Patents by Inventor Kroum Stoev
Kroum Stoev has filed for patents to protect the following inventions. This listing includes patent applications that are pending as well as patents that have already been granted by the United States Patent and Trademark Office (USPTO).
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Publication number: 20240070017Abstract: Aspects of a storage device including a memory and a controller are provided. The controller may determine to perform garbage collection on a superblock. During the garbage collection process, the controller will typically move the superblock into an erase pool for erasing the superblock. However, aspects of the disclosure are directed to a method of measuring a raw bit error rate (RBER) of the superblock prior to erasure. The measured RBER may be used to estimate a data retention time of the storage device and provide the customer with an early warning notification if a health metric of the storage devices reaches a threshold retention time.Type: ApplicationFiled: August 24, 2022Publication date: February 29, 2024Inventors: Lisha WANG, Jinyoung KIM, Andrew Yu-Jen WANG, Jinghuan CHEN, Kroum STOEV
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Patent number: 10338841Abstract: Embodiments of the present disclosure generally relate to SSD management of non-volatile memory blocks for writing multiple data streams. The SSD may include a non-volatile memory organized into a number of superblocks. Each superblock includes a number of streamblocks. In one embodiment, a method of operating the SSD includes receiving a data stream, identifying an open superblock, identifying an available streamblock from the open superblock, and assigning the data stream to the available streamblock from the open streamblock. In another embodiment, a method of operating the SSD includes receiving a first data stream and a second data stream, writing the first data stream to the first streamblock and writing the second data stream to the second streamblock, and calculating a combined XOR parity information for the first streamblock and the second streamblock.Type: GrantFiled: June 27, 2017Date of Patent: July 2, 2019Assignee: WESTERN DIGITAL TECHNOLOGIES, INC.Inventors: Gulzar A. Kathawala, Liam Parker, Kroum Stoev
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Patent number: 10223022Abstract: A set of superblocks can be constructed by a memory controller employing good blocks and partially bad blocks in a plurality of memory access units. Each functional memory access unit among the plurality of memory access units contributes a single block that is a good block or a partially bad block to each superblock. The memory controller can further construct a set of super word line zones within each superblock in the set of superblocks. Each block within a superblock contributes a good word line zone to each super word line zone. Upon encounter of a program error at run time, the super word line zones within the superblock may be modified to continue running the program employing modified super word line zones for the superblock.Type: GrantFiled: January 27, 2017Date of Patent: March 5, 2019Assignee: WESTERN DIGITAL TECHNOLOGIES, INC.Inventors: Meiman Lin Syu, Steven Sprouse, Kroum Stoev, Satish Vasudeva
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Publication number: 20180373431Abstract: Embodiments of the present disclosure generally relate to SSD management of non-volatile memory blocks for writing multiple data streams. The SSD may include a non-volatile memory organized into a number of superblocks. Each superblock includes a number of streamblocks. In one embodiment, a method of operating the SSD includes receiving a data stream, identifying an open superblock, identifying an available streamblock from the open superblock, and assigning the data stream to the available streamblock from the open streamblock. In another embodiment, a method of operating the SSD includes receiving a first data stream and a second data stream, writing the first data stream to the first streamblock and writing the second data stream to the second streamblock, and calculating a combined XOR parity information for the first streamblock and the second streamblock.Type: ApplicationFiled: June 27, 2017Publication date: December 27, 2018Inventors: Gulzar A. KATHAWALA, Liam PARKER, Kroum STOEV
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Patent number: 10109352Abstract: Systems and methods for managing data retention in a solid-state storage system utilizing data retention flag bytes are disclosed. A data storage device includes a non-volatile memory comprising a plurality of non-volatile memory devices and a controller configured to write data to a memory unit of the non-volatile memory array and write a data retention flag value indicating a number of bits of the written data programmed in a first of a plurality of logical states. The controller is further configured to read the data and determine a number of bits having the first of the plurality of logical states in the read data, and determine a difference between the number of bits of the written data programmed in the first logical state and the number of bits having the first logical state in the read data. The difference is used to determine data retention characteristics of the non-volatile memory.Type: GrantFiled: April 10, 2017Date of Patent: October 23, 2018Assignee: Western Digital Technologies, Inc.Inventors: Dengtao Zhao, Yongke Sun, Haibo Li, Jui-Yao Yang, Kroum Stoev
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Publication number: 20180217892Abstract: A set of superblocks can be constructed by a memory controller employing good blocks and partially bad blocks in a plurality of memory access units. Each functional memory access unit among the plurality of memory access units contributes a single block that is a good block or a partially bad block to each superblock. The memory controller can further construct a set of super word line zones within each superblock in the set of superblocks. Each block within a superblock contributes a good word line zone to each super word line zone. Upon encounter of a program error at run time, the super word line zones within the superblock may be modified to continue running the program employing modified super word line zones for the superblock.Type: ApplicationFiled: January 27, 2017Publication date: August 2, 2018Inventors: Meiman Lin Syu, Steven Sprouse, Kroum Stoev, Satish Vasudeva
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Publication number: 20170352423Abstract: Systems and methods for managing data retention in a solid-state storage system utilizing data retention flag bytes are disclosed. A data storage device includes a non-volatile memory comprising a plurality of non-volatile memory devices and a controller configured to write data to a memory unit of the non-volatile memory array and write a data retention flag value indicating a number of bits of the written data programmed in a first of a plurality of logical states. The controller is further configured to read the data and determine a number of bits having the first of the plurality of logical states in the read data, and determine a difference between the number of bits of the written data programmed in the first logical state and the number of bits having the first logical state in the read data. The difference is used to determine data retention characteristics of the non-volatile memory.Type: ApplicationFiled: April 10, 2017Publication date: December 7, 2017Inventors: Dengtao Zhao, Yongke Sun, Haibo Li, Jui-Yao Yang, Kroum Stoev
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Patent number: 9620220Abstract: Systems and methods for managing data retention in a solid-state storage system utilizing data retention flag bytes are disclosed. A data storage device includes a non-volatile memory comprising a plurality of non-volatile memory devices and a controller configured to write data to a memory unit of the non-volatile memory array and write a data retention flag value indicating a number of bits of the written data programmed in a first of a plurality of logical states. The controller is further configured to read the data and determine a number of bits having the first of the plurality of logical states in the read data, and determine a difference between the number of bits of the written data programmed in the first logical state and the number of bits having the first logical state in the read data. The difference is used to determine data retention characteristics of the non-volatile memory.Type: GrantFiled: February 12, 2016Date of Patent: April 11, 2017Assignee: Western Digital Technologies, Inc.Inventors: Dengtao Zhao, Yongke Sun, Haibo Li, Jui-Yao Yang, Kroum Stoev
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Publication number: 20160163392Abstract: Systems and methods for managing data retention in a solid-state storage system utilizing data retention flag bytes are disclosed. A data storage device includes a non-volatile memory comprising a plurality of non-volatile memory devices and a controller configured to write data to a memory unit of the non-volatile memory array and write a data retention flag value indicating a number of bits of the written data programmed in a first of a plurality of logical states. The controller is further configured to read the data and determine a number of bits having the first of the plurality of logical states in the read data, and determine a difference between the number of bits of the written data programmed in the first logical state and the number of bits having the first logical state in the read data. The difference is used to determine data retention characteristics of the non-volatile memory.Type: ApplicationFiled: February 12, 2016Publication date: June 9, 2016Inventors: Dengtao ZHAO, Yongke SUN, Haibo LI, Jui-Yao YANG, Kroum STOEV
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Patent number: 9263136Abstract: Systems and methods for managing data retention in a solid-state storage system utilizing data retention flag bytes are disclosed. A data storage device includes a non-volatile memory comprising a plurality of non-volatile memory devices and a controller configured to write data to a memory unit of the non-volatile memory array and write a data retention flag value indicating a number of bits of the written data programmed in a first of a plurality of logical states. The controller is further configured to read the data and determine a number of bits having the first of the plurality of logical states in the read data, and determine a difference between the number of bits of the written data programmed in the first logical state and the number of bits having the first logical state in the read data. The difference is used to determine data retention characteristics of the non-volatile memory.Type: GrantFiled: November 26, 2013Date of Patent: February 16, 2016Assignee: Western Digital Technologies, Inc.Inventors: Dengtao Zhao, Yongke Sun, Haibo Li, Jui-Yao Yang, Kroum Stoev
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Patent number: 7428124Abstract: A thin film magnetic head includes a slider body having a trailing surface meeting an air-bearing surface at a trailing edge. A magnetic read and write elements are disposed along the trailing surface near the trailing edge. The magnetic write element includes write poles and a coil. A portion of a heating element is disposed in a first general plane beneath the coil and above the magnetic read element. At least one thermally-insulating layer of material having a thermal conductivity of less than about 2.0 W/m-K extends in a second general plane substantially beneath the heating element.Type: GrantFiled: February 9, 2006Date of Patent: September 23, 2008Assignee: Western Digital (Fremont), LLCInventors: Suping Song, Hai Jiang, Charles W. Miller, Kroum Stoev
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Patent number: 7113366Abstract: A thin film electromagnetic head has an inductive transducer with a double-nosed ferromagnetic trailing pole layer. The trailing pole layer has a trailing pole tip disposed adjacent to a media-facing surface, a trailing pole yoke disposed distal to the media-facing surface, and a trailing pole nose disposed between the trailing pole tip and the trailing pole yoke. The media-facing surface extends as a substantially flat surface in all directions from the trailing pole tip. The length of the trailing pole nose may be at least twice as long as the trailing pole tip length. The width of the trailing pole nose can be 10 to 30 times as wide as the trailing pole tip width. An inductive transducer having a double-nosed trailing pole layer provides a higher ratio of on-track to off-track write fields, thereby improving the density with which data can be written to the recording media. Such a double-nosed trailing pole layer can be used in transducers for either longitudinal or perpendicular magnetic recording.Type: GrantFiled: November 7, 2002Date of Patent: September 26, 2006Assignee: Western Digital (Fremont), Inc.Inventors: Yugang Wang, Kroum Stoev, Francis Liu, Yingjian Chen
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Patent number: 6989972Abstract: Magnetoresistive (MR) sensors have leads that overlap a MR structure and distribute current to the MR structure so that the current is not concentrated in small portions of the leads. An electrically resistive capping layer can be formed between the leads and the MR structure to distribute the current. The leads can include resistive layers and conductive layers, the resistive layers having a thickness-to-resistivity ratio that is greater than that of each of the conductive layers. The resistive layers may protect the conductive layers during MR structure etching, so that the leads have broad layers of electrically conductive material for connection to MR structures. The broad leads conduct heat better than the read gap material that they replace, further reducing the temperature at the connection between the leads and the MR structure.Type: GrantFiled: September 30, 2002Date of Patent: January 24, 2006Assignee: Western Digital (Fremont), Inc.Inventors: Kroum Stoev, Mathew Gibbons, Francis Liu, Bogdan M. Simion, Aparna C. Vadde, Jing Zhang, Yiming Huai, Marcos M. Lederman
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Patent number: 6912106Abstract: A method and system for providing a recording head is disclosed. The method and system include providing a first pole, a second pole, a write gap and at least one coil. The write cap separates the first pole from the second pole. The coil(s) include a plurality of turns and is between the first and second poles. The first pole includes a pedestal that has a first portion and a second portion. The first portion includes a high moment electroplated material. The second portion includes a hot seed layer that has a high moment sputtered material. The second portion of the first pole is adjacent to the write gap.Type: GrantFiled: August 6, 2002Date of Patent: June 28, 2005Assignee: Western Digital (Fremont), Inc.Inventors: Yingjian Chen, Qing He, Yugang Wang, Kroum Stoev, Francis Liu, Xiaozhong Dang
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Patent number: 6906894Abstract: A read/write head and method of making the same are used in a data storage system, such as a disk drive, for perpendicular magnetic recording of data. The head employs a two-layer pole design with a main pole made of sputtered high moment magnetic material, and an adjunct pole made of electroplated soft magnetic film. The main pole is used to write data onto the medium, and is formed over the write coil. The adjunct pole is substantially recessed from the air bearing surface and is formed over the main pole. The present head design significantly enhances the magnetic write field, and substantially reduces side-writing that result in accidental erasure of data in adjacent tracks on the magnetic recording medium.Type: GrantFiled: July 29, 2004Date of Patent: June 14, 2005Assignee: Western Digital (Fremont), Inc.Inventors: Yingjian Chen, Xiaozhong Dang, Francis H. Liu, Kroum Stoev, Hai Jiang, Yugang Wang, Xizeng Shi
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Publication number: 20050007696Abstract: A read/write head and method of making the same are used in a data storage system, such as a disk drive, for perpendicular magnetic recording of data. The head employs a two-layer pole design with a main pole made of sputtered high moment magnetic material, and an adjunct pole made of electroplated soft magnetic film. The main pole is used to write data onto the medium, and is formed over the write coil. The adjunct pole is substantially recessed from the air bearing surface and is formed over the main pole. The present head design significantly enhances the magnetic write field, and substantially reduces side-writing that result in accidental erasure of data in adjacent tracks on the magnetic recording medium.Type: ApplicationFiled: July 29, 2004Publication date: January 13, 2005Applicant: Western Digital (Fremont), Inc.Inventors: Yingjian Chen, Xiaozhong Dang, Francis Liu, Kroum Stoev, Hai Jiang, Yugang Wang, Xizeng Shi
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Patent number: 6791793Abstract: A read/write head and method of making the same, are used in a data storage system, such as a disk drive, for perpendicular magnetic recording of data. The head employs a two-layer pole design with a main pole made of sputtered high moment magnetic material, and an adjunct pole made of electroplated soft magnetic film. The adjunct pole is substantially recessed from the air bearing surface. The present head design significantly enhances the magnetic write field, and substantially reduces side-writing that result in accidental erasure of data in adjacent tracks on the magnetic recording medium.Type: GrantFiled: September 14, 2001Date of Patent: September 14, 2004Assignee: Western Digital (Fremont), Inc.Inventors: Yingjian Chen, Xiaozhong Dang, Francis H. Liu, Kroum Stoev, Hai Jiang, Yugang Wang, Xizeng Shi
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Patent number: 6724572Abstract: In one aspect, an inductive transducer is disclosed having a leading pole layer and a leading pole tip, with the pole layer being further removed than the pole tip from a media-facing surface. In another aspect, an inductive transducer is disclosed having a magnetic pedestal disposed between a leading pole layer and a leading pole tip, with at least one of the pedestal and pole layer being further removed than the pole tip from a media-facing surface. In another aspect, a leading pole layer or pedestal may have a surface that slopes away from the media-facing surface with increasing distance forward from the leading pole tip.Type: GrantFiled: February 28, 2002Date of Patent: April 20, 2004Assignee: Western Digital, Inc.Inventors: Kroum Stoev, Yugang Wang, Francis Liu, Yingjian Chen, Xiaozhong Dang