NON-VOLATILE TEMPORARY DATA HANDLING

• US 20130024600A1
• Filed: 07/18/2011
• Published: 01/24/2013
• Est. Priority Date: 07/18/2011
• Status: Active Grant

• Current Assignee: Apple Inc.
• Original Assignee: Apple Inc.
• Inventors: Wakrat, Nir J., Post, Daniel J.
• Granted Patent: US 8,949,508 B2
• 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 12/08 in hierarchically structured memory systems, e.g. virtual memory systems
• 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 2212/7209 Validity control, e.g. using flags, time stamps or sequence numbers
• CPC Class Codes: G06F 9/4418 Suspend and resume; Hibernate and awake

Abstract

Systems and methods are provided for handling temporary data that is stored in a non-volatile memory, such as NAND flash memory. The temporary data may include hibernation data or any other data needed for only one boot cycle of an electronic device. When storing the temporary data in one or more pages of the non-volatile memory, the electronic device can store a temporary marker as part of the metadata in at least one of the pages. This way, on the next bootup of the electronic device, the electronic device can use the temporary marker to determine that the associated page contains unneeded data. The electronic device can therefore invalidate the page and omit the page from its metadata tables.

Claims

1. An electronic device comprising:

a volatile memory for storing temporary data;

a non-volatile (“

NV”

) memory comprising a plurality of pages;

control circuitry operative to store the temporary data in the non-volatile memory as NV temporary data, wherein the control circuitry stores a temporary marker in at least one of the pages in which the NV temporary data is stored.

2. The electronic device of claim 1, wherein the electronic device is further operative to:

prepare metadata for the NV temporary data; and

store the metadata and the temporary marker in a metadata field of the at least one of the pages in which the NV temporary data is stored.

3. The electronic device of claim 1, wherein the temporary marker comprises a predetermined bit pattern.

4. The electronic device of claim 1, wherein the plurality of pages are organized into blocks, and wherein the control circuitry is further operative to:

select one of the blocks for storing the NV temporary data; and

store a temporary marker in at least one page of the selected block.

5. The electronic device of claim 4, wherein the control circuitry is further operative to store a temporary marker in all of the pages of the selected block.

6. The electronic device of claim 1, and wherein the control circuitry is further operative to:

identify that the volatile memory is in a low memory state; and

store the temporary data in the non-volatile memory responsive to identifying the low memory state.

7. The electronic device of claim 1, wherein the control circuitry is further operative to select lower-performance pages for storing the temporary data.

8. The electronic device of claim 1, wherein the control circuitry is further operative to select a higher-speed programming technique for storing the temporary data.

9. A method of storing data in a non-volatile memory, wherein the non-volatile memory comprises a plurality of pages, the method comprising:

identifying the data as temporary data;

preparing metadata for the data, wherein the metadata comprises a temporary marker; and

storing the data and the metadata in at least one page of the non-volatile memory.

10. The method of claim 9, further comprising:

providing the data from a file system to a non-volatile memory interface with a write request,

wherein the identifying is performed by the non-volatile memory interface in response to the write request.

11. The method of claim 9, wherein the temporary marker comprises at least one bit of a predetermined value.

12. The method of claim 9, wherein the preparing further comprises determining a logical-to-physical address mapping for the data.

13. The method of claim 9, further comprising selecting the at least one page of the non-volatile memory based on the identifying.

14. The method of claim 9, further comprising:

identifying additional data for storage in the non-volatile memory, wherein the additional data is identified as not being temporary data;

preparing additional metadata for the additional data, wherein the additional metadata does not include a temporary marker; and

storing the additional data and the additional metadata in at least one other page of the non-volatile memory.

15. The method of claim 9, wherein the identifying comprises identifying that the data comprises at least one of hardware-based hibernation data, application-generated data, application-based hibernation data, and data for a virtual memory scheme.

16. An electronic device comprising:

a non-volatile memory;

control circuitry operative to create a metadata table for the non-volatile memory at bootup of the electronic device, wherein creating the metadata table comprises;

reading a plurality of pages of the non-volatile memory, wherein at least one of the pages includes a temporary marker; and

omitting the at least one page from the metadata table.

17. The electronic device of claim 16, wherein the control circuitry is further operative to create the metadata table by marking the at least one page as invalid.

18. The electronic device of claim 16, wherein the control circuitry is further operative to create the metadata table by adding valid pages of the non-volatile memory that do not include a temporary marker to the metadata table.

19. The electronic device of claim 16, wherein the metadata tables comprises a table indicating which logical addresses are currently allocated for use by a file system.

20. The electronic device of claim 16, wherein the metadata table comprises a logical-to-physical address mapping.

21. The electronic device of claim 16, wherein the non-volatile memory comprises NAND flash memory.