SYSTEMS AND METHODS FOR AVERAGING ERROR RATES IN NON-VOLATILE DEVICES AND STORAGE SYSTEMS

• US 20120066441A1
• Filed: 11/21/2011
• Published: 03/15/2012
• Est. Priority Date: 10/15/2009
• Status: Active Grant

• Current Assignee: Avago Technologies International Sales Pte Limited (Broadcom, Inc.)
• Original Assignee: DensBits Technologies Ltd. (Broadcom, Inc.)
• Inventors: Weingarten, Hanan
• Granted Patent: US 8,730,729 B2
• Time in Patent Office: Days
• US Class Current: 711/103
• CPC Class Codes: G06F 11/1068 in sector programmable memories, e.g. flash disk G06F11/1072 takes precedence
• CPC Class Codes: G06F 12/0246 in block erasable memory, e.g. flash memory
• CPC Class Codes: G06F 2212/1032 Reliability improvement, data loss prevention, degraded operation etc
• CPC Class Codes: G06F 2212/7202 Allocation control and policies
• CPC Class Codes: G06F 2212/7208 Multiple device management, e.g. distributing data over multiple flash devices
• CPC Class Codes: G11C 16/0483 comprising cells having several storage transistors connected in series
• CPC Class Codes: H04L 1/203 Details of error rate determination, e.g. BER, FER or WER

Abstract

A system for storing a plurality of logical pages in a set of at least one flash device, each flash device including a set of at least one erase block, the system comprising apparatus for distributing at least one of the plurality of logical pages over substantially all of the erase blocks in substantially all of the flash devices, thereby to define, for at least one logical page, a sequence of pagelets thereof together including all information on the logical page and each being stored within a different erase block in the set of erase blocks; and apparatus for reading each individual page from among the plurality of logical pages including apparatus for calling and ordering the sequence of pagelets from different erase blocks in the set of erase blocks.

Claims

1. A flash memory accessory device operative in conjunction with a data source supplying a stream of logical pages including data and a flash memory system including a multiplicity of physical pages, the accessory system comprising:

logical page distributing apparatus for distributing data from at least one logical page in said stream between at least two of said multiplicity of physical pages.

2. The device according to claim 1 wherein said multiplicity of physical pages is partitioned into a plurality of erase sectors each having physical pages, wherein the physical pages within an individual erase sector can only be erased in unison, wherein said apparatus for distributing distributes data from at least one logical page in said stream between physical pages within a single erase sector.

3. The device according to claim 1 wherein said multiplicity of physical pages is partitioned into at least first and second erase sectors each having physical pages, wherein the physical pages within each erase sector can only be erased in unison, wherein said apparatus for distributing distributes information from at least one logical page in said stream between at least a first physical page within the first erase sector and at least a second physical page within the second erase sector.

4. The device according to claim 1 wherein said flash memory system comprises at least first and second flash memory banks which are accessible in parallel and wherein said apparatus for distributing distributes information from at least one logical page in said stream between at least a first physical page within the first flash memory bank and at least a second physical page within the second flash memory bank.

5. The device according to claim 4 wherein said first and second physical pages are read from simultaneously when it is desired to access therefrom, a logical page stored therewithin.

6. The device according to claim 4 wherein said first and second physical pages are written to simultaneously when it is desired to store a logical page therewithin.

7. The device according to claim 1 wherein said logical page distributing apparatus is operative to distribute at least a pagelet within at least a logical page onto a physical page determined by computing a predetermined function of a logical address received from a controller

8. A device according to claim 1 wherein said page-distributing apparatus comprises apparatus for partitioning, for at least one set of logical pages, each of several logical pages in said set into pagelets and apparatus for grouping pagelets from said several logical pages together using a predetermined pagelet grouping scheme to form a multi-origin physical page-ful of data containing pagelets originating from more than one logical page.

9. A device according to claim 8 wherein said pagelet grouping scheme comprises a pagelet permutation scheme.

10. A device according to claim 9 wherein said at least one set of logical pages comprises a plurality of sets of logical pages and wherein said pagelet permutation scheme is characterized in that not all of said plurality of sets of logical pages are permuted in the same way.

11. Apparatus according to claim 1 wherein said set of flash devices includes a set of at least one bank of flash devices, each bank in said set of banks including at least one flash device.

12. A system for storing a plurality of logical pages in a set of at least one flash device, each flash device including a set of at least one erase block, the system comprising:

apparatus for distributing at least one of said plurality of logical pages over substantially all of said erase blocks in substantially all of said flash devices, thereby to define, for at least one logical page, a sequence of pagelets thereof together including all information on the logical page and each being stored within a different erase block in said set of erase blocks; and

apparatus for reading each individual page from among said plurality of logical pages including apparatus for calling and ordering said sequence of pagelets from different erase blocks in said set of erase blocks.

13. A method for facilitating interaction between a data source supplying a stream of logical pages including data and a flash memory system including a multiplicity of physical pages, the method comprising:

distributing data from at least one logical page in said stream between at leak two of said multiplicity of physical pages.

14. A method for storing a plurality of logical pages in a set of at least one flash device, each flash device including a set of at least one erase blocks, the method comprising:

distributing at least one of said plurality of logical pages over substantially all of said erase blocks in substantially all of said flash devices;

thereby to define, for at least one logical page, a sequence of pagelets thereof together including all information on the logical page and each being stored within a different erase block in said set of erase blocks; and

reading each individual page from among said plurality of logical pages including apparatus for calling and ordering said sequence of pagelets from different erase blocks in said set of erase blocks.