News Column

Patent Issued for Systems and Methods for Managing End of Life in a Solid State Drive

June 17, 2014



By a News Reporter-Staff News Editor at Information Technology Newsweekly -- According to news reporting originating from Alexandria, Virginia, by VerticalNews journalists, a patent by the inventors Dreifus, David L. (Clinton, NJ); Warren, Robert W. (Loveland, CO); McKean, Brian (Longmont, CO), filed on January 11, 2012, was published online on June 3, 2014.

The assignee for this patent, patent number 8745449, is LSI Corporation (San Jose, CA).

Reporters obtained the following quote from the background information supplied by the inventors: "The present inventions are related to systems and methods for data storage, and more particularly to systems and methods for end of life management of a solid state drive and/or flash memory device.

"Various approaches for data backup have been developed that vary from simple periodic copying of one storage device to another to more complex backup schemes such as RAID. Such approaches typically rely on redundancy to protect from data loss. In such systems, one or more copies of data are distributed across various storage devices. When a failure of one of the storage devices occurs, a replacement storage device is installed in place of the failed storage device, and the data corresponding to the failed storage device is gathered from redundant sources and written to the replacement storage device. Such approaches offer reasonable data security, but generally require a considerable amount of processing to be performed upon installation of the replacement storage device to replicate the failed storage device. As storage devices may fail at any time, substantial processing may be diverted to rebuilding the failed storage device at a time when such processing causes a noticeable, negative impact on other processes ongoing in a computing environment.

"Hence, for at least the aforementioned reasons, there exists a need in the art for advanced systems and methods for managing the end of life of a failed storage device."

In addition to obtaining background information on this patent, VerticalNews editors also obtained the inventors' summary information for this patent: "The present inventions are related to systems and methods for data storage, and more particularly to systems and methods for end of life management of a solid state drive and/or flash memory device.

"Various embodiments of the present invention provide storage systems that include at least a first flash memory block, a second flash memory block, and a control circuit. The first flash memory block and the second flash memory block are each addressable in the storage system. The control circuit is operable to identify the first flash memory block as partially failed, receive a write request directed to the first flash memory block; and direct the write request to the second flash memory block. In some instances of the aforementioned embodiments, the control circuit is further operable to: receive a read request directed to the first flash memory block; and direct the read request to the first flash memory where the read request is received prior to directing the write request to the second flash memory.

"In some instances of the aforementioned embodiments, the first flash memory block is included in a first solid state drive, the second flash memory block is included in a second solid state drive, and the control circuit is included in a system controller that is communicably coupled to the first solid state drive and the second solid state drive. In some cases, the control circuit receives a write prohibit signal from the first solid state drive. In such cases, identifying the first flash memory block as partially failed is based at least in part on the write prohibit signal, and includes identifying the first solid state drive as partially failed. In particular cases, the control circuit is a first control circuit, the first solid state drive includes a second control circuit, and the second control circuit includes: an unreliable block identification circuit and a partial failure indication circuit. The unreliable block identification circuit is operable to determine that the first flash memory block is unreliable. The partial failure indication circuit is operable to assert the write prohibit signal upon determination that an insufficient number of memory blocks in the first solid state drive remain reliable.

"In various instances of the aforementioned embodiments, the first flash memory block is included in a first solid state drive, the second flash memory block is included in a second solid state drive, and the control circuit is included in a system controller that is communicably coupled to the first solid state drive and the second solid state drive. The control circuit is operable to identify an estimated end of life of the first solid state drive. The control circuit receives a write prohibit signal from the first solid state drive, and identifying the first flash memory block as partially failed is based at least in part on the write prohibit signal. The control circuit is operable to assure that all data from the first solid state drive is transferred to the second solid state drive before the estimated end of life. In some instances of the aforementioned embodiments, the control circuit is a first control circuit, the first solid state drive includes a second control circuit, and the second control circuit includes: an unreliable block identification circuit that is operable to determine that the first flash memory block is unreliable; a partial failure indication circuit that is operable to assert the write prohibit signal upon determination that an insufficient number of memory blocks in the first solid state drive remain reliable; a time stamp circuit that is operable to identify a first point in time when the partial failure indication circuit asserted the write prohibit signal; and an end of life indication circuit that is operable to estimate a second point in time based at least in part on the first point in time. The second point in time is the estimated end of life of the first solid state drive.

"In other instances of the present invention, the control circuit is implemented in a system control unit. The system control unit includes a plurality of interfaces. A first replaceable memory device includes the first flash memory block and is installed in a first of the plurality of interfaces, and a second replaceable memory device includes the second flash memory block and is installed in a second of the plurality of interfaces. The interfaces may be, for example, USB interfaces, and/or DIMM interfaces. In yet other instances of the aforementioned embodiments, the first memory block, the second flash memory block, and the control circuit are implemented in a single flash memory device.

"Other embodiments of the present invention provide methods for managing the end of life of a flash memory device. The methods include providing a first flash memory block and a second flash memory block, determining that the first flash memory block is becoming unreliable, identifying the first flash memory block as read only based at least in part on the determination of unreliability, and mapping the second flash memory block to the first flash memory block. In some instances, the methods further include receiving a write request directed to the first flash memory block; and directing the write request to the second flash memory block. Other instances of the methods include receiving a read request directed to the first flash memory block; and satisfying the read request to the first flash memory block.

"In various instances of the aforementioned embodiments, the first flash memory block is included in a first solid state drive, the second flash memory block is included in a second solid state drive, and the control circuit is included in a system controller that is communicably coupled to the first solid state drive and the second solid state drive. In some such instances, the methods further include estimating an end of life of the first solid state drive; and transferring all data from the first solid state drive to the second solid state drive before the estimated end of life of the first solid state drive. Estimating the end of life of the first solid state drive may include determining a point in time corresponding to the determination of unreliability, and adding a fixed time increment to the point in time to yield the estimated end of life. In yet other instances of the aforementioned embodiments, the methods further include: providing a third flash memory block that includes write-once, read many data; and transferring the write-once, read many data to the first memory block.

"In one or more instances of the aforementioned embodiments, the control circuit is implemented in a system control unit that includes a plurality of interfaces. A first replaceable memory device includes the first flash memory block and is installed in a first of the plurality of interfaces, and a second replaceable memory device includes the second flash memory block and is installed in a second of the plurality of interfaces. The methods may further include removing the first replaceable memory device after data from the first replaceable memory device has been moved to the second replaceable memory device; and installing a third replaceable memory device in the first of the plurality of interfaces.

"This summary provides only a general outline of some embodiments of the invention. Many other objects, features, advantages and other embodiments of the invention will become more fully apparent from the following detailed description, the appended claims and the accompanying drawings."

For more information, see this patent: Dreifus, David L.; Warren, Robert W.; McKean, Brian. Systems and Methods for Managing End of Life in a Solid State Drive. U.S. Patent Number 8745449, filed January 11, 2012, and published online on June 3, 2014. Patent URL: http://patft.uspto.gov/netacgi/nph-Parser?Sect1=PTO1&Sect2=HITOFF&d=PALL&p=1&u=%2Fnetahtml%2FPTO%2Fsrchnum.htm&r=1&f=G&l=50&s1=8745449.PN.&OS=PN/8745449RS=PN/8745449

Keywords for this news article include: LSI Corporation, Information Technology, Information and Data Storage.

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Source: Information Technology Newsweekly


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