Flash-memory device with RAID-type controller

• US 8,321,597 B2
• Filed: 08/03/2011
• Issued: 11/27/2012
• Est. Priority Date: 02/22/2007
• Status: Expired due to Fees

• Current Assignee: Super Talent Technology, Corporation
• Original Assignee: Super Talent Electronics, Inc.
• Inventors: Yu, Frank, Ma, Abraham C., Chen, Shimon
• Primary Examiner(s): Unelus, Ernest
• Application Number:
  US13/197,721
• Publication Number:
  US 20110302358A1
• Time in Patent Office: 482 Days
• Field of Search: 710/22, 710/23, 713/1, 713/2, 713/100
• US Class Current: 710/5
• CPC Class Codes: G06F 11/108 Parity data distribution in semiconductor storages, e.g. in SSD
• CPC Class Codes: G06F 12/0246 in block erasable memory, e.g. flash memory
• CPC Class Codes: G06F 13/28 using burst mode transfer, e.g. direct memory access DMA, cycle steal G06F13/32 takes precedence
• CPC Class Codes: G06F 13/385 for adaptation of a particular data processing system to different peripheral devices
• CPC Class Codes: G06F 21/79 in semiconductor storage media, e.g. directly-addressable memories
• CPC Class Codes: G06F 2212/7208 Multiple device management, e.g. distributing data over multiple flash devices
• CPC Class Codes: G06F 2212/7211 Wear leveling
• CPC Class Codes: G06F 3/0658 Controller construction arrangements
• CPC Class Codes: G06F 3/0679 Non-volatile semiconductor memory device, e.g. flash memory, one time programmable memory [OTP]

Abstract

A smart flash drive has one or more levels of smart storage switches and a lower level of single-chip flash devices (SCFD'"'"'s). A SCFD contains flash memory and controllers that perform low-level bad-block mapping and wear-leveling and logical-to-physical block mapping. The SCFD report their capacity, arrangement, and maximum wear-level count (WLC) and bad block number (BBN) to the upstream smart storage switch, which stores this information in a structure register. The smart storage switch selects the SCFD with the maximum BBN as the target and the SCFD with the lowest maximum WLC as the source of a swap for wear leveling when a WLC exceeds a threshold that rises over time. A top-level smart storage switch receives consolidated capacity, arrangement, WLC, and BBN information from lower-level smart storage switch. Data is striped and optionally scrambled by Redundant Array of Individual Disks (RAID) controllers in all levels of smart storage switches.

Claims

1. A Smart Storage Switch flash device comprising:

a smart storage switch connected upstream to an upstream device and downstream to a plurality of endpoint flash memories;

a flash memory which comprises a plurality of multiple Input/Outputs (I/Os) and a plurality of chip enables;

wherein the smart storage switch comprises;

downstream means for connecting to a plurality of downstream flash memories;

upstream means for connecting to an upstream device;

controller means for dividing upstream data received from the upstream device into a plurality of stripes, each stripe being sent to a different downstream flash memory;

structure register means for storing wear-level counts and bad-block counts of downstream flash memories;

upstream reporting means for reporting a maximum of the wear-level counts to the upstream device and for reporting a maximum of the bad-block counts to the upstream device; and

wear leveling means for using a direct-memory access (DMA) engine to swap physical blocks of two downstream flash memory blocks in two different ones of the downstream flash memories selected using the wear-level counts and bad-block counts stored in the structure register means.

2. The Smart Storage Switch flash device of claim 1 further comprising an upstream interface having a protocol selected from the group consisting of Serial AT-Attachment (SATA), a Peripheral Components Interconnect Express (PCIe) bus, Compact Flash (CF) bus, Universal-Serial-Bus (USB), Secure Digital (SD), e-Multi-Media Card (eMMC) bus, Serial-Attached Small-computer system interface (SAS), and Micro-SD.