News Column

Patent Issued for Data Search Using Bloom Filters and NAND Based Content Addressable Memory

September 9, 2014

By a News Reporter-Staff News Editor at Journal of Technology -- According to news reporting originating from Alexandria, Virginia, by VerticalNews journalists, a patent by the inventors Li, Yan (Milpitas, CA); Sprouse, Steven T. (San Jose, CA), filed on March 14, 2013, was published online on August 26, 2014.

The assignee for this patent, patent number 8817541, is SanDisk Technologies Inc. (Plano, TX).

Reporters obtained the following quote from the background information supplied by the inventors: "Content addressable memories, also known as associative memories, are different from standard memories in the way that data is addressed and retrieved. In a conventional memory, an address is supplied and the data located at this specified address is retrieved. In contrast, in a content addressable memory (CAM), data is written as a key-data pair. To retrieve the data, a search key is supplied and all the keys in the memory are searched for a match. If a match is found, the corresponding data is retrieved.

"Content Addressable Memories, or CAMs, can be implemented in several ways. In one sort of embodiment, a CAM is implemented using a conventional memory and an associated CPU which searches through the memory to find a matching key. The keys in the memory may be sorted, in which case a binary search can be used; or they can be unsorted, in which case they are usually hashed into buckets and each bucket is searched linearly. A CAM can also be implemented as a semiconductor memory, where every memory location contains an n-bit comparator. When an n-bit key is provided, each entry in the CAM will compare the search key with the entry's key, and signal a match if the two are equal."

In addition to obtaining background information on this patent, VerticalNews editors also obtained the inventors' summary information for this patent: "Aspects presented here concern a method of operating a non-volatile memory system. A plurality of bloom filters, each generated from a corresponding set of search elements, are stored on a search matrix formed of one or more non-volatile memory arrays of the memory system. The memory arrays are of a NAND type architecture and the bloom filters are stored oriented along the arrays' bit lines. For each of the bloom filters, storing a corresponding data element is stored in a first non-volatile memory section of the memory system. The control circuitry of the memory system maintains a correspondence between the location of the bit lines of the search matrix upon which the bloom filters are stored and the location at which the corresponding data elements are store in the first non-volatile memory section.

"Various aspects, advantages, features and embodiments of the present invention are included in the following description of exemplary examples thereof, which description should be taken in conjunction with the accompanying drawings. All patents, patent applications, articles, other publications, documents and things referenced herein are hereby incorporated herein by this reference in their entirety for all purposes. To the extent of any inconsistency or conflict in the definition or use of terms between any of the incorporated publications, documents or things and the present application, those of the present application shall prevail."

For more information, see this patent: Li, Yan; Sprouse, Steven T.. Data Search Using Bloom Filters and NAND Based Content Addressable Memory. U.S. Patent Number 8817541, filed March 14, 2013, and published online on August 26, 2014. Patent URL:

Keywords for this news article include: Legal Issues, SanDisk Technologies Inc., Technology.

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Source: Journal of Technology

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