SEMICONDUCTOR MEMORY DEVICE AND DATA MANAGEMENT METHOD USING SEMICONDUCTOR MEMORY DEVICE

• US 20090089491A1
• Filed: 09/29/2008
• Published: 04/02/2009
• Est. Priority Date: 09/28/2007
• Status: Abandoned Application

• Current Assignee: Kabushiki Kaisha Toshiba (Toshiba Corporation)
• Original Assignee: Kabushiki Kaisha Toshiba (Toshiba Corporation)
• Inventors: HATANAKA, Koujiro, Kuriyama, Hikaru, Ohishi, Koji
• Application Number:
  US12/240,258
• Publication Number:
  US 20090089491A1
• Time in Patent Office: Days
• US Class Current: 711/103
• CPC Class Codes: G06F 12/0246 in block erasable memory, e.g. flash memory
• CPC Class Codes: G06F 2212/1036 Life time enhancement
• CPC Class Codes: G06F 2212/7202 Allocation control and policies
• CPC Class Codes: G11C 11/5621 using charge storage in a floating gate
• CPC Class Codes: G11C 16/0483 comprising cells having several storage transistors connected in series
• CPC Class Codes: G11C 2211/5641 Multilevel memory having cells with different number of storage levels

Abstract

A semiconductor memory device comprises: a memory part which has a plurality of memory blocks having a memory cell capable of storing a plurality of different kinds of data which require a memory area having different characteristics, and a memory controller which has a function of treating each of the memory blocks as a deletion unit in order to manage the memory part and converting a logic address of the memory part to a physical address identifying the memory block, and which replaces the memory block with a preregistered free block in rewriting the memory block. The memory controller manages the different kinds of data to be stored in the memory part so as to store the same kind of data as before, even after each of the memories and free blocks in the memory part are rewritten.

Claims

1. A semiconductor memory device, comprising:

a memory part which has a plurality of memory blocks having a memory cell capable of storing a plurality of different kinds of data which require a memory area having different characteristics; and

a memory controller which has a function of treating each of the memory blocks as a deletion unit in order to manage the memory part and converting a logic address of the memory part to a physical address identifying the memory block, and which replaces the memory block with a preregistered free block in rewriting the memory block,

wherein the memory controller manages the different kinds of data to be stored in the memory part so as to store the same kind of data as before, even after each of the memories and free blocks in the memory part are rewritten.

2. The semiconductor memory device according to claim 1,

wherein the memory controller builds a logic/physical address conversion table defining a corresponding relationship between a logic address of the memory part and a physical address of the memory block corresponding to the logic address, and refers to the logic/physical address conversion table in order to manage the different kinds of data to be stored in the memory part.

3. The semiconductor memory device according to claim 2,

wherein the memory controller configures a corresponding relationship between a memory area in the memory part and a memory block to be allocated to each memory area, and manages the different kinds of data to be stored in the memory part based on the corresponding relationship.

4. The semiconductor memory device according to claim 3,

wherein the memory controller registers to a free block table a memory block which is a part of the memory part as a free block, and when a written memory block in the memory part needs to be rewritten, the controller replaces the block to be rewritten with a free block included in the same memory area as the memory block to be rewritten, based on the corresponding relationship between the memory area and a memory block to be allocated to the memory area.

5. The semiconductor memory device according to claim 3,

wherein the memory controller registers a memory block which is a part of the memory part as a free block to a free block table which is arranged in each memory area, and when a written memory block in the memory part needs to be rewritten, the controller allocates a free block from a free block table which is the same kind as the data stored in a memory block which needs to be rewritten, and replaces it with the memory block which needs to be rewritten.

6. The semiconductor memory device according to claim 1, which includes binary data and multi-valued data in the different kinds of data.

7. The semiconductor memory device according to claim 1,

wherein the memory part includes a boot code block storing a boot code.

8. The semiconductor memory device according to claim 1,

wherein the memory part consists of a NAND type flash memory or a NOR type flash memory.

9. A semiconductor memory device comprising:

a memory part which has a plurality of memory blocks having a memory cell capable of storing data in a plurality of different kinds of writing/reading manners which require a memory area having different characteristics; and

a memory controller which has a function of treating each of the memory blocks as a deletion unit in order to manage the memory part and converting a logic address of the memory part to a physical address identifying the memory block, and which replaces the memory block with a preregistered free block in rewriting the memory block,

wherein the memory controller manages the different kinds of data to be stored in the memory part so as to store each of the memory blocks and free blocks in the memory part in the same writing and reading manner as before, even after rewriting.

10. The semiconductor memory device according to claim 9,

wherein the memory controller builds a logic/physical address conversion table defining a corresponding relationship between a logic address in the memory part and a physical address in the memory block corresponding to the logic address, and refers to the logic/physical address conversion table in order to store the different kinds of data to be stored in the memory part.

11. The semiconductor memory device according to claim 10,

wherein the memory controller configures a corresponding relationship between a memory area in the memory part and a memory block to be allocated to each memory block, and manages the different kinds of data to be stored in the memory part based on the corresponding relationship.

12. The semiconductor memory device according to claim 11,

wherein the memory controller registers to a free block table a memory block which is a part of the memory part as a free block, and when a written memory block in the memory part needs to be rewritten, the controller replaces the block to be rewritten with a free block included in the same memory area as the memory block to be rewritten based on the corresponding relationship between the memory area and a memory block to be allocated to the memory area.

13. The semiconductor memory device according to claim 11,

wherein the memory controller registers a memory block which is a part of the memory part as a free block to a free block table arranged in each memory area, and when a written memory block in the memory part needs to be rewritten, the controller allocates a free block from the same kind of free block table as the data stored in the memory block to be rewritten and replaces it with the memory block to be rewritten.

14. The semiconductor memory device according to claim 9, which includes binary data and multi-valued data in the different kinds of data.

15. A data management method using a semiconductor memory device, the device comprising:

a memory part which has a plurality of memory blocks having a memory cell capable of storing a plurality of different kinds of data which require a memory area having different characteristics; and

a memory controller which has a function of treating each of the memory blocks as a deletion unit in order to manage the memory part and converting a logic address of the memory part to a physical address identifying the memory block, and which replaces the memory block with a preregistered free block in rewriting the memory block,

wherein the different kinds of data to be stored in the memory part are managed by the memory controller so as to store the same kinds of data as before, even after each of the memory blocks and free blocks in the memory part are rewritten.

16. The data management method according to claim 15,

wherein a logic/physical address conversion table defining a corresponding relationship between a logic address of the memory part and a physical address of the memory block corresponding to the logic address is built, and the different kinds of data to be stored in the memory part are managed with reference to the logic/physical address conversion table by the memory controller.

17. The data management method according to claim 16,

wherein a corresponding relationship between a memory area in the memory part and a memory block allocated to each memory area are configured to manage the different kinds of data to be stored in the memory part based on the corresponding relationship by the memory controller.

18. The data management method according to claim 17,

wherein a memory block which is a part of the memory part is registered to a free block table as a free block and when a written memory block in the memory part needs to be rewritten, the block to be rewritten is replaced with the free block included in the same memory area as the memory block which needs to be rewritten based on the corresponding relationship between the memory area and a memory block to be allocated to a memory area by the memory controller.

19. The data management method according to claim 17,

wherein a memory block which is a part of the memory part is registered as a free block to a free block table arranged in each memory area, and when a written memory block in the memory part needs to be rewritten, a free block is allocated from the free block table which is the same kind as the data stored in the memory block to be rewritten, and replaced with the memory block to be rewritten by the memory controller.

20. The semiconductor memory device according to claim 15, which includes binary data and multi-valued data in the different kinds of data.