Patent Publication Number: US-2017357466-A1

Title: Data storage device and operating method thereof

Description:
CROSS-REFERENCES TO RELATED APPLICATION 
     The present application claims priority under 35 U.S.C. §119(a) to Korean application number 10-2016-0073725, filed on Jun. 14, 2016, in the Korean Intellectual Property Office, which is incorporated herein by reference in its entirety. 
     BACKGROUND 
     1. Technical Field 
     Various embodiments generally relate to a data storage device and, more particularly, to a data storage device including a nonvolatile memory device. 
     2. Related Art 
     Data storage devices store data provided by an external device response to a write request. Data storage devices also provide stored data to an external device in response to a read request. Examples of external devices that use data storage devices include computers, digital cameras, cellular phones and the like. Data storage devices may be embedded in an external device during manufacturing of the external devices or may be fabricated separately and then connected afterwards to an external device. 
     SUMMARY 
     In an embodiment, a data storage device may include: a nonvolatile memory device; and a controller configured to generate a read command based on information on a memory region of the nonvolatile memory device corresponding to a read request and at least one memory region of the nonvolatile memory device corresponding to at least one stand-by read request, wherein the nonvolatile memory device simultaneously reads data stored in the memory region and data stored in the at least one memory region, in response to the read command. 
     In an embodiment, a data storage device may include: a nonvolatile memory device; and a controller configured to determine, based on information on a memory region of the nonvolatile memory device corresponding to a read request and at least one memory region of the nonvolatile memory device corresponding to at least one stand-by read request among a plurality of stand-by read requests, whether the read request is possible to be linked with the at least one stand-by read request, and cause the read request to stand by when the read request is not possible to be linked with the at least one stand-by read request. 
     In an embodiment, a method for operating a data storage device may include: determining, based on information on a memory region corresponding to a read request and at least one memory region corresponding to at least one stand-by read request, whether the read request is possible to be linked with the at least one stand-by read request; and causing the read request to stand by, when the read request is not possible to be linked with the at least one stand-by read request. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The above and other features and advantages of the present invention will become more apparent to those skilled in the art to which the present invention pertains by describing in detail various embodiments thereof with reference to the attached drawings in which: 
         FIG. 1  is a block diagram illustrating a data storage device comprising a nonvolatile memory device coupled to a controller, in accordance with an embodiment of the present invention. 
         FIG. 2A  is a block diagram illustrating a configuration of the nonvolatile memory device shown in  FIG. 1 , in accordance with an embodiment of the present invention. 
         FIG. 2B  is a diagram illustrating, a case where the nonvolatile memory device performs a read operation simultaneously for a plurality of planes. 
         FIG. 2C  is a diagram illustrating a case where the nonvolatile memory device is not possible to perform a read operation simultaneously for planes. 
         FIG. 3  is a diagram illustrating an example of a read request generated by the request generation unit shown in  FIG. 1 . 
         FIG. 4  is a flow chart illustrating a method for operating the data storage device of  FIG. 1 , in accordance with an embodiment of the present invention. 
         FIG. 5  is a block diagram illustrating a solid state drive (SSD), in accordance with an embodiment of the present invention. 
         FIG. 6  is a block diagram illustrating a data processing system comprising a data storage device, in accordance with the embodiment of the present invention. 
     
    
    
     DETAILED DESCRIPTION 
     Hereinafter, a data storage device and an operating method thereof according to the present invention will be described with reference to the accompanying drawings through exemplary embodiments of the present invention. The present invention may, however, be embodied in different forms and should not be construed being limited to the embodiments set forth herein. Rather, these embodiments are provided to describe the present invention in detail to the extent that a person skilled in the art to which the invention pertains can enforce the technical concepts of the present invention. 
     It is to be understood that embodiments of the present invention are not limited to the particulars shown in the drawings, that the drawings are not necessarily to scale, and, in some instances, proportions may have been exaggerated in order to more clearly depict certain features of the invention. While particular terminology is used, it is to be appreciated that the terminology used is for describing particular embodiments only and is not intended to limit the scope of the present invention. The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the present invention. As used herein, singular forms are intended to include the plural forms as well, unless the context dearly indicates otherwise. It will be further understood that the terms “comprises”, “comprising”, “includes”, and “including” when used in this specification, specify the presence of the stated elements and do not preclude the presence or addition of one or more other elements. As used herein, the term “and/or” includes any and all combinations of one or more of the associated listed items. 
     Unless otherwise defined, all terms including technical and la scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which the present invention belongs in view of the present disclosure. It will be further understood that terms, such as those defined in commonly used dictionaries, should be interpreted as having a meaning that is consistent with their meaning in the context of the present disclosure and the relevant art and will not be interpreted in an idealized or overly formal sense unless expressly so defined herein. 
     In the following description, numerous specific details are set forth in order to provide a thorough understanding of the present invention. The present invention may be practiced without some or all of these specific details. In other instances, well-known process structures and/or processes have not been described in detail in order not to unnecessarily obscure the present invention. 
     It is also noted, that in some instances, as would be apparent to those skilled in the relevant art, an element (also referred to as a feature) described in connection with one embodiment may be used singly or in combination with other elements of another embodiment, unless specifically indicated otherwise. 
     Hereinafter, the various embodiments of the present invention will be described in detail with reference to the attached drawings. 
       FIG. 1  is a block diagram illustrating a data storage device  10 , in accordance with an embodiment of the present invention. 
     The data storage device  10  may be configured to store data la provided from an external device (not shown), in response to a write request from the external device. Also, the data storage device  10  may be configured to provide stored data to the external device, in response to a read request from the external device, 
     The data storage device  10  may be implemented in the form of a Personal Computer Memory Card International Association (PCMIA) card, a Compact Flash (CF) card, a smart media card, a memory stick, various multimedia cards (e.g., MMC, eMMC, RS-MMC, and MMC-Micro), various secure digital cards (e,g,, SD, Mini-SD, and Micro-SD), a Universal Flash Storage (UFS), a Solid State Drive (SSD) and the like. 
     The data storage device  10  may include a controller  100  and a nonvolatile memory device  200 . 
     The controller  100  may control the operations of the data storage device  10 . For example, the controller  100  may store data in the nonvolatile memory device  200 , read data from the nonvolatile memory device  200  and output the read data to the external device, according to respective program and read requests received from the external device. 
     The controller  100  may include a request generation unit  110 , a link unit  120 , and a command generation unit  130 . 
     The request generation unit  110  may generate a read request to read data from the nonvolatile memory device  200 . The request generation unit  110  may generate a read request for each of various reasons. For example, the request generation unit  110  may generate read requests to read data requested from the external device, to read data necessary for the operation of the controller  100  and to manage data stored in the nonvolatile memory device  200 . The read request may be generated by specifying the position of a memory region where a read operation is to be performed, in the nonvolatile memory device  200 . 
     The link unit  120  may selectively link read requests generated by the request generation unit  110 . For example, the link unit  120  may determine, based on a memory region corresponding to a read request and memory regions corresponding to one or more read requests waiting to be executed (also referred to hereinafter as stand-by read requests), whether the read request is possible to be linked with the stand-by read requests. When the read request is possible to be linked with the stand-by read requests, the link unit  120  may link the read request with the stand-by read requests. The link unit  120  may determine whether it is possible to perform linking, by determining whether the memory region corresponding to the read request and the memory regions corresponding to the stand-by read requests are possible to be read simultaneously. When a read request is not possible to be linked with at least one stand-by read request, the link unit  120  may delay execution of the read request and cause the read request to become a stand-by read request. 
     The command generation unit  130  may generate a read command based on a plurality of read requests linked by the link unit  120 , and transmit the generated read command to the nonvolatile memory device  200 . 
     That is to say, while the command generation unit  130  may transmit different read commands from respective read requests to the nonvolatile memory device  200 , so that the nonvolatile memory device  200  performs read operations a multitude of times, the command generation unit  130  may generate one read command for a plurality of linked read requests and transmit the generated read command to the nonvolatile memory device  200  so that the nonvolatile memory device  200  reads simultaneously, through one read operation, data corresponding to the plurality of linked read requests. The term “link” means to correlate read requests so as to simultaneously read memory regions corresponding to the respective read requests. 
     Therefore, according to the present embodiment, since read operations which are otherwise to be performed a multitude of times are incorporated into one read operation, the operating speed of the data storage device  10  may be increased, and power consumption of the data storage device  10  may be reduced. 
     According to an embodiment, when it is determined that the number of read requests to be linked is insufficient even though it is determined that the read requests are possible to be linked, the link unit  120  may cause the read requests to stand by. For example, the link unit  120  may determine, based on a maximum number of memory regions capable of being read simultaneously, whether the number of read requests which are currently possible to be linked is sufficient. 
     The nonvolatile memory device  200  may store data received from the controller  100 , and may read stored data and transmit the, read data to the controller  100 , according to control of the controller  100 . 
     The nonvolatile memory device  200  may include any one of a flash memory, such as a NAND flash or a NOR flash, a Ferroelectrics Random Access Memory (FeRAM), a Phase-Change Random Access Memory (PCRAM), a Magnetoresistive Random Access Memory (MRAM), a Resistive Random Access Memory (ReRAM), and the like. 
     While it is illustrated in  FIG. 1  that the data storage device  10  includes only one nonvolatile memory device  200 , it is to be noted that the embodiment is not limited thereto. 
       FIG. 2A  is a block diagram illustrating the nonvolatile memory device  200  shown in  FIG. 1 . 
     The nonvolatile memory device  200  may include a control unit  210 , a data input/output unit  220 , and a data storage unit  230 . 
     The control unit  210  may control the operations of the nonvolatile memory device  200  according to control of the controller  100  of  FIG. 1 . The control unit  210  may read data from a memory region of the data storage unit  230  in response to a read command received from the controller  100 , and transmit the read data to the controller  100 . 
     The data input/output unit  220  may transmit/receive data between the control unit  210  and the data storage unit  230 . The la data input/output unit  220  may include a plurality of buffers BF 0  to BF 3  respectively corresponding to a plurality of planes PN 0  to PN 3 . 
     The data storage unit  230  may include the planes PN 0  to PN 3 . Each of the planes PN 0  to PN 3  may include a plurality of memory blocks BK 0  to BKn. Each of the memory blocks BK 0  to BKn may include a plurality of memory regions MR 0  to mRk. A memory region may be a memory unit by which data is read to a corresponding buffer. For example, the data stored in a selected memory region  201  among the plurality of memory regions MR 0  to MRk may be simultaneously read to the corresponding buffer BF 0 . 
     While it is illustrated in  FIG. 2A  that the data storage unit  230  includes four planes PN 0  to PN 3 , it is to be noted that the embodiment is not limited thereto. 
       FIG. 28  is a diagram illustrating a case where the nonvolatile memory device  200  performs a read operation simultaneously for the planes PN 0  to PN 3 . 
     Referring to  FIG. 2B , the nonvolatile memory device  200  may perform a read operation simultaneously for the planes PN 0  to PN 3 . The nonvolatile memory device  200  may read the data stored in selected memory regions  202  of the planes PN 0  to PN 3 , to the respective buffers BF 0  to BF 3  due to the structural characteristic thereof. For example, the selected memory regions  202  may be memory regions which correspond to the same block address and the same row address in the respective planes PN 0  to PN 3 . For example, the selected memory regions  202  may be memory regions which may be simultaneously accessed through a common word line. 
     Referring again to  FIG. 1 , when memory regions corresponding to a plurality of read requests may be read multaneously as shown in  FIG. 2B , the link unit  120  may link the read requests. As a result, one read command may be generated from the linked read requests, and the memory regions respectively corresponding to the read requests may be read simultaneously as shown in  FIG. 2B , through the one read command. The link unit  120  may determine whether memory regions are possible to be simultaneously read, based on one or more among chip addresses, plane addresses, block addresses and row addresses of the memory regions. 
     While it is illustrated in  FIG. 2B  that a read operation is possibly to be performed simultaneously for all of the four planes PN 0  to PN 3 , it is to be noted that a read operation may be performed simultaneously for only some of the planes PN 0  to PN 3 . 
       FIG. 2C  is a diagram illustrates a case where read requests may not be linked. 
     Referring to  FIG. 2C , selected memory regions  203  to  206  may not correspond to the same block address and the same row address in the respective planes PN 0  to PN 3 . The selected memory regions  203  to  206  may not be coupled to a common word line. In this case, the nonvolatile memory device  200  may not read simultaneously the selected memory regions  203  to  206 , due to the structural characteristic thereof. 
     Referring again to  FIG. 1 , when memory regions corresponding to read requests may not be read simultaneously as shown in  FIG. 2C , the link unit  120  may not link the read requests and cause the read requests to stand by, i.e. delay their executions A stand-by read request may be processed by being linked with new read requests within a predetermined standby time, or may be processed solely without being linked with any read request, when the predetermined standby time passes. 
       FIG. 3  is a diagram illustrating an example of a read request RQ generated by the request generation unit  110  shown in  FIG. 1 . 
     Referring to  FIG. 3 , the request generation unit  110  may generate, when it is necessary to read data from the nonvolatile memory device  200 , the read request RQ which includes a position information  401  on a memory region where the data is stored. The link unit  120  may determine whether it is possible to link read requests, by referring to the position information  401  included in the read request RQ. 
     According to an embodiment, the request generation unit  110  may set a link flag  402  by sorting a read request RQ which should be quickly processed, according to the attribute of the read request RQ. For example, the attribute of the read request RQ may be associated with the use of data to be read. That is, the attribute of the read request RQ may be associated with whether the data is to be transmitted to the external device or the data is to manage the nonvolatile memory device  200 . Otherwise, the attribute of the read request RQ may be associated with the priority of the, read request RQ. 
     In detail, when the read request RQ should be immediately processed by skipping the determination of the link unit  120  the request generation unit  110  may disable the link flag  402 . For example, the request generation unit  110  may set the link flag  402  to “0.” When processing of the read request RQ may be delayed more or less and read requests which are possible to be linked are to be generated successively, the request generation unit  110  may enable the link flag  402 . For example, the request generation unit  110  may set the link flag  402  to “1.” Therefore, the link unit  120  may determine whether the read request RQ is possible to be linked, when the link flag  402  is set to “1.” When the link flag  402  is set to “0,” the link unit  120  may control the command generation unit  130  such that the read request RQ may be processed immediately without being determined in terms of whether it is possible to be linked. 
       FIG. 4  is a flow chart illustrating a method for operating the data storage device  10  of  FIG. 1 . 
     Hereinbelow, the method for operating the data storage device  10  will be described in detail with reference to  FIGS. 1 to 4 . 
     At step S 110 , the request generation unit  110  may generate a read request to read data from the nonvolatile memory device  200 . The request generation unit  110  may generate the read request which includes a position information  401  on a memory region where the data to be read is stored. The request generation unit  110  may set a link flag  402  according to the attribute of the read request. 
     At step S 120 , the link unit  120  may determine whether the link flag  402  is enabled in the read request generated by the request generation unit  110 . When the link flag  402  is enabled, the process may proceed to step S 130 . When the link flag  402  is disabled, the process may proceed to step S 180 . 
     At step S 180 , when the link flag  402  is disabled (the step S 120 , No), the command generation unit  130  may generate a read command based on only the current read request. Namely, the determination of the link unit  120  as to whether the read request is possible to be linked may be skipped. 
     At step S 130 , when the link flag  402  is enabled (the step S 120 , Yes), the link unit  120  may determine, based on information on the memory region corresponding to the read request and one or more memory regions corresponding to one or more stand-by read requests, whether the read request is possible to be linked with at least one of the stand-by read requests. The link unit  120  may determine whether it is possible to link the read request with at least one of the stand-by read requests, by determining whether the memory region corresponding to the read request and a memory region corresponding to the at least one stand-by read request may be read simultaneously. For example, as stated memory regions that are accessible by the same word line may be accessed simultaneously. When the read request is possible to be linked with at least one stand-by read request, the link unit  120  may link the read request with the at least one stand-by read request. When the read request is possible to be linked with at least one stand-by read request (S 130 , Yes), the process proceeds to step S 140 . When the read request is not possible to be linked with at least one stand-by read request (S 130 , No), the process proceeds to step S 150 . 
     At the step S 140 , the link unit  120  may determine whether the number of read requests which are possible to be linked is sufficient. For example, the link unit  120  may determine whether the number of read requests which are possible to be linked is four, based on the number of the planes PN 0  to PN 3  of  FIG. 2A . When the number of read requests is sufficient (S 140 , Yes), the process may proceed to step S 170 . When the number of read requests is not sufficient (S 140 , No), the process may proceed to the step S 150 . 
     At the step S 150 , the link unit  120  may cause the read request to stand by. While the read request is put in stand-by, i.e., a mode in which the read request waits to be executed, read requests which are subsequently generated may be determined as to whether they are possible to be linked with the standby read request and may be linked with the stand-by read request, based on the process shown in  FIG. 4 . 
     At step S 160 , the link unit  120  may determine whether a wait time of the read request (also referred to as a standby time) exceeds a threshold time. When the standby time exceeds the threshold time (S 160 , Yes), the process may proceed to the step S 170 . When the standby time does not exceed the threshold time (S 160  No the process may remain at the step S 160 . 
     At step S 170 , the command generation unit  130  may generate a read command based on the linked read requests. If a read request is not linked with any read request while it is in stand-by mode, the command generation unit  130  may generate a read command based on only the read request. 
     At step S 190 , the command generation unit  130  may transmit the read command to the nonvolatile memory device  200 . Accordingly, when a read command is generated from the linked read requests, the nonvolatile memory device  200  may read data simultaneously from memory regions corresponding to the linked read requests. 
       FIG. 5  is a block diagram illustrating a solid state drive (SSD)  1000  in accordance with an embodiment of the present invention. 
     The SSD  1000  may include a controller  1100  and a storage medium  1200 . 
     The controller  1100  may control data exchange between a host device  1500  and the storage medium  1200 . The controller  1100  may include a processor  1110 , a random access memory (RAM)  1120 , a read only memory (ROM)  1130 , an error correction code (ECC) unit  1140 , a host interface  1150 , and a storage medium interface  1160 . 
     A controller  1100  may operate substantially similarly to the controller  100  shown in  FIG. 1 . The controller  1100  may determine, based on a memory region of a nonvolatile memory device corresponding to a read request and memory regions of the nonvolatile memory device corresponding to one or more stand-by read requests, whether the read request is possible to be linked with at least one of the stand-by read requests. When the read request is possible to be linked with at least one stand-by read request, the controller  1100  may generate a read command based on the read request and the linked at least one stand-by read request. When the read request is not possible to be linked with at least one stand-by read request, the controller  1100  may cause the read request to stand by. 
     The processor  1110  may control the operations of the controller  1100 . For example, the processor  1110  may store data in the storage medium  1200  and read stored data from the storage medium  1200 , according to data processing requests from the host device  1500 . To efficiently manage the storage medium  1200 , the processor  1110  may control the internal operations of the SSD  1000  such as a merge operation, a wear leveling operation, and so forth. 
     The RAM  1120  may store programs and program data to be used by the processor  1110 . The RAM  1120  may temporarily store data received from the host interface  1150  before transferring it to the storage medium  1200 , and may temporarily store data received from the storage medium  1200  before transferring it to the host device  1500 . 
     The ROM  1130  may store program codes to be read by the processor  1110 . The program codes may include commands to be processed by the processor  1110 , for the processor  1110  to control the internal units of the controller  1100 . 
     The ECC unit  1140  may encode data to be stored in the storage medium  1200 , and may decode data read from the storage medium  1200 . The ECC unit  1140  may detect and correct an error occurred in data, according to an FCC algorithm. 
     The host interface  1150  may exchange data processing requests, data, etc. with the host device  1500 . 
     The storage medium interface  1160  may transmit control signals and data to the storage medium  1200 . The storage medium interface  1160  may receive data from the storage medium  1200 . The storage medium interface  1160  may be coupled with the storage medium  1200  through a plurality of channels CH 0  to CHn. 
     The storage medium  1200  may include a plurality of nonvolatile memory devices NVM 0  to NVMn. Each of the plurality of nonvolatile memory devices NVM 0  to NVMn may perform an operation, for example, a write operation and a read operation according to control of the controller  1100 . 
       FIG. 6  is a block diagram illustrating a data processing system  2000  to which a data storage device in accordance with an embodiment is applied. 
     The data processing system  2000  may include a computer, a laptop, a netbook, a smart phone, a digital television (TV), a digital camera, a navigator, etc. The data processing system  2000  may include a main processor  2100 , a main memory device  2200 , a data storage device  2300 , and an input/output device  2400 . The internal units of the data processing system  2000  may exchange data, control signals etc. through a system bus  2500 . 
     The main processor  21   00  may control general operations of the data processing system  2000 . The main processor  2100  may be a central processing unit such as a microprocessor. The main processor  2100  may execute a software such as an operation system, an application, a device driver, and so forth, on the main memory device  2200 . 
     The main memory device  2200  may store programs and program data to be used by the main processor  2100 . The main memory device  2200  may temporarily store data to be transmitted to the data storage device  2300  and the input/output device  2400 . 
     The data storage device  2300  may include a controller  2310  and a storage medium  2320 . The data storage device  2300  may be configured and operate in a manner substantially similar to the data storage device  10  shown in  FIG. 1 . 
     The input/output device  2400  may include a keyboard, a scanner, a touch screen, a screen monitor, a printer, a mouse, or the like, capable of exchanging data with a user, such as receiving a command from the user for controlling the data processing system  2000  or providing a processed result to the user. 
     According to an embodiment, the data processing system  2000  may communicate with at least one server  2700  through a network  2600  such as a local area network (LAN), a wide area network (WAN), a wireless network, and so on. The data processing system  2000  may include, a network interface (not shown) to access the network  2600 . While various embodiments have been described above, it will be understood to those skilled in the art that the embodiments described are examples only. Accordingly, the data storage device and the operating method thereof described herein should not be limited based on the described embodiments. It will be apparent to those skilled in the art that various changes and modifications may be made without departing from the spirit and scope of the invention as defined in the following claims.