The present invention relates to solid state devices (SSDs), and more particularly to a solid state device (SSD) that includes improved sustained data writing speed.
In a variety of consumer electronics, solid state devices (SSDs) incorporating non-volatile memories (NVMs) are frequently replacing or supplementing conventional rotating hard disk drives for mass storage. These non-volatile memories may include one or more flash memory devices, such as NAND flash memories. These SSDs provide better performance than conventional rotating hard disk drives.
While SSDs provide very fast writing speeds relative to hard disk drives, there is ongoing need to improve the sustained writing speeds of SSDs. One example where writing speed is important is when a host records video data. Hosts, such as digital video cameras, are capable of capturing high density and high-quality videos. Recording high density videos creates a lot of data that has to be stored. Thus, SSDs must have writing speeds that can keep up with the speed at which data is created when the host is recording high density videos, such as 4K video. Otherwise, data that is created by the host, may be lost and not get stored at the SSD. While SSDs can be fabricated with memory cells that have very fast writing speeds, SSDs are not optimized to take full advantage of the maximum writing speeds of these memory cells. These SSDs are often slowed down by the need to perform garbage collection during a writing operation at the SSDs, which reduces the effective writing speed of the SSDs.
An improved SSD is proposed that provides improved sustained maximum writing speeds. Such an improved SSD may be implemented as a memory card that can be used to support real time recording and storing of high density and high-quality videos.
According to an aspect, a data storage apparatus includes a non-volatile memory (NVM) and a controller. The NVM includes a first NVM portion and a second NVM portion. The first NVM portion includes a plurality of first cell types. The first NVM portion includes a first sub-portion that is allocated to store file management data. The second NVM portion includes a plurality of second cell types. The controller is coupled to the NVM. The controller is configured to receive a plurality of payload data and a plurality of file management data; store the plurality of file management data at the first sub-portion of the first NVM portion; and store the plurality of payload data at the NVM.
According to another aspect, a method for operating a data storage apparatus, is described. The method receives data, at a controller coupled to a non-volatile memory (NVM). The NVM includes a plurality of first cell types and a plurality of second cell types. The plurality of first cell types includes a first plurality of addresses allocated to store only file management data; and a second plurality of addresses allocated to store only payload data. The plurality of second cell types includes a third plurality of addresses. The method determines whether the received data includes payload data or file management data. The method stores the received data at one or more addresses from the first plurality of addresses, when the received data includes file management data. The method stores the received data at one or more addresses from the second plurality of addresses, when the received data includes payload data.
According to another aspect, a data storage apparatus includes means for non-volatile storing of data, and means for controlling the means for non-volatile storing of data. The means for non-volatile storing of data includes means for first non-volatile storing of data and means for second non-volatile storing of data. The means for first non-volatile storing of data includes a first plurality of addresses allocated to store file management data; and a second plurality of addresses allocated to store payload data. The means for second non-volatile storing of data, includes a third plurality of addresses. The means for controlling the means for non-volatile storing of data includes: means for receiving data; means for determining whether the received data includes payload data or file management data; means for storing the received data at one or more addresses from the first plurality of addresses, when the received data includes file management data; and means for storing the received data at one or more addresses from the second plurality of addresses, when the received data includes payload data.
The present disclosure provides a data storage device/apparatus. The data storage device/apparatus may be a solid state device (SSD). In one aspect, the SSD may be a memory card. A data storage apparatus, such as an SSD (e.g., memory card) may include a non-volatile memory (NVM) and a controller. The NVM includes a first NVM portion and a second NVM portion. The first NVM portion includes a plurality of first cell types (e.g., plurality of single level cells (SLCs)). The first NVM portion includes a first sub-portion that is allocated to store file management data (e.g., File Allocation Table (FAT) data). The second NVM portion includes a plurality of second cell types (e.g., MLCs, TLCs). The controller is coupled to the NVM. The controller is configured to receive a plurality of payload data and a plurality of file management data; store the plurality of file management data at the first sub-portion of the first NVM portion; and store the plurality of payload data at the NVM.
As will be further described below, in some implementations, an SSD (e.g., memory card) that includes different portions and/or sub-portions for storing different types of data, allows the SSD to provide improved sustained writing speeds and/or a reduction in the amount of data loss. In some implementations, different types of data may be initially routed to different portions and/or sub-portions of the SSD. These different portions and/or sub-portions may be allocated to store only certain types of data. In addition, routing different types of data to different portions of the SSD may prevent garbage collection from being triggered during the writing of data by the SSD when a host is recording video. In some implementations, by avoiding garbage collection when the host may be recording video, the SSD is able to provide sustained high writing speeds that can at least match the speed at which a host is capturing video data, thus providing support for real time recording and storing of video data.
The SSD 102 includes a controller 130, a non-volatile memory (NVM) interface 140 and a non-volatile memory (NVM) 150, such as NAND Flash memory. The controller 130 includes a host interface 120, a processor 132 (or alternatively, an NVM processor 132) and a memory 134 (e.g., random access memory (RAM)). In some implementations, the NVM interface 140 may be implemented within the controller 130. The host interface 120 may be implemented outside of the controller 130.
The controller 130 is configured to control the NVM 150 through the NVM interface 140. The controller 130 may be implemented in a System on Chip (SoC). The processor 132 may be a processor die, and the memory 134 may be a memory die. In some implementations, two or more of the above components (e.g., processor, memory) may be implemented as a single die.
The host interface 120 facilitates communication between the host 104 and other components of the SSD 102, such as the controller 130, the processor 132, and/or the memory 134. The host interface 120 may be any type of communication interface, such as an Integrated Drive Electronics (IDE) interface, a Universal Serial Bus (USB) interface, a Serial Peripheral (SP) interface, an Advanced Technology Attachment (ATA) or Serial Advanced Technology Attachment (SATA) interface, a Small Computer System Interface (SCSI), an IEEE 1394 (Firewire) interface, Non Volatile Memory Express (NVMe), or the like. The host interface 120 of the SSD 102 may be in communication with the SSD interface 160 of the host 104.
The processor 132 is coupled to the RAM memory 134. The processor 132 is also coupled to the NVM 150 via the NVM interface 140. The processor 132 controls operation of the SSD 102. In various aspects, the processor 132 receives commands from the host 104 through the host interface 120 and performs the commands to transfer data between the host 104 and the NVM 150. Furthermore, the processor 132 may manage reading from and writing to the memory 134 for performing the various functions effected by the processor 132 and to maintain and manage cached information stored in memory 134. The processor 132 may receive data through a buffer (not shown) and/or send data through the buffer (not shown). The buffer may be part of the memory 134 or separate from the memory 134.
The processor 132 may include any type of processing device, such as a microprocessor, a microcontroller, an embedded controller, a logic circuit, software, firmware, or the like, for controlling operation of the SSD 102. In some aspects, some or all of the functions described herein as being performed by the processor 132 may instead be performed by another component of the SSD 102. For example, the SSD 102 may include a microprocessor, a microcontroller, an embedded controller, a logic circuit, software, firmware, or any kind of processing device, for performing one or more of the functions described herein as being performed by the processor 132. According to other aspects, one or more of the functions described herein as being performed by the processor 132 are instead performed by the host 104. In still further aspects, some or all of the functions described herein as being performed by the processor 132 may instead be performed by another component such as a processor in a hybrid drive including both non-volatile memory elements and magnetic storage elements.
The memory 134 may be any memory, computing device, or system capable of storing data. For example, the memory 134 may be a random-access memory (RAM), a dynamic random-access memory (DRAM), a double data rate (DDR) DRAM, a static random-access memory (SRAM), a synchronous dynamic random-access memory (SDRAM), a flash storage, an erasable programmable read-only-memory (EPROM), an electrically erasable programmable read-only-memory (EEPROM), or the like. In various embodiments, the processor 132 uses the memory 134, or a portion thereof, to store data during the transfer of data between the host 104 and the NVM 150. For example, the memory 134 or a portion of the memory 134 may be a cache memory. The memory 134 may be a shared memory that is accessible by different components, such the processor 132.
The NVM 150 receives data from the processor 132 via the NVM interface 140 and stores the data. The NVM 150 may be any type of non-volatile memory, such as a flash storage system, a NAND-type flash memory, a solid state storage device, a flash memory card, a secure digital (SD) card, a universal serial bus (USB) memory device, a CompactFlash card, a SmartMedia device, a flash storage array, or the like. In one aspect, where the NVM 150 includes a flash storage system, the NVM interface 140 may be a flash memory interface.
As will be further described below, the NVM 150 may include a first NVM portion and a second NVM portion. The second NVM portion may include a first sub-portion and a second sub-portion. The NVM 150 may include different cell types. Examples of cell types include a single level cell (SLC), a multi-level cell (MLC), and a triple level cell (TLC). These and other cell types are further described below.
The host 104 may be any device and/or system having a need for data storage or retrieval and a compatible interface for communicating with the SSD 102. For example, the host 104 may include a computing device, a personal computer, a portable computer, a workstation, a server, a router, a network device, a personal digital assistant, a digital camera, a digital phone, a digital video camera, or combinations thereof. The host 104 can include several hosts. The host 104 may be a separate (e.g., physically separate) device from the SSD 102. In some embodiments, the host 104 includes the SSD 102. For example, the SSD 102 may be a memory card that is inserted in the host 104. In other embodiments, the SSD 102 is remote with respect to the host 104 or is contained in a remote computing system communicatively coupled with the host 104. For example, the host 104 may communicate with the SSD 102 through a wireless communication link.
The host 104 may include an SSD interface 160, a processor 170, a memory 180 (e.g., random access memory (RAM)). The SSD interface 160 is coupled to the processor 170. The processor 170 is coupled to the memory 180.
The SSD interface 160 facilitates communication between the SSD 102 and other components of the host 104, such as the processor 170 and the memory 180. The host 104 provides commands to the SSD 102 for transferring data between the host 104 and the SSD 102. For example, the host 104 may provide a write command to the SSD 102 for writing data to the SSD 102, or a read command to the SSD 102 for reading data from the SSD 102. The SSD 102 may provide a response, to the write command or the read command, to the host 104.
The processor 170 may be similar to the processor 132. For example, the processor 170 may include any type of processing device, such as a microprocessor, a microcontroller, an embedded controller, a logic circuit, software, firmware, or the like, for controlling operation of the host 104. In some aspects, some or all of the functions described herein as being performed by the processor 170 may instead be performed by another component of the host 104. For example, the host 104 may include a microprocessor, a microcontroller, an embedded controller, a logic circuit, software, firmware, or any kind of processing device, for performing one or more of the functions described herein as being performed by the processor 170. According to other aspects, one or more of the functions described herein as being performed by the processor 170 are instead performed by the SSD 102. In still further aspects, some or all of the functions described herein as being performed by the processor 170 may instead be performed by another.
The memory 180 may be any memory, computing device, or system capable of storing data. For example, the memory 180 may be a random-access memory (RAM), a dynamic random-access memory (DRAM), a double data rate (DDR) DRAM, a static random-access memory (SRAM), a synchronous dynamic random-access memory (SDRAM), a flash storage, an erasable programmable read-only-memory (EPROM), an electrically erasable programmable read-only-memory (EEPROM), or the like. In various embodiments, the processor 170 uses the memory 180, or a portion thereof, to store data. For example, the memory 180 or a portion of the memory 180 may be a cache memory. The memory 180 may be a shared memory that is accessible by different components, such the processor 170.
In some implementations, the first NVM portion 210 includes a first plurality of cells (e.g., memory cells) that has a first maximum writing speed, and the second NVM portion includes a second plurality of cells that has a second maximum writing speed that is lower than the first maximum writing speed. For example, the second plurality of cells may include MLCs and/or TLCs may have a second maximum writing speed that is lower than the first maximum writing speed of SLCs (which is an example of the first plurality of cells). In another example, the first plurality of cells may be MLCs and the second plurality of second cells may be TLCs, and the TLCs have a second maximum writing speed that is lower than the first maximum writing speed of the MLCs. In some implementations, the first plurality of cells and the second plurality of cells may be the same type of cells that have different maximum writing speeds. For example, the first plurality of cells may be a first plurality of SLCs with a first maximum writing speed, and the second plurality of cells may be a second plurality of SLCs with a second maximum writing speed.
The first NVM portion 210 includes a first sub-portion 212 and a second sub-portion 214. In some implementations, the first sub-portion 212 may include a subset of dies from the first dies of the first NVM portion 210. In some implementations, the first sub-portion 212 may be a physical partition and/or a logical partition of the first NVM portion 210. In some implementations, the first sub-portion 212 may include a first plurality of physical addresses from the first physical addresses of the first NVM portion 210. In some implementations, the second sub-portion 214 may include a subset of dies from the first dies of the first NVM portion 210. In some implementations, the second sub-portion 214 may be a physical partition and/or a logical partition of the first NVM 210. In some implementations, the second sub-portion 214 may include a second plurality of physical addresses from the first physical addresses of the first NVM portion 210.
In some implementations, different types of data may be stored (e.g., initially stored) in different portions of the NVM 150 to provide an SSD 102 that is capable of sustained high performance writing speeds. Moreover, storing different types of data in different portions may provide reduced data loss and/or reduced errors in data that is stored in the SSD 102.
Having described an SSD that includes several portions, schemes and methods for routing and storing different types of data to different portions of the SSD will now be described below.
As the data is being received by the SSD 102, the SSD 102 may direct different types of data to be stored in different portions of the NVM 150. Thus, in some implementations, the data that is received is routed or directed to specific portions and/or sub-portions of the NVM 150, based on pre-defined routing schemes.
The destination addresses, which are represented as T1, T2, etc., are logical addresses that may be specified by the host 104. A translation table (e.g., flash translation table (FTL)) may be used by the SSD 102 to convert the logical address into physical addresses of the NVM 150. An example of how a translation table may operate is further illustrated and described below in
As will be further described below, these routing schemes allow the SSD 102 to provide sustained high-performance writing speeds during a recording of video (e.g., high density (HD) video, 4K video) by the host 104. This enables high quality video to be recorded and stored in real time. Moreover, these routing schemes reduce the amount of data that is loss and/or errors in data.
As mentioned above, the SSD 102 may use a translation table to determine where to store the different types of data.
The translation table 400 may include instructions and/or commands that convert a logical address to a physical address in the SSD 102. The translation table 400 may manage the NVM 150 in terms of blocks (e.g., memory blocks) for ease of management. Every block has a physical address which may be pre-determined or pre-defined in the NVM 150. The assignment of the logical address to the physical address may be done at flash management unit (FMU) level, which is generally 4K. The translation table 400 may assign the next available physical memory to the incoming logical address. Once the physical address is assigned to a logical address, the physical address is stored in the translation table 400. Whenever the data in a physical address X, is moved to a physical address Y, the translation table 400 is updated with the updated physical address for the logical address. Every I/O operation that requires a physical address for a user data may use the translation table 400.
Thus, as shown in
In some implementations, reserving and/or allocating physical addresses or blocks of physical addresses of the NVM 150 for storing only a particular type of data may be done during and/or after a formatting of the NVM 150. In some implementations, formatting or reformatting the NVM 150 may result in different physical addresses or blocks of physical addresses to be reserved and/or allocated to store a particular type of data.
In some implementations, the above technical advantage is achievable for the following reasons. One, the NVM 150 is divided into different portions, sub-portions, partitions (e.g., physical partition, logical partitions) or combinations thereof, where some of the portions and/or sub-portions may have different properties (e.g., storage capabilities per cell, writing speeds, reliability). Some of these different portions are made of different configurations of cells that store data. For example, the first NVM portion 210 may include SLCs, while the second NCM portion 220 may include MLCs and/or TLCs. An SLC is a memory cell that can store a single bit of data per cell. An SLC is faster than other cells at storing and retrieving data, is more reliable (e.g., less error prone) and longer lasting than other cells. However, an SLC is more expensive than other cells. An MLC is a memory cell that can store multiple bits of data per cell (e.g., two or more bits of data per cell). An MLC is not a fast as an SLC; is more error prone than an SLC, but an MLC is cheaper to fabricate than an SLC. An TLC is a memory cell that can store 3 bits of data per cell. An TLC cell is cheaper to fabricate than an SLC, but is not as reliable (e.g., more error prone) than an SLC. Since speed and reliability are important when initially storing information, the first NVM portion 210 includes a plurality of SLCs. Thus, when data is initially stored, a routing scheme will first attempt to store data at the first NVM portion 210, which is faster at storing data than the second NVM portion 220.
Second, the NVM 150 is divided in such a way that garbage collection may not be needed to be performed when writing to the NVM 150 during a video recording by the host 104. In some implementations, to account for a worst-case scenario, about 1 percent (%) or more of the total capacity of the NVM 150 is reserved for the first NVM portion 210. In some implementations, about 1 percent (%) or more of the total capacity of the NVM 150 is reserved for the first sub-portion 212 of the first NVM portion 210. In some implementations, saving about 1 percent or more of the total storage for storing FAT data is enough so that garbage collection is not triggered during video recording by the host 104. This is because in a worst-case scenario, FAT data will not be more than about 1 percent of the total audio video data.
The assumption in
In
While the routing schemes described in the present disclose may not trigger garbage collection (e.g., foreground garbage collection) when the writing of data is performed during a video recording by the host 104, the SSD 102 may nonetheless perform garbage collection (e.g., background garbage collection) when the host 104 is idle (e.g., not video recording, not storing data at the SSD).
Another technical advantage of the described routing scheme is the reduction in data loss.
The above issue can be reduced by storing the FAT data in a portion of the NVM 150 that includes SLCs, which are faster and more reliable than other memory cells, like MLCs and TLCs. Thus, by redirecting and routing FAT data to the first sub-portion 212, which includes a plurality of SLCs, the SSD 102 is reducing the likelihood of data loss and/or errors in data.
Having described various configurations of the NVM 150 and technical advantages of the configurations of the NVM 150 and the routing schemes, various methods for writing and storing data at the SSD 102 will now be described below.
The method receives (at 1002) data. The data may be received from a host (e.g., 104) through the host interface 120. The data may include various types of data, such as file management data (e.g., FAT data) and audio video data.
The method determines (at 1004) the type of data that has been received. Data can include payload data (e.g., audio video data) and file management data, such FAT data. Data can also include data associated with a Force Unit Access (FUA) command and/or a read modify write (RMW) command. Different implementations may use different methods for determining the type of data that is received. For example, the SSD 102 may identify data received from the host 104 as being FAT data using various methods. In some implementations, data may be identified as FAT data based on the logical block addressing (LB A) and/or the command size (e.g., CMD size) of the data. For example, data that is associated with a particular pre-defined logical address may be considered FAT data. In one example, data that is below a certain threshold size may be considered FAT data. In one example, data that is associated with a certain command may be considered FAT data. In some implementations, the SSD 102 may use one or more of the above methods for determining whether data is FAT data. In some implementations, combinations of the above methods may be used to determine whether data is FAT data. However, it is noted that the SSD 102 may use other methods for determining that data is FAT data. For example, the method may determine that data is payload data or FAT data by looking at the header of the data and/or looking at the size of the data. The host 104 may specify the type of data that is transmitted to the SSD 102. In some implementations, when the SSD 102 determines that data is not FAT data, the SSD 102 may determine that the data is payload data.
The method stores (at 1006) the received data at an appropriate location based (i) on the type of data received and (ii) how much space or capacity is available at one or more of the portions and/or sub-portions of the NVM 150.
For example, when the received data is FAT data, the method 1000 may determine whether the first sub-portion 212 is full or if there is enough available space at the first sub-portion 212. When there is available space (e.g., when the first sub-portion 212 is not full), the method 1000 may store the FAT data at the first sub-portion 212. However, when the first sub-portion 212 is full or there is not enough available space at the first sub-portion 212, the method 1000 may direct the FAT data to be stored at the second NVM portion 220.
In another example, when the received data is payload data, the method 1000 may determine whether the second sub-portion 214 is full or if there is enough available space at the second sub-portion 214. When there is available space (e.g., when the second sub-portion 214 is not full), the method may store the payload data at the second sub-portion 214. However, when the second sub-portion 214 is full or there is not enough available space at the second sub-portion 214, the method 1000 may direct the payload data to be stored at the second NVM portion 220.
In yet another example, when the received data is associated with a FUA command or a RMW command, the method 1000 may determine whether the first sub-portion 212 is full or if there is enough available space at the first sub-portion 212. When there is available space (e.g., when the first sub-portion 212 is not full), the method 1000 may store the data associated with the FUA command or the RMW command at the first sub-portion 212. However, when the first sub-portion 212 is full or there is not enough available space at the first sub-portion 212, the method 1000 may direct the data associated with the FUA command or the RMW command to be stored at the second NVM portion 220.
In some implementations, the first sub-portion 212 and/or the second sub-portion 214 may be full or near capacity, and the method 1000 may perform (at 1008) a foreground garbage collection (e.g., garbage collection performed while host is recording video) to free up space in the first sub-portion 212 and/or the second sub-portion 214. For example, the method 1000 may perform foreground garbage collection when the data that is received is associated with the FUA command or the RMW command, and space (e.g., physical addresses) in the first sub-portion 212 that are allocated for storing data associated with the FUA command or the RMW command is full or near capacity.
The method determines (at 1010) whether there is more data. If so, the method proceeds back to receive (at 1002) more data. If not, the method 1000 may determine that the host is idle, and the method 1000 may perform (at 1012) a background garbage collection. As mentioned above, background garbage collection may occur when the host is idle (e.g., not recording video, not capturing image). Garbage collection may include moving or relocating data (e.g., FAT data, payload data) from a first physical address to a second physical address. The second physical address may be located within the same sub-portion or portion of the first physical address, or the second physical address can be located in a different sub-portion or different portion of the first physical address. Examples of garbage collections are described in
The method receives (at 1102) data. The data may be received from a host (e.g., 104) through the host interface 120.
The method determines (at 1104) the type of data that has been received. Data can include payload data (e.g., audio video data) and file management data, such as FAT data. Examples of how to determine the type of data are described in
When the received data is file management data (e.g., FAT data), the method 1100 proceeds to determine (at 1106) whether the first sub-portion 212 is full or if there is enough available space at the first sub-portion 212. When there is available space (e.g., when the first sub-portion 212 is not full), the method 1100 stores (at 1108) the file management data at the first sub-portion 212, which may include storing data at one or more addresses from a first plurality of addresses of the first NVM portion 210. When the first sub-portion 212 is full or there is not enough available space at the first sub-portion 212, the method proceeds to store (at 1110) the file management data at the second NVM portion 220, which may include storing data at one or more addresses from a third plurality of addresses from the second NVM portion 220.
When the received data is payload data (e.g., audio video data), the method 1100 proceeds to determine (at 1112) whether the second sub-portion 214 is full or if there is enough available space at the second sub-portion 214. When there is available space (e.g., when the second sub-portion 214 is not full), the method 1100 stores (at 1114) the payload data at the second sub-portion 214, which may include storing data at one or more addresses from a second plurality of addresses of the first NVM portion 210. When the second sub-portion 214 is full or there is not enough available space at the second sub-portion 214, the method proceeds to store (at 1116) the payload data at the second NVM portion 220, which may include storing data at one or more addresses from a third plurality of addresses from the second NVM portion 220.
After storing (at 1108, 1110, 1114, 1116), the method 1100 determines (at 1118) whether there is more data. If so, the method proceeds back to receive (at 1102) more data. If not, the method 1100 may end or wait for more data.
Having described various configurations of an NVM and methods for routing different types of data to different portions of the NVM, a specific example of an SSD will now be described below.
In some implementations, this allocation of storage space enables the SSD to provide a full card write of the SSD without having to perform garbage collection. In some implementations, this configuration assumes that the FAT data will not take up more than 1 percent of the payload data. Thus, if the SSD is capable of storing about 512 GB of data, then this configuration assumes that no more than about 5 GB is needed for the FAT data. However, different implementations may make different assumptions for the worst-case scenario and thus may utilize a different allocation of storage space for the SSD.
Background garbage collection may be performed (at 1330), when the host 104 is idle (e.g., not recording video) or when no data is received by the SSD 102. Background garbage collection may move or relocate data from blocks of the second sub-portion 214 and/or the first sub-portion 212 to blocks of the second NVM portion 220. In some implementations, when garbage collection is performed, blocks that are freed may be added (at 1340) to a list of free blocks 1300 that keeps tracks of which blocks are available to store data. Similarly, when blocks are freed (e.g., delete a file), the freed blocks may be added to the list of free blocks 1300. The list of free blocks 1300 helps the SSD 102 manage and determine where data can be stored. The list of free blocks 1300 may also help the SSD 102 ensure that one block is not storing data more often than other blocks.
While the above description contains many specific embodiments of the invention, these should not be construed as limitations on the scope of the invention, but rather as examples of specific embodiments thereof. Accordingly, the scope of the invention should be determined not by the embodiments illustrated, but by the appended claims and their equivalents. The term “about ‘X’”, or “approximately ‘X’”, as used in the disclosure shall mean within 10 percent of the ‘value X’. For example, a value of about 1 or approximately 1, would mean a value in a range of 0.9-1.1.
The various features and processes described above may be used independently of one another, or may be combined in various ways. All possible combinations and sub-combinations are intended to fall within the scope of this disclosure. In addition, certain method, event, state or process blocks may be omitted in some implementations. The methods and processes described herein are also not limited to any particular sequence, and the blocks or states relating thereto can be performed in other sequences that are appropriate. For example, described tasks or events may be performed in an order other than that specifically disclosed, or multiple may be combined in a single block or state. The example tasks or events may be performed in serial, in parallel, or in some other suitable manner. Tasks or events may be added to or removed from the disclosed example embodiments. The example systems and components described herein may be configured differently than described. For example, elements may be added to, removed from, or rearranged compared to the disclosed example embodiments.
Number | Name | Date | Kind |
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20080126680 | Lee | May 2008 | A1 |
20160110126 | Lee | Apr 2016 | A1 |
Number | Date | Country | |
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20200150873 A1 | May 2020 | US |