks;

determining whether or not a sector count of the data to be written is less than a predetermined number; and

writing the data into the specific cache area if the sector count of the data is less than the predetermined number;

wherein a swap action between a data block and a writing block can be avoided during a random write operation.

11. The method of claim 10, wherein in the step of setting the specific cache area, the specific cache area includes a FAT cache for storing a directory-like data.

12. The method of claim 10, wherein in the step of setting the specific cache area, the specific cache area includes a directory cache for storing a directory-like data.

13. The method of claim 10, wherein in the step of setting the specific cache area, the specific cache area includes a corresponding cache for storing the data belonging to the specific group of logical blocks.

14. A nonvolatile memory unit, having a storage structure, within a memory storage device which can be accessed by a host, the nonvolatile memory unit including a plurality of physical blocks, used and managed by a control unit within the memory storage device, the control unit organizing the physical blocks into the storage structure, comprising:

a data block, composed of at least one physical block, and used to store a corresponding logical block information;

a writing block, serving as a temporary block for the data block;

optionally a spare block, which can be allocated to become the writing block; and

at least one specific cache area, which is used for writing-into a cached data, wherein the cached data includes a specific data belonging to a specific logical block, whereby a swap action for this time of writing the specific data is not always necessary even if a random write is desired.

15. The nonvolatile memory unit of claim 14, wherein the at least one specific cache area includes a FAT cache.

16. The nonvolatile memory unit of claim 14, wherein the at least one specific cache area includes a corresponding cache.

17. A nonvolatile memory unit, having a storage structure, within a memory storage device, which can be accessed by a host, the nonvolatile memory unit including a plurality of physical blocks, used and managed by a control unit within the memory storage device, the control unit organizing the physical blocks into a plurality of types of blocks, comprising:

a data block, composed of at least one physical block, and used to store a corresponding logical block information;

a writing block, serving as a temporary block for the data block;

optionally a spare block, which can be allocated to become the writing block; and

at least one specific cache area, which is used for writing-into a cached data, wherein a sector count of the cached data is less than a predetermined number, whereby a swap action for this time of writing the specific data is not always necessary even if a random write is desired.

18. The nonvolatile memory unit of claim 17, wherein the at least one specific cache area includes a directory cache.