COOPERATIVE MEMORY MANAGEMENT

• US 20080189485A1
• Filed: 08/03/2007
• Published: 08/07/2008
• Est. Priority Date: 02/01/2007
• Status: Active Grant

• Current Assignee: Samsung Electronics Co. Ltd.
• Original Assignee: Samsung Electronics Co. Ltd.
• Inventors: Park, Chan-Ik, Oh, Sang-Jin, Jung, Myoung-Soo
• Granted Patent: US 8,745,309 B2
• Time in Patent Office: Days
• US Class Current: 711/115
• CPC Class Codes: G06F 12/0246 in block erasable memory, e.g. flash memory
• CPC Class Codes: G06F 2212/1041 Resource optimization
• CPC Class Codes: G06F 2212/7201 Logical to physical mapping or translation of blocks or pages
• CPC Class Codes: G06F 2212/7205 Cleaning, compaction, garbage collection, erase control
• CPC Class Codes: G06F 2212/7206 Reconfiguration of flash memory system
• CPC Class Codes: G11C 16/349 Arrangements for evaluating degradation, retention or wearout, e.g. by counting erase cycles

Abstract

A cooperative memory card system includes a memory card device, and a host in signal communication with the memory card device, where the host assumes at least one memory management function for the memory card device; and a corresponding method of cooperative memory management between a host and a memory card device includes selecting at least one of several memory management functions to be performed by the host for the device.

Claims

1. A cooperative memory card system comprising:

a memory card device; and

a host in signal communication with the memory card device,

wherein the host assumes at least one memory management function for the memory card device.

2. A system as defined in claim 1 wherein the host issues at least one command to the memory card device.

3. A system as defined in claim 2 wherein the at least one command comprises a command for at least one of a read, a write, a copy or an erase.

4. A system as defined in claim 2 wherein the at least one command comprises a command for at least one of a write to a single-level cell region or a write to a multi-level cell region.

5. A system as defined in claim 2 wherein the at least one command comprises a command for at least one of enabling or disabling at least one of encryption or decryption.

6. A system as defined in claim 1, the memory card device comprising at least one of flash memory, FRAM, PRAM, MRAM, DRAM or EEPROM.

7. A system as defined in claim 1 wherein the at least one memory management function is a flash translation layer task.

8. A system as defined in claim 1 wherein the at least one memory management function is an operating system task.

9. A system as defined in claim 1 wherein the at least one memory management function is a device driver task.

10. A system as defined in claim 1, the host comprising:

a host processor; and

a working memory in signal communication with the host processor.

11. A system as defined in claim 1 wherein the host performs resource checking of the memory card device and assumes the at least one task of the memory card device in response thereto.

12. A system as defined in claim 1 wherein the host checks its own available resources and assumes the at least one task of the memory card device in response thereto.

13. A system as defined in claim 1 wherein the host performs resource checking of the memory card device, compares the resources of the memory card device with available resources of the host, and assumes the at least one task of the memory card device in response to the comparison.

14. A system as defined in claim 1 wherein the at least one task of the memory card device assumed by the host is at least one of a function for address mapping, wear leveling, garbage collection, power-off recovery, bad block management, error correction coding, write buffering for real-time management, hot versus cold data management, encryption, decryption, compression or decompression.

15. A system as defined in claim 1 wherein vendor specific memory card device drivers include software modules for performing memory management functions.

16. A system as defined in claim 15 wherein the host determines which of the software modules for performing memory management functions will be loaded to the host.

17. A system as defined in claim 1 wherein the memory card device comprises at least one of a solid-state disk, USB card, SD card, MMC, Memory Stick or embedded device.

18. A system as defined in claim 17 wherein the embedded device comprises at least one of a moviNAND, GBNAND or iNAND.

19. A system as defined in claim 1, the memory card device comprising:

a controller; and

a memory in signal communication with the controller.

20. A system as defined in claim 19, the controller comprising:

a controller processor;

a read-only memory in signal communication with the controller processor; and

a buffer memory in signal communication with the controller processor.

21. A system as defined in claim 19, the memory comprising:

a region having memory management function code; and

a region having user data.

22. A system as defined in claim 21 wherein the region having memory management function code is a flash translation layer.

23. A system as defined in claim 21 wherein the at least one task of the memory card device assumed by the host is a function of the memory management function code.

24. A system as defined in claim 21 wherein the memory management function code comprises at least one of program instructions or data.

25. A system as defined in claim 19, the memory comprising:

a region having an operating system image; and

a region having user data.

26. A system as defined in claim 25 wherein memory management functions are embedded in a file system of the operating system image.

27. A system as defined in claim 25 wherein memory management functions are embedded in at least one device driver of the host.

28. A system as defined in claim 25 wherein memory management functions are embedded in a flash translation layer of the device.

29. A system as defined in claim 25 wherein the at least one task of the memory card device assumed by the host is a function of the operating system image.

30. A system as defined in claim 25 wherein the operating system image includes software modules for executing all memory management functions.

31. A system as defined in claim 25 wherein the operating system image does not include software modules for performing memory management functions.

32. A method of cooperative memory management between a host and a memory card device, the method comprising:

selecting at least one of a plurality of memory management functions to be performed by the host for the device.

33. A method as defined in claim 32, further comprising:

checking the available resources of at least one of the host or the device; and

selecting the at least one memory management function in response to the checked available resources.

34. A method as defined in claim 32 wherein the resources checked are those of the host.

35. A method as defined in claim 32 wherein the resources checked are those of the device.

36. A method as defined in claim 32 wherein the resources checked are those of the host and those of the device.

37. A method as defined in claim 32 wherein checking the available resources comprises the device issuing a request to the host for the host to perform the selected at least one memory management function.

38. A method as defined in claim 32 wherein the host issues at least one command to the memory card device.

39. A method as defined in claim 38 wherein the at least one command comprises a command for at least one of a read, a write, a copy or an erase.

40. A method as defined in claim 38 wherein the at least one command comprises a command for at least one of a write to a single-level cell region or a write to a multi-level cell region.

41. A method as defined in claim 38 wherein the at least one command comprises a command for at least one of enabling or disabling at least one of encryption or decryption.

42. A method as defined in claim 38 wherein the at least one command comprises a command for checking available resources of the device.

43. A method as defined in claim 38 wherein the at least one command is unconditional.

44. A method as defined in claim 32, further comprising loading the selected at least one memory management function from the memory card device to a random access memory of the host.

45. A method as defined in claim 32 wherein the at least one memory management function comprises a function of a flash translation layer.

46. A method as defined in claim 32, further comprising:

using the host to check the available resources of the memory card device;

comparing the available resources of the host with the available resources of the memory card device; and

determining which memory management functions will be performed in the host and which in the memory card device in response to the comparison.

47. A method as defined in claim 32 wherein the available resources of the host comprise at least one of processor type, processor speed, memory size, memory speed, bus type, bus speed, encryption type or encryption speed.

48. A method as defined in claim 32 wherein the memory management functions comprise at least one of address mapping, wear leveling, garbage collection or erase count accumulation.

49. A method as defined in claim 32 wherein the selected at least one memory management function for the host has a parameter set for the host but reset for the device.

50. A method as defined in claim 49 wherein the remainder of the memory management functions not selected for the host have parameters reset for the host but set for the device.

51. A method as defined in claim 32 wherein a communication protocol between the host and the device comprises at least one of a universal serial bus protocol or an advanced technology attachment protocol.

52. A method as defined in claim 32 wherein the selected at least one memory management function is comprised by flash translation layer code from the memory card device.

53. A method as defined in claim 32 wherein the selected at least one memory management function is comprised by a device driver.

54. A method as defined in claim 32 wherein the selected at least one memory management function is comprised by an operating system from the memory card device.

55. A method as defined in claim 32, further comprising:

loading memory management function code from a memory of the memory card device into a controller random access memory of the memory card device; and

loading an operating system from the memory of the memory card device into the random access memory of the host.

56. A method as defined in claim 55, further comprising initializing the operating system in the host.

57. A method as defined in claim 32, further comprising loading at least one vendor specific memory card device driver into a random access memory of the host.

58. A method as defined in claim 32, further comprising loading meta data from the memory card device to the host.

59. A method as defined in claim 58 wherein the meta data comprises at least one of erase count data, garbage collection data or mapping table data loaded to the host random access memory from the memory card device.

60. A method as defined in claim 32, further comprising initializing the selected memory management functions in the host.

61. A method as defined in claim 32, further comprising activating the selected memory management functions in the host.

62. A method as defined in claim 32, further comprising:

producing a write request from the host;

reading mapping information using host memory management functions;

checking for write space available on the memory card device; and

sending the write request to the device if there is write space available on the device.

63. A method as defined in claim 32, further comprising:

checking for garbage blocks on the memory card device;

if there are no garbage blocks on the device, performing garbage collection, designating garbage blocks and updating garbage collection data; and

erasing the garbage blocks.

64. A method as defined in claim 32, further comprising:

checking the need for wear leveling on the memory card device; and

if wear leveling is needed, performing wear leveling and updating meta data for wear leveling.