Storage device employing a flash memory

• US 6,347,051 B2
• Filed: 05/30/2001
• Issued: 02/12/2002
• Est. Priority Date: 11/26/1991
• Status: Expired due to Term

• Current Assignee: Emergence Memory Solutions LLC
• Original Assignee: Hitachi, Ltd.
• Inventors: Hayashi, Yoshihiro, Katayama, Kunihiro, Yamagami, Hajime, Furuno, Takeshi, Terada, Kouichi, Kaki, Kenichi, Tsunehiro, Takashi
• Primary Examiner(s): Nguyen, Viet Q.
• Application Number:
  US09/866,622
• Publication Number:
  US 20010030890A1
• Time in Patent Office: 258 Days
• Field of Search: 365/189.01, 365/236.01, 365/185.29, 365/185.33, 365/230.03, 711/103, 711/203
• US Class Current: 365/185.09
• CPC Class Codes: G06F 12/0246 in block erasable memory, e.g. flash memory
• CPC Class Codes: G06F 2212/2022 Flash memory
• CPC Class Codes: G06F 3/0601 Interfaces specially adapted for storage systems
• CPC Class Codes: G06F 3/0616 in relation to life time, e.g. increasing Mean Time Between Failures [MTBF]
• CPC Class Codes: G06F 3/0619 in relation to data integrity, e.g. data losses, bit errors
• CPC Class Codes: G06F 3/064 Management of blocks
• CPC Class Codes: G06F 3/0659 Command handling arrangements, e.g. command buffers, queues, command scheduling
• CPC Class Codes: G06F 3/0664 at device level, e.g. emulation of a storage device or system
• CPC Class Codes: G06F 3/0679 Non-volatile semiconductor memory device, e.g. flash memory, one time programmable memory [OTP]
• CPC Class Codes: G11C 16/102 External programming circuits, e.g. EPROM programmers; In-circuit programming or reprogramming; EPROM emulators
• CPC Class Codes: G11C 16/349 Arrangements for evaluating degradation, retention or wearout, e.g. by counting erase cycles
• CPC Class Codes: G11C 29/765 in solid state disks

Abstract

A semiconductor disk wherein a flash memory into which data is rewritten in block unit is employed as a storage medium, the semiconductor disk including a data memory in which file data are stored, a substitutive memory which substitutes for blocks of errors in the data memory, an error memory in which error information of the data memory are stored, and a memory controller which reads data out of, writes data into and erases data from the data memory, the substitutive memory and the error memory. Since the write errors of the flash memory can be remedied, the service life of the semiconductor disk can be increased.

Claims

1. A storage device comprising:

a controller to carry out an interface with a host system, via a host bus, to receive instructions from said host system and to control operations to be performed within said storage device; and

a nonvolatile semiconductor flash memory coupled with said controller,

wherein said nonvolatile semiconductor flash memory is (i) electrically erasable and electrically programmable, (ii) includes a plurality of erase blocks in connection with an electrical erase operation, and (iii) is electrically programmable to store a sector data from said host system and to store address information,

wherein said controller includes an address table of a volatile memory, and is such as to allow a host logical address from said host system to be converted to a physical address of said nonvolatile semiconductor flash memory based on data stored in said address table of said volatile memory, and

wherein said data of said address table of said volatile memory is originated from said address information stored in said nonvolatile semiconductor flash memory by said controller at start of system operation, and then said controller accesses said nonvolatile semiconductor flash memory based upon said data of said address table of said volatile memory.

2. A storage device according to claim 1,

wherein application of a power supply is initiated at said start of system operation.

3. A storage device according to claim 2,

wherein each erase block of said plurality of erase blocks is electrically programmable to store a corresponding address information.

4. A storage device according to claim 3,

wherein said controller is a one-chip microcomputer including a random access memory (RAM) core as said volatile memory for storing said data of said address table.

5. A storage device according to claim 2,

wherein said controller is a one-chip microcomputer including a random access memory (RAM) core as said volatile memory for storing said data of said address table.

6. A storage device according to claim 1,

wherein said controller is a one-chip microcomputer including a random access memory (RAM) core as said volatile memory for storing said data of said address table.

7. A storage device according to claim 1,

wherein each erase block of said plurality of erase blocks is electrically programmable to store a corresponding address information.

8. A storage device according to claim 7,

wherein said controller is a one-chip microcomputer including a random access memory (RAM) core as said volatile memory for storing said data of said address table.

9. A storage device according to claim 1,

wherein said nonvolatile semiconductor flash memory is a flash memory chip.

10. A storage device according to claim 9,

wherein each erase block of said plurality of erase blocks is electrically programmable to store a corresponding address information.

11. A storage device according to claim 10,

wherein said controller is a one-chip microcomputer including a random access memory (RAM) core as said volatile memory for storing said data of said address table.

12. A storage device according to claim 9,

wherein said controller is a one-chip microcomputer including a random access memory (RAM) core as said volatile memory for storing said data of said address table.

13. A storage device according to claim 1,

wherein the flash memory includes a collective table area, which is provided from said plurality of erase blocks, for storing said address information.

14. A storage device according to claim 13,

wherein said nonvolatile semiconductor flash memory is a flash memory chip.

15. A storage device according to claim 14,

wherein said controller is a one-chip microcomputer including a random access memory (RAM) core as said volatile memory for storing said data of said address table.

16. A storage device according to claim 1,

wherein said controller is a one-chip microcomputer including a random access memory (RAM) core as said volatile memory for storing said data and a read-only memory (ROM)core for storing control programs for the microcomputer.

17. A storage device according to claim 16,

wherein each erase block of said plurality of erase blocks is electrically programmable to store a corresponding address information.

18. A storage device according to claim 17,

wherein the flash memory includes a collective table area, which is provided from said plurality of erase blocks, for storing said address information.

19. A storage device according to claim 18,

wherein said nonvolatile semiconductor flash memory is a flash memory chip.

20. A storage device according to claim 16,

wherein said nonvolatile semiconductor flash memory is a flash memory chip.

21. A storage device comprising:

a controller to control operations to be performed within said storage device,

wherein said controller includes a volatile memory to store data; and

a nonvolatile semiconductor flash memory coupled with said controller,

wherein said nonvolatile semiconductor flash memory is electrically erasable and electrically programmable, and includes a plurality of erase blocks in connection with an electrical erase operation, and

wherein said data of said volatile memory is originated from data stored in said nonvolatile semiconductor flash memory by said controller at start of system operation, and then said controller controls the operation of said nonvolatile semiconductor flash memory based upon said data stored by said volatile memory.

22. A storage device according to claim 21,

wherein application of a power supply is initiated at said start of system operation.

23. A storage device according to claim 22,

wherein said nonvolatile semiconductor flash memory is a flash memory chip.

24. A storage device according to claim 21,

wherein said nonvolatile semiconductor flash memory is a flash memory chip.