Scalable SPOR algorithm for flash memories

Patent metadata

Field	Value
Publication number	US-10007451-B2
Application number	US-201615076350-A
Country	US
Kind code	B2
Filing date	Mar 21, 2016
Priority date	Mar 20, 2015
Publication date	Jun 26, 2018
Grant date	Jun 26, 2018

Abstract

Methods of sudden power off recovery may include reading dirty-block meta-pages from memory blocks on a dirty block list, recording mapping in formation in open-block meta-pages, serving host commands by looking up logical block addresses (LBAs) in the dirty-block meta-pages and the open-block meta-pages and when an LBA is not found in the dirty-block meta-pages and the open-block meta-pages, reading new mapping information from a dirty table and saving the new mapping information in host-write meta-pages.

First claim

What is claimed is:

1. A method of sudden power off recovery (SPOR), comprising:
reading dirty-block meta-pages from memory blocks on a dirty block list;
scanning open-blocks and recording mapping information thereof in open-block meta-pages;
serving host commands by looking up logical block addresses (LBAs) in the dirty-block meta-pages and the open-block meta-pages; and
when an LBA is not found in the dirty-block meta-pages or the open-block meta-pages, reading new mapping information from a dirty table and saving the new mapping information in host-write meta-pages, and storing dirty information created by host writes in the host-write meta-pages but not in the dirty table.

2. The method of claim 1 , further comprising:
replaying, in the background, the dirty-table meta-pages, the open-block meta-pages, and the host-write meta-pages in order of old to new such that a valid physical address overwrites an invalid physical address if an LBA occurs multiple times in one meta-page.

3. The method of claim 2 , further comprising serving host commands while performing the replaying step.

4. The method of claim 1 , wherein the looking up is performed from a newest meta-page to an oldest meta-page.

5. A system for performing sudden power off recovery (SPOR), comprising:
a dynamic random access memory (DRAM) including a flash transition layer (FTL) table;
a memory storage suitable for storing dirty-block meta-pages, open-block meta-pages, and host-write meta-pages; and
a controller suitable for:
reading the dirty-block meta-pages from memory blocks on a dirty block list;
scanning open-blocks and recording mapping information thereof in the open-block meta-pages;
serving host commands by looking up logical block addresses (LBAs) in the dirty-block meta-pages and the open-block meta-pages; and
when an LBA is not found in the dirty-block meta-pages or the open-block meta-pages, reading new mapping information from the FTL table and saving the new mapping information in the host-write meta-pages, and storing dirty information created by host writes in the host-write meta-pages but not in the dirty table.

6. The system of claim 5 , wherein the controller is further suitable for preserving space in the DRAM for storing the host-write meta-pages.

7. The system of claim 5 , wherein the controller is further suitable for replaying, in the background, the dirty-table meta-pages, the open-block meta-pages, and the host-write meta-pages in order of old to new such that a valid physical address overwrites an invalid physical address if an LBA occurs multiple times in one meta-page.

8. The system of claim 7 , wherein the controller is further suitable for serving host commands while performing the replaying.

9. The system of claim 5 , wherein the controller is further suitable to perform the looking up from a newest meta-page to an oldest meta-page.

10. A memory device, comprising:
a controller configured to:
read dirty-block meta-pages from memory blocks on a dirty block list;
scanning open-blocks and record mapping information thereof in open-block meta-pages;
serve host commands by looking up logical block addresses (LBAs) in the dirty-block meta-pages and the open-block meta-pages; and
when an LBA is not found in the dirty-block meta-pages or the open-block meta-pages, read new mapping information from a dirty table and save the new mapping information in host-write meta-pages, and store dirty information created by host writes in the host-write meta-pages but not in the dirty table.

11. The memory device of claim 10 , wherein the controller is further configured to replay, in the background, the dirty-table meta-pages, the open-block meta-pages, and the host-write meta-pages in order of old to new such that a valid physical address overwrites an invalid physical address if an LBA occurs multiple times in one meta-page.

12. The memory device of claim 10 , wherein the controller is further configured to serve host commands during replay.

13. The memory device of claim 10 , wherein the looking up is performed from a newest meta-page to an oldest meta-page.

Assignees

• Sk Hynix Inc

Inventors

• Zhang Fan
• Liu Tan
• ROSARIO Constantino

Classifications

• G06F3/0616

  in relation to life time, e.g. increasing Mean Time Between Failures [MTBF] · CPC title

• G06F3/0619 Primary

  in relation to data integrity, e.g. data losses, bit errors · CPC title

• G06F3/0679

  Non-volatile semiconductor memory device, e.g. flash memory, one time programmable memory [OTP] · CPC title

• G06F3/064

  Management of blocks · CPC title

• G06F3/0688

  Non-volatile semiconductor memory arrays · CPC title