Non-volatile memory cache performance improvement

• US 20050246487A1
• Filed: 05/03/2004
• Published: 11/03/2005
• Est. Priority Date: 05/03/2004
• Status: Active Grant

• Current Assignee: Microsoft Technology Licensing LLC (Microsoft Corporation)
• Original Assignee: Microsoft Corporation
• Inventors: Fortin, Michael R., Obr, Nathan Steven, Ergan, Cenk, Kodavalla, Hanumantha R., Parchem, John M., Zwilling, Michael J., Westerinen, William J., Nicholson, Clark D., Teodosiu, Dan, Powell, Therron, Nagar, Rajeev Y., Stemen, Patrick L., DeWhitt, Dean L., Verma, Surenda, Hill, Emily Nicole, Zbikowski, Mark Joseph
• Granted Patent: US 7,644,239 B2
• Time in Patent Office: Days
• US Class Current: 711/113
• CPC Class Codes: G06F 12/08 in hierarchically structured memory systems, e.g. virtual memory systems
• CPC Class Codes: G06F 12/0866 for peripheral storage systems, e.g. disk cache
• CPC Class Codes: G06F 2212/1016 Performance improvement
• CPC Class Codes: G06F 2212/222 Non-volatile memory
• CPC Class Codes: G06F 2212/281 Single cache
• CPC Class Codes: G06F 2212/305 being part of a memory device, e.g. cache DRAM
• CPC Class Codes: G06F 2212/312 In storage controller
• CPC Class Codes: G06F 2212/313 In storage device
• CPC Class Codes: G06F 3/061 Improving I/O performance
• CPC Class Codes: G06F 3/0656 Data buffering arrangements
• CPC Class Codes: G06F 3/0679 Non-volatile semiconductor memory device, e.g. flash memory, one time programmable memory [OTP]
• CPC Class Codes: Y02D 10/00 Energy efficient computing, e.g. low power processors, power management or thermal management

Abstract

In order to provide a more efficient persistent storage device, one or more long-term storage media are included along with a non-volatile memory. In one embodiment, one portion of the non-volatile memory is used as a write buffer and a read cache for writes and reads to the long-term storage media. Interfaces are provided for controlling the use of the non-volatile memory as a write buffer and a read cache. Additionally, a portion of the non-volatile memory is used to provide a direct mapping for specified sectors of the long-term storage media. Descriptive data regarding the persistent storage device is stored in another portion of the non-volatile memory.

Claims

1. A method of operating a computer system having a non-volatile memory and a long-term storage medium, comprising:

utilizing at least a portion of said non-volatile memory as a write buffer for intermediate storage of data from write operations to said long-term storage medium; and

providing an interface for requesting that data written to said write buffer be transferred to said long-term storage medium.

2. The method of claim 1, further comprising:

providing an interface for requesting that a preparatory action be performed on said long-term storage medium to prepare said long-term storage medium for writing.

3. The method of claim 2, where said long-term storage medium comprises a rotating storage medium, and said preparatory action comprises spinning up said rotating storage medium.

4. The method of claim 3, where said preparatory action occurs more slowly than the fastest possible speed for said preparatory action.

5. The method of claim 2, further comprising:

detecting that said preparatory action has been performed;

transferring first data written to said write buffer to said long-term storage medium.

6. The method of claim 5, further comprising:

determining that a set of second data is available for transfer to said long-term storage;

upon detection that said preparatory action has been performed, transferring said second data to said long-term storage.

7. The method of claim 1, further comprising:

providing an interface for requesting that an action be performed on said long-term storage medium to deactivate it temporarily for writing.

8. The method of claim 7, where said long-term storage medium comprises a rotating storage medium, and said action comprises spinning down said rotating storage medium.

9. The method of claim 8, where said deactivation action occurs more slowly than the fastest possible speed for said preparatory action.

10. The method of claim 1, further comprising:

providing an interface for requesting that certain specified data in one or more write operations be written directly to said long-term storage medium rather than to said write buffer.

11. The method of claim 1, where, for each element of data stored in said write buffer, a priority indication is assigned to said element, where said interface for requesting that data be transferred to said long-term storage medium comprises an indication of a level of priority, and where, for each element of data stored in said write buffer, whether said element is transferred to said long-term storage medium is based on said indication and said assigned level of priority for said element.

12. The method of claim 1, further comprising:

providing an interface for indicating that certain specified data stored in said non-volatile memory is invalid.

13. The method of claim 12, where said invalid data is not transferred to said long-term storage medium.

14. The method of claim 13, where a location in said non-volatile memory used for said invalid data is made available for use to store other data.

15. The method of claim 1, further comprising:

providing an interface for receiving information regarding said non-volatile memory.

16. The method of claim 15, where said information comprises whether said non-volatile memory is present.

17. The method of claim 15, where said information comprises the size of said non-volatile memory.

18. The method of claim 1, where said information comprises at least one selected from among the following:

usage information regarding said non-volatile memory; and

type of said non-volatile memory.

19. The method of claim 1, further comprising:

providing a control ensuring that different physical locations within said non-volatile memory are erased with approximately equal frequency.

20. A computer-readable medium having computer-executable instructions to perform the method of claim 1.

21. A method of performing an atomic write operation of certain data to a long-term storage medium in a computer system having a non-volatile memory and said long-term storage medium, comprising:

attempting to write said certain data to said non-volatile memory;

if said attempt is successful, transferring said certain data to said long-term storage medium.

22. The method of claim 21, where if said attempt is unsuccessful, failure data comprising an indication of failure is returned.

23. A database application where atomic write operations are performed according to the method of claim 21.

24. A computer-readable medium having computer-executable instructions to perform the method of claim 21.

25. A method of operating a computer system having a non-volatile memory and a long-term storage medium, comprising:

utilizing at least a portion of said non-volatile memory as a read buffer for storage of data from said long-term storage medium; and

providing an interface for requesting that certain data be read from said long-term storage media into said portion of non-volatile memory.

26. The method of claim 25, further comprising:

providing an interface for requesting that a preparatory action be performed on said long-term storage medium to prepare said long-term storage medium for reading.

27. The method of claim 26, where said long-term storage medium comprises a rotating storage medium, and said preparatory action comprises spinning up said rotating storage medium.

28. The method of claim 25, further comprising:

providing an interface for requesting that an action be performed on said long-term storage medium to deactivate it temporarily for reading.

29. The method of claim 28, where said long-term storage medium comprises a rotating storage medium, and said action comprises spinning down said rotating storage medium.

30. The method of claim 25, where, for each element of data stored in said read buffer, a priority indication is assigned to said element, where portions of said read buffer are periodically reassigned for other purposes, and where whether a first portion of said read buffer is reassigned before a second portion of said read buffer is based on the relative values of a first priority indication assigned to elements of data in said first portion and a second priority indication assigned to elements of data stored in said second portion.

31. The method of claim 30, where at least one of said other uses comprise use as a write buffer for intermediate storage of data from write operations to said long-term storage medium;

and where said method further comprises;

providing an interface for requesting that data written to said write buffer be transferred to said long-term storage medium.

32. A computer-readable medium having computer-executable instructions to perform the method of claim 25.

33. A method of operating a computer system having a non-volatile memory and a long-term storage medium, comprising:

setting up a direct correspondence of at least one non-volatile memory storage element of said non-volatile memory with at least one long-term storage element of said long-term storage medium;

reading data from said long-term storage element to said non-volatile storage element;

performing any write operations directed at said long-term storage element in said non-volatile storage element; and

responding to any read operations directed at said long-term storage element by reading data from said non-volatile storage element.

34. The method of claim 33, where said method further comprises providing an interface for requesting that said direct correspondence be altered.

35. The method of claim 33, further comprising, in response to said request that said direct correspondence be altered:

reading second data from each non-volatile memory storage element to said corresponding long-term storage element of said long-term storage medium;

reading third data from at least one long-term storage element to non-volatile memory according to a second direct correspondence of at least one non-volatile memory storage element of said non-volatile memory with at least one long-term storage element of said long-term storage medium;

writing fourth data from write operations directed at said long-term storage elements to said non-volatile storage element in accordance with said second direct correspondence; and

reading fifth data in response to read operations directed at said long-term storage element from said non-volatile storage element in accordance with said second direct correspondence.

36. A computer-readable medium having computer-executable instructions to perform the method of claim 33.

37. A method of operating a computer system having persistent storage device comprising a non-volatile memory and a long-term storage medium, comprising:

utilizing at least a portion of said non-volatile memory as storage for descriptive information concerning said persistent storage device; and

providing a method for reading data from said portion.

38. The method of claim 37, where said descriptive information comprises a label for said persistent storage device.

39. The method of claim 37, where said descriptive information comprises usage statistics information about said long term storage medium.

40. The method of claim 39, where said usage statistics information comprises one or more of the following:

number of sectors written on said long-term storage medium;

number of times a specific action has been performed on said long-term storage medium;

number of bad sectors on said long-term storage medium;

type of said non-volatile memory; and

expected lifetime information for said non-volatile memory.

41. The method of claim 37, where said method comprises an interface for requesting that data from said portion be returned.

42. The method of claim 37, where said persistent storage device further comprises a display, and where said method comprises displaying data from said portion.

43. A computer-readable medium having computer-executable instructions to perform the method of claim 37.

44. A method of defragmenting memory in a computer system having a non-volatile memory and a long-term storage medium, comprising:

storing a first portion of data previously stored in said long-term memory in said non-volatile memory;

changing memory locations of a second portion of data stored in a first set of memory locations in said long-term storage medium such that said second portion of data is stored in a second set of memory locations, wherein said second set of memory locations is more contiguous than said first set of memory locations; and

writing said first portion of data to said long-term memory.

45. A computer-readable medium having computer-executable instructions to perform the method of claim 44.

46. A method of operating a computer system having a non-volatile memory and a long-term storage medium, comprising:

storing boot data required for initializing said computer system in said non-volatile memory;

utilizing said boot data in order to initialize said computer system; and

performing a preparatory action on said long-term storage medium to prepare said long-term storage medium for activity.

47. The method of claim 46, further comprising:

receiving a request to transition said computer to a shut-down state; and

storing second boot data required for a subsequent initialization of said computer system in said non-volatile memory.

48. The method of claim 47, where said storing second boot data comprises:

performing a preparatory action on said long-term storage medium to prepare said long-term storage medium for activity;

writing other data from said non-volatile memory to said long-term storage medium; and

storing said second boot data in said non-volatile memory.

49. A computer-readable medium having computer-executable instructions to perform the method of claim 46.

50. A method of operating a computer system having a non-volatile memory and a long-term storage medium, comprising:

storing operational data regarding the operations of said computer system in said non-volatile memory; and

using said operational data to analyze said operations of said computer system after a failure of said computer system.

51. The method of claim 50, where said operational data comprises one selected from among the following:

process information regarding processes running in said computer system;

thread information regarding threads running in said computer system;

data accesses; and

device accesses.

52. A computer-readable medium having computer-executable instructions to perform the method of claim 50.

53. A method of storing data in a computer system having a non-volatile memory and a long-term storage medium, comprising:

storing a first version of data;

creating a second version of said data in said non-volatile memory; and

updating said second version of said data with at least one data change.

54. The method of claim 53, where said first version is stored in non-volatile memory.

55. The method of claim 53, where said first version of data is stored in said long-term storage medium, and where said first version of data is indicated as the current version of said data, further comprising:

changing said indication to indicate that said first version is indicated as an archived version.

56. A computer-readable medium having computer-executable instructions to perform the method of claim 53.

57. A computer system utilizing a non-volatile memory and a long-term storage medium, comprising:

logic for utilizing at least a portion of said non-volatile memory as a write buffer for intermediate storage of data from write operations to said long-term storage medium; and

logic for providing an interface for requesting that data written to said write buffer be transferred to said long-term storage medium.

58. The computer system of claim 57, further comprising:

logic for providing an interface for requesting that a preparatory action be performed on said long-term storage medium to prepare said long-term storage medium for writing.

59. The computer system of claim 58, where said long-term storage medium comprises a rotating storage medium, and said preparatory action comprises spinning up said rotating storage medium.

60. The computer system of claim 59, where said preparatory action occurs more slowly than the fastest possible speed for said preparatory action.

61. The computer system of claim 58, further comprising:

logic for detecting that said preparatory action has been performed; and

logic for transferring first data written to said write buffer to said long-term storage medium.

62. The computer system of claim 61, further comprising:

logic for determining that a set of second data is available for transfer to said long-term storage;

logic for, upon detection that said preparatory action has been performed, transferring said second data to said long-term storage.

63. The computer system of claim 57, further comprising:

logic for providing an interface for requesting that an action be performed on said long-term storage medium to deactivate it temporarily for writing.

64. The computer system of claim 63, where said long-term storage medium comprises a rotating storage medium, and said action comprises spinning down said rotating storage medium.

65. The computer system of claim 64, where said deactivation action occurs more slowly than the fastest possible speed for said preparatory action.

66. The computer system of claim 57, further comprising:

logic for providing an interface for requesting that certain specified data in one or more write operations be written directly to said long-term storage medium rather than to said write buffer.

67. The computer system of claim 57, where, for each element of data stored in said write buffer, a priority indication is assigned to said element, where said interface for requesting that data be transferred to said long-term storage medium comprises an indication of a level of priority, and where, for each element of data stored in said write buffer, whether said element is transferred to said long-term storage medium is based on said indication and said assigned level of priority for said element.

68. The computer system of claim 57, further comprising:

logic for providing an interface for indicating that certain specified data stored in said non-volatile memory is invalid.

69. The computer system of claim 68, where said invalid data is not transferred to said long-term storage medium.

70. The computer system of claim 69, where a location in said non-volatile memory used for said invalid data is made available for use to store other data.

71. The computer system of claim 57, further comprising:

logic for providing an interface for receiving information regarding said non-volatile memory.

72. The computer system of claim 71, where said information comprises whether said non-volatile memory is present.

73. The computer system of claim 71, where said information comprises the size of said non-volatile memory.

74. The computer system of claim 57, where said information comprises at least one selected from among the following:

usage information regarding said non-volatile memory; and

type of said non-volatile memory.

75. The computer system of claim 57, further comprising:

logic for providing a control ensuring that different physical locations within said non-volatile memory are erased with approximately equal frequency.

76. A computer system allowing an atomic write operation of certain data to a long-term storage medium, said computer system utilizing a non-volatile memory and a long-term storage medium, said computer system comprising:

having a non-volatile memory and said long-term storage medium, comprising;

logic for attempting to write said certain data to said non-volatile memory;

logic for, if said attempt is successful, transferring said certain data to said long-term storage medium.

77. The computer system of claim 76, where if said attempt is unsuccessful, failure data comprising an indication of failure is returned.

78. A computer system utilizing a non-volatile memory and a long-term storage medium, comprising:

logic for utilizing at least a portion of said non-volatile memory as a read buffer for storage of data from said long-term storage medium; and

logic for providing an interface for requesting that certain data be read from said long-term storage media into said portion of non-volatile memory.

79. The computer system of claim 78, further comprising:

logic for providing an interface for requesting that a preparatory action be performed on said long-term storage medium to prepare said long-term storage medium for reading.

80. The computer system of claim 79, where said long-term storage medium comprises a rotating storage medium, and said preparatory action comprises spinning up said rotating storage medium.

81. The computer system of claim 78, further comprising:

logic for providing an interface for requesting that an action be performed on said long-term storage medium to deactivate it temporarily for reading.

82. The computer system of claim 81, where said long-term storage medium comprises a rotating storage medium, and said action comprises spinning down said rotating storage medium.

83. The computer system of claim 78, where, for each element of data stored in said read buffer, a priority indication is assigned to said element, where portions of said read buffer are periodically reassigned for other purposes, and where whether a first portion of said read buffer is reassigned before a second portion of said read buffer is based on the relative values of a first priority indication assigned to elements of data in said first portion and a second priority indication assigned to elements of data stored in said second portion.

84. The computer system of claim 83, where at least one of said other uses comprise use as a write buffer for intermediate storage of data from write operations to said long-term storage medium;

and where said computer system further comprises;

logic for providing an interface for requesting that data written to said write buffer be transferred to said long-term storage medium.

85. A computer system utilizing a non-volatile memory and a long-term storage medium, comprising:

logic for setting up a direct correspondence of at least one non-volatile memory storage element of said non-volatile memory with at least one long-term storage element of said long-term storage medium;

logic for reading data from said long-term storage element to said non-volatile storage element;

logic for performing any write operations directed at said long-term storage element in said non-volatile storage element; and

logic for responding to any read operations directed at said long-term storage element by reading data from said non-volatile storage element.

86. The computer system of claim 85, where said computer system further comprises providing an interface for requesting that said direct correspondence be altered.

87. The computer system of claim 85, further comprising, in response to said request that said direct correspondence be altered:

logic for writing second data from each non-volatile memory storage element to said corresponding long-term storage element of said long-term storage medium;

logic for reading third data from at least one long-term storage element to non-volatile memory according to a second direct correspondence of at least one non-volatile memory storage element of said non-volatile memory with at least one long-term storage element of said long-term storage medium;

logic for performing write operations directed at said long-term storage elements on said non-volatile storage element in accordance with said second direct correspondence; and

logic for performing read operations directed at said long-term storage element by reading data from said non-volatile storage element in accordance with said second direct correspondence.

88. A computer system utilizing a non-volatile memory and a long-term storage medium, comprising:

utilizing at least a portion of said non-volatile memory as storage for descriptive information concerning said persistent storage device; and

providing a computer system for reading data from said portion.

89. The computer system of claim 88, where said descriptive information comprises a label for said persistent storage device.

90. The computer system of claim 88, where said descriptive information comprises usage statistics information about said long term storage medium.

91. The computer system of claim 90, where said usage statistics information comprises one or more of the following:

number of sectors written on said long-term storage medium;

number of times a specific action has been performed on said long-term storage medium;

number of bad sectors on said long-term storage medium;

type of said non-volatile memory; and

expected lifetime information for said non-volatile memory.

92. The computer system of claim 88, where said computer system comprises an interface for requesting that data from said portion be returned.

93. The computer system of claim 88, where said persistent storage device further comprises a display, and where said computer system comprises displaying data from said portion.

94. A computer system with defragmenting capability, said computer system utilizing a non-volatile memory and a long-term storage medium, comprising:

logic for storing a first portion of data previously stored in said long-term memory in said non-volatile memory;

logic for changing memory locations of a second portion of data stored in a first set of memory locations in said long-term storage medium such that said second portion of data is stored in a second set of memory locations, wherein said second set of memory locations is more contiguous than said first set of memory locations; and

logic for writing said first portion of data to said long-term memory.

95. A computer system utilizing a non-volatile memory and a long-term storage medium, comprising:

logic for storing boot data required for initializing said computer system in said non-volatile memory;

logic for utilizing said boot data in order to initialize said computer system; and

logic for;

performing a preparatory action on said long-term storage medium to prepare said long-term storage medium for activity.

96. The computer system of claim 95, further comprising:

logic for receiving a request to transition said computer to a shut-down state; and

logic for storing second boot data required for a subsequent initialization of said computer system in said non-volatile memory.

97. The computer system of claim 96, where said storing second boot data comprises:

logic for performing a preparatory action on said long-term storage medium to prepare said long-term storage medium for activity;

logic for writing other data from said non-volatile memory to said long-term storage medium; and

logic for storing said second boot data in said non-volatile memory.

98. A computer system utilizing a non-volatile memory and a long-term storage medium, comprising:

logic for storing operational data regarding the operations of said computer system in said non-volatile memory; and

logic for using said operational data to analyze said operations of said computer system after a failure of said computer system.

99. The computer system of claim 98, where said operational data comprises one selected from among the following:

process information regarding processes running in said computer system;

thread information regarding threads running in said computer system;

data accesses; and

device accesses.

100. A computer system utilizing a non-volatile memory and a long-term storage medium, comprising:

logic for storing a first version of data;

logic for creating a second version of said data in said non-volatile memory; and

logic for updating said second version of said data with at least one data change.

101. The computer system of claim 100, where said first version is stored in non-volatile memory.

102. The computer system of claim 100, where said first version of data is stored in said long-term storage medium, and where said first version of data is indicated as the current version of said data, further comprising:

logic for changing said indication to indicate that said first version is indicated as an archived version.