Configuring file structures and file system structures in a memory device

• US 6,925,545 B2
• Filed: 03/22/2004
• Issued: 08/02/2005
• Est. Priority Date: 09/15/2000
• Status: Expired due to Term

• Current Assignee: SanDisk Technologies LLC (Western Digital Corporation)
• Original Assignee: Matrix Semiconductor, Inc. (Western Digital Corporation)
• Inventors: Brown, Daniel T., Moore, Christopher S., March, Roger W.
• Primary Examiner(s): PORTKA, GARY J
• Application Number:
  US10/806,826
• Publication Number:
  US 20040177229A1
• Time in Patent Office: 498 Days
• Field of Search: 711/101, 711/102, 711/103, 711/170, 711/171, 711/172, 711/173, 707/100, 707/101, 707/102, 707/205
• US Class Current: 711/170
• CPC Class Codes: G06F 11/1008 in individual solid state devices G06F11/1004 takes precedence
• CPC Class Codes: G06F 2003/0697 device management, e.g. handlers, drivers, I/O schedulers
• CPC Class Codes: G06F 3/0601 Interfaces specially adapted for storage systems
• CPC Class Codes: G06F 3/0619 in relation to data integrity, e.g. data losses, bit errors
• CPC Class Codes: G06F 3/0631 by allocating resources to storage systems
• CPC Class Codes: G06F 3/0643 Management of files
• CPC Class Codes: G06F 3/0679 Non-volatile semiconductor memory device, e.g. flash memory, one time programmable memory [OTP]
• CPC Class Codes: G06F 3/08 from or to individual record carriers, e.g. punched card , memory card, integrated circuit [IC] card or smart card
• CPC Class Codes: G11C 17/00 Read-only memories programmable only once; Semi-permanent stores, e.g. manually-replaceable information cards
• CPC Class Codes: Y10S 707/99934 Query formulation, input preparation, or translation
• CPC Class Codes: Y10S 707/99943 Generating database or data structure, e.g. via user interface
• CPC Class Codes: Y10S 707/99953 Recoverability
• CPC Class Codes: Y10S 707/99956 File allocation

Abstract

The preferred embodiments described herein provide a memory device and methods for use therewith. In one preferred embodiment, a method is presented for using a file system to dynamically respond to variability in an indicated minimum number of memory cells of first and second write-once memory devices. In another preferred embodiment, a method for overwriting data in a memory device is described in which an error code is disregarded after a destructive pattern is written. In yet another preferred embodiment, a method is presented in which, after a block of memory has been allocated for a file to be stored in a memory device, available lines in that block are determined. Another preferred embodiment relates to reserving at least one memory cell in a memory device for file structures or file system structures. A memory device is also provided in which file system structures of at least two file systems are stored in the same memory partition. Additionally, methods for permanently preventing modification of data stored in a memory device and for identifying memory cells storing data are disclosed.

Claims

1. A method for writing file system structures of two different file systems into a partition of memory cells of a memory device, the method comprising:

(a) creating a partition of memory cells in a memory device;

(b) reserving a first set of memory cells in the partition for a file system structure of a first file system;

(c) reserving a second set of memory cells in the partition for a file system structure of a second file system different from the first file system;

(d) storing the file system structure of the first file system in the reserved first set of memory cells; and

(e) storing the file system structure of the second file system in the reserved second set of memory cells;

wherein the first file system comprises a FAT file system, wherein the second file system comprises a file system other than a FAT file system, wherein file system structures of the FAT file system are stored in the reserved first set of memory cells but not in the reserved second set of memory cells, and wherein file system structures of the file system other than a FAT file system are stored in the reserved second set of memory cells but not in the reserved first set of memory cells.

2. The method of claim 1, wherein (e) is performed in response to a request from a user of the memory device.

3. The method of claim 1, wherein (e) is performed automatically by a file system in communication with the memory device.

4. The method of claim 1, wherein the memory device is logically organized into a plurality of blocks, each block comprising a plurality of lines;

and wherein at least one of the reserved first and second sets of memory cells comprises a line.

5. The method of claim 4, wherein a line comprises a minimum number of memory cells that can be written into during a write operation.

6. The method of claim 1, wherein the memory device is logically organized into a plurality of blocks, each block comprising at least one line;

and wherein at least one of the reserved first and second sets of memory cells comprises a block.

7. The method of claim 6, wherein a line comprises a minimum number of memory cells that can be written into during a write operation.

8. The method of claim 1, wherein the memory device comprises a write-once memory device.

9. The method of claim 1, wherein the memory device comprises a three-dimensional write-once memory device.

10. A memory device comprising a partition of memory cells, the memory device comprising:

a first set of memory cells reserved in a partition for a file system structure of a first file system; and

a second set of memory cells reserved in the partition for a file system structure of a second file system different from the first file system;

wherein the first file system comprises a FAT file system, wherein the second file system comprises a file system other than a FAT file system, wherein file system structures of the FAT file system are stored in the first set of memory cells but not in the second set of memory cells, and wherein file system structures of the file system other than a FAT file system are stored in the second set of memory cells but not in the first set of memory cells.

11. The memory device of claim 10, wherein the memory device comprises a write-once memory device.

12. The invention of claim 10, wherein the memory device comprises a three-dimensional write-once memory device.