US20140108708A1 - Raid configuration in a flash memory data storage device - Google Patents

Abstract

A method of storing data in a flash memory data storage device that includes a plurality of memory chips is disclosed. The method includes determining a number of memory chips in the data storage device, defining, via a host coupled to the data storage device, a first partition of the data storage device, where the first partition includes a first subset of the plurality of memory chips and defining a second partition of the data storage device via a host coupled to the data storage device, where the second partition includes a second subset of the plurality of memory chips. First data is written to the first partition while reading data from the second partition, and first data is written to the second partition while reading data from the first partition.

Description

CROSS REFERENCE TO RELATED APPLICATIONS
• This application claims priority to, and is a continuation of, U.S. Nonprovisional patent application Ser. No. 12/537,748, filed on Aug. 7, 2009, entitled “Raid Configuration in a Flash Memory Data Storage Device”, which, in turn, claims priority to U.S. Provisional Application No. 61/167,709, filed Apr. 8, 2009, entitled “Data Storage Device” and U.S. Provisional Application No. 61/187,835, filed Jun. 17, 2009, entitled “Partitioning and Striping in a Flash Memory Data Storage Device,” the disclosures of which are hereby incorporated by reference in their entirety.
TECHNICAL FIELD
• This description relates to a data storage device.
BACKGROUND
• Data storage devices may be used to store data. A data storage device may be used with a computing device to provide for the data storage needs of the computing device. In certain instances, it may be desirable to store large amounts of data on a data storage device. Also, it may be desirable to execute commands quickly to read data from and to write data to the data storage device.
SUMMARY
• In a first general aspect, a method of storing data in a flash memory data storage device that includes a plurality of memory chips is disclosed. The method includes determining a number of memory chips in the data storage device, defining, via a host coupled to the data storage device, a first partition of the data storage device, where the first partition includes a first subset of the plurality of memory chips and defining a second partition of the data storage device via a host coupled to the data storage device, where the second partition includes a second subset of the plurality of memory chips. First data is written to the first partition while reading data from the second partition, and first data is written to the second partition while reading data from the first partition.
• Implementations can include one or more of the following features. For example, second data can be written to the first partition, while reading data, and second data can be written to the second partition while reading data from the first partition, and for N=3rd to at least 10th, or at least 100th, or at least 1000th: N data can be written to the first partition, while reading data from the second partition, and N data can be written to the second partition while reading data from the first partition.
• Determining a number memory chips in the data storage device can include transmitting information from the data storage device to the host indicating the number of memory chips in the data storage device, and the transmitted information can include information about the physical architecture of the data storage device, including information about connections between particular memory chips and particular channels of the data storage device. An address location in the data storage device to which to write data from the host, can be defined in the host, where the address location specifies that the data be written to a specific one of the plurality of memory chips.
• The data storage device can include a plurality of physical channels for communication of data between the host and the plurality of memory chips, with each channel being operably connected to a different plurality of the memory chips, and the method further include determining a number of the physical channels, determining a first subset of the number channels, where channels of the first subset of channels are operably connected only to memory chips of the first subset of memory chips, and determining a second subset of the number of channels, where channels of the second subset of channels are operably connected only to memory chips of the second subset of memory chips. An address location in the data storage device to which to write data from the host can be defined in the host, where the address location specifies that the data be written to a specific one of the plurality of memory chips through a specific channel. In addition, the data storage device can include a plurality of physical channels for communication of data between the host and the plurality of memory chips, and the method can further include determining a number of the physical channels, where the determined channels are operably connected to memory chips of the first subset of memory chips and are operably connected to memory chips of the second subset of memory chips.
• The first subset may not include any memory chips of the second subset, and the second subset may not include any memory chips of the first subset. The method may further include receiving an indication that a memory chip of the first partition has failed or is likely to fail, re-defining, via the host coupled to the data storage device, the first partition of the data storage device to include a third subset of the plurality of memory chips, where the third subset is different from the first subset, and where the third subset does not include any memory chips of the second subset and where the second subset does not include any memory chips of the third subset. Re-defining the first partition can include defining the third subset as the first subset of memory chips but for the memory chip that has failed or that is approaching failure.
• In another general aspect, an apparatus includes a flash memory data storage device including a plurality of memory chips, and a host operably coupled to the data storage device via an interface. The host includes a configuration detection engine configured to detect a number of memory chips in the data storage device, a partition engine, and a driver. The partition engine configured to define a first partition of the data storage device, where the first partition includes a first subset of the plurality of memory chips and a second partition of the data storage device, where the second partition includes a second subset of the plurality of memory chips. The driver is configured to write first data to the first partition, read data from the second partition while the first data is being written to the first partition, and write the first data to the second partition while reading data from the first partition.
• Implementations can include one or more of the following features. For example, the driver can be further configured to write second data to the first partition while reading data from the second partition and to write the second data to the second partition while reading data from the first partition; and for N=3rd to at least 10th the driver can be further configured to write N data to the first partition, while reading data from the second partition to write the N data to the second partition while reading data from the first partition.
• The data storage device can be configured to transmit, upon receiving a command from the host, information from the data storage device to the host indicating the number of memory chips in the data storage device, and the transmitted information can include information about the physical architecture of the data storage device, including information about connections between particular memory chips and particular channels of the data storage device. The host can further include an address assignment engine configured to assign a memory address to data to be written to the data storage device, where the assigned memory address specifies that the data be written to a specific one of the plurality of memory chips.
• When the data storage device includes a plurality of physical channels for communication of data between the host and the plurality of memory chips, with each channel being operably connected to a different plurality of the memory chips, the configuration detection engine can be further configured to detect a number of the physical channels, and the partition engine can be further configured to determine a first subset of the number channels, where channels of the first subset of channels are operably connected only to memory chips of the first subset of memory chips and to determine a second subset of the number of channels, where channels of the second subset of channels are operably connected only to memory chips of the second subset of memory chips. The address assignment engine can be configured to assign a memory address to data to be written to the data storage device, where the assigned memory address specifies that the data be written to a specific one of the plurality of memory chips through a specific channel. In another implementation, when the data storage device includes a plurality of physical channels for communication of data between the host and the plurality of memory chips, the plurality of physical channels can be operably connected to memory chips of the first subset of memory chips and operably connected to memory chips of the second subset of memory chips.
• The partition engine is further configured to receive an indication that a memory chip of the first partition has failed o is likely to fail, to re-define the first partition of the data storage device to include a third subset of the plurality of memory chips, where the third subset is different from the first subset, and where the third subset does not include any memory chips of the second subset and where the second subset does not include any memory chips of the third subset.
• The details of one or more implementations are set forth in the accompanying drawings and the description below. Other features will be apparent from the description and drawings, and from the claims.
BRIEF DESCRIPTION OF THE DRAWINGS
• FIG. 1 is an exemplary block diagram of a data storage device.
• FIG. 2 is an exemplary perspective block diagram of the printed circuit boards of the data storage device.
• FIG. 3A is an exemplary block diagram of exemplary computing devices for use with the data storage device ofFIG. 1.
• FIG. 3B is an exemplary block diagram of exemplary computing devices for use with the data storage device ofFIG. 1.
• FIG. 4 is an exemplary flowchart illustrating an example process of storing data on the data storage device ofFIG. 1.
• FIG. 5 is an exemplary block diagram of an example implementation of the data storage device ofFIG. 1.
• FIG. 6 is an exemplary flowchart illustrating example operations of the data storage device ofFIG. 1.
DETAILED DESCRIPTION
• This document describes an apparatus, system(s) and techniques for data storage. Such a data storage apparatus may include a controller board having a controller that may be used with one or more different memory boards, with each of the memory boards having multiple flash memory chips. The data storage apparatus may communicate with a host using an interface on the controller board. In this manner, the controller on the controller board may be configured to receive commands from the host using the interface and to execute those commands using the flash memory chips on the memory boards.
• FIG. 1 is a block diagram of adata storage device100. Thedata storage device100 may include acontroller board102 and one ormore memory boards104aand104b.Thedata storage device100 may communicate with ahost106 over aninterface108. Theinterface108 may be between thehost106 and thecontroller board102. Thecontroller board102 may include acontroller110,DRAM111, multiplephysical channels112, apower module114, and amemory module116. Thememory boards104aand104bmay include multipleflash memory chips118aand118bon each of the memory boards. Thememory boards104aand104balso may include amemory device120aand120b.
• In general, thedata storage device100 may be configured to store data on theflash memory chips118aand118b.Thehost106 may write data to and read data from theflash memory chips118aand118b,as well as cause other operations to be performed with respect to theflash memory chips118aand118b.The reading and writing of data between thehost106 and theflash memory chips118aand118b,as well as the other operations, may be processed through and controlled by thecontroller110 on thecontroller board102. Thecontroller110 may receive commands from thehost106 and cause those commands to be executed using theflash memory chips118aand118bon thememory boards104aand104b.The communication between thehost106 and thecontroller110 may be through theinterface108. Thecontroller110 may communicate with theflash memory chips118aand118busing thechannels112.
• Thecontroller board102 may includeDRAM111. TheDRAM111 may be operably coupled to thecontroller110 and may be used to store information. For example, theDRAM111 may be used to store logical address to physical address maps and bad block information. TheDRAM111 also may be configured to function as a buffer between thehost106 and theflash memory chips118aand118b.In one exemplary implementation, thecontroller board102 and each of thememory boards104aand104bare physically separate printed circuit boards (PCBs). Thememory board104amay be on one PCB that is operably connected to thecontroller board102 PCB. For example, thememory board104amay be physically and/or electrically connected to thecontroller board102. Similarly, thememory board104bmay be a separate PCB from thememory board104aand may be operably connected to thecontroller board102 PCB. For example, thememory board104bmay be physically and/or electrically connected to thecontroller board102.
• Thememory boards104aand104beach may be separately disconnected and removable from thecontroller board102. For example, thememory board104amay be disconnected from thecontroller board102 and replaced with another memory board (not shown), where the other memory board is operably connected tocontroller board102. In this example, either or both of thememory boards104aand104bmay be swapped out with other memory boards such that the other memory boards may operate with thesame controller board102 andcontroller110. For example, thememory board104bmay be physically and/or electrically connected to thecontroller board102.
• In one exemplary implementation, thecontroller board102 and each of thememory boards104aand104bmay be physically connected in a disk drive form factor. The disk drive form factor may include different sizes such as, for example, a 3.5″ disk drive form factor and a 2.5″ disk drive form factor.
• In one exemplary implementation, thecontroller board102 and each of thememory boards104aand104bmay be electrically connected using a high density ball grid array (BGA) connector. Other variants of BGA connectors may be used including, for example, a fine ball grid array (FBGA) connector, an ultra fine ball grid array (UBGA) connector and a micro ball grid array (MBGA) connector. Other types of electrical connection means also may be used.
• Theinterface108 may include a high speed interface between thecontroller110 and thehost106. The high speed interface may enable fast transfers of data between thehost106 and theflash memory chips118aand118b.In one exemplary implementation, the high speed interface may include a Peripheral Component Interconnect Express (“PCIe”) interface. For instance, the PCIe interface may be a PCIe x4 interface or a PCIe x8 interface. Theinterface108 may include a connector to thehost106 such as, for example, an external PCIe connector cable assembly. Other high speed interfaces, connectors and connector assemblies also may be used.
• In one exemplary implementation, the communication between thecontroller board102 and theflash memory chips118aand118bon thememory boards104aand104bmay be arranged and configured into multiplephysical channels112. Each of thechannels112 may communicate with one or moreflash memory chips118aand118b.Thecontroller110 may be configured such that commands received from thehost106 may be executed by thecontroller110 using each of thechannels112 simultaneously or at least substantially simultaneously. In this manner, multiple commands may be executed simultaneously on differentphysical channels112, which may improve throughput of thedata storage device100.
• In the example ofFIG. 1, twenty (20)physical channels112 are illustrated. The completely solid lines illustrate the ten (10) physical channels between thecontroller110 and theflash memory chips118aon thememory board104a.The mixed solid and dashed lines illustrate the ten (10) channels between thecontroller110 and theflash memory chips118bon thememory board104b.As illustrated inFIG. 1, each of thechannels112 may support multiple flash memory chips. For instance, each of thechannels112 may support up to 32 flash memory chips. In one exemplary implementation, each of the 20 channels may be configured to support and communicate with 6 flash memory chips. In this example, each of thememory boards104aand104bwould include 60 flash memory chips each. Depending on the type and the number of theflash memory chips118aand118b,thedata storage100 device may be configured to store up to and including multiple terabytes of data.
• Thecontroller110 may include a microcontroller, a FPGA controller, other types of controllers, or combinations of these controllers. In one exemplary implementation, thecontroller110 is a microcontroller. The microcontroller may be implemented in hardware, software, or a combination of hardware and software. For example, the microcontroller may be loaded with a computer program product from memory (e.g., memory module116) including instructions that, when executed, may cause the microcontroller to perform in a certain manner. The microcontroller may be configured to receive commands from thehost106 using theinterface108 and to execute the commands. For instance, the commands may include commands to read, write, copy and erase blocks of data using theflash memory chips118aand118b,as well as other commands.
• In another exemplary implementation, thecontroller110 is a FPGA controller. The FPGA controller may be implemented in hardware, software, or a combination of hardware and software. For example, the FPGA controller may be loaded with firmware from memory (e.g., memory module116) including instructions that, when executed, may cause the FPGA controller to perform in a certain manner. The FPGA controller may be configured to receive commands from thehost106 using theinterface108 and to execute the commands. For instance, the commands may include commands to read, write, copy and erase blocks of data using theflash memory chips118aand118b,as well as other commands.
• Thememory module116 may be configured to store data, which may be loaded to thecontroller110. For instance, thememory module116 may be configured to store one or more images for the FPGA controller, where the images include firmware for use by the FPGA controller. Thememory module116 may interface with thehost106 to communicate with thehost106. Thememory module116 may interface directly with thehost106 and/or may interface indirectly with thehost106 through thecontroller110. For example, thehost106 may communicate one or more images of firmware to thememory module116 for storage. In one exemplary implementation, thememory module116 includes an electrically erasable programmable read-only memory (EEPROM). Thememory module116 also may include other types of memory modules.
• Thememory boards104aand104bmay be configured to operate with different types offlash memory chips118aand118b.In one exemplary implementation, theflash memory chips118aand theflash memory chips118bmay be the same type of flash memory chips including requiring the same voltage from thepower module114 and being from the same flash memory chip vendor. The terms vendor and manufacturer are used interchangeably throughout this document.
• In another exemplary implementation, theflash memory chips118aon thememory board104amay be a different type of flash memory chip from theflash memory chips118bon thememory board104b.For example, thememory board104amay include SLC NAND flash memory chips and thememory board104bmay include MLC NAND flash memory chips. In another example, thememory board104amay include flash memory chips from one flash memory chip manufacturer and thememory board104bmay include flash memory chips from a different flash memory chip manufacturer. The flexibility to have all the same type of flash memory chips or to have different types of flash memory chips enables thedata storage device100 to be tailored to different applications being used by thehost106.
• In another exemplary implementation, thememory boards104aand104bmay include different types of flash memory chips on the same memory board. For example, thememory board104amay include both SLC NAND chips and MLC NAND chips on the same PCB. Similarly, thememory board104bmay include both SLC NAND chips and MLC NAND chips. In this manner, thedata storage device100 may be advantageously tailored to meet the specifications of thehost106.
• In another exemplary implementation, thememory board104aand104bmay include other types of memory devices, including non-flash memory chips. For instance, thememory boards104aand104bmay include random access memory (RAM) such as, for instance, dynamic RAM (DRAM) and static RAM (SRAM) as well as other types of RAM and other types of memory devices. In one exemplary implementation, the both of thememory boards104aand104 may include RAM. In another exemplary implementation, one of the memory boards may include RAM and the other memory board may include flash memory chips. Also, one of the memory boards may include both RAM and flash memory chips.
• Thememory modules120aand120bon thememory boards104aand104bmay be used to store information related to theflash memory chips118aand118b,respectively. In one exemplary implementation, thememory modules120aand120bmay store device characteristics of the flash memory chips. The device characteristics may include whether the chips are SLC chips or MLC chips, whether the chips are NAND or NOR chips, a number of chip selects, a number of blocks, a number of pages per block, a number of bytes per page and a speed of the chips.
• In one exemplary implementation, thememory modules120aand120bmay include serial EEPROMs. The EEPROMs may store the device characteristics. The device characteristics may be compiled once for any given type of flash memory chip and the appropriate EEPROM image may be generated with the device characteristics. When thememory boards104aand104bare operably connected to thecontroller board102, then the device characteristics may be read from the EEPROMs such that thecontroller110 may automatically recognize the types offlash memory chips118aand118bthat thecontroller110 is controlling. Additionally, the device characteristics may be used to configure thecontroller110 to the appropriate parameters for the specific type or types offlash memory chips118aand118b.
• As discussed above, thecontroller110 may include a FPGA controller. Referring toFIG. 2, an exemplary block diagram of aFPGA controller210 is illustrated. The FPGA controller may be configured to operate in the manner described above with respect tocontroller110 ofFIG. 1. TheFPGA controller210 may includemultiple channel controllers250 to connect the multiplephysical channels112 to theflash memory chips218. Theflash memory chips218 are illustrated as multiple flash memory chips that connect to each of thechannel controllers250. Theflash memory chips218 are representative of theflash memory chips118aand118bofFIG. 1, which are on theseparate memory boards104aand104bofFIG. 1. The separate memory boards are not shown in the example ofFIG. 2. TheFPGA controller210 may include aPCIe interface module208, a bi-directional direct memory access (DMA)controller252, a dynamic random access memory (DRAM)controller254, a command processor/queue256 and an Information andconfiguration interface module258.
• Information may be communicated with a host (e.g., host106 ofFIG. 1) using an interface. In this example,FIG. 2, theFPGA controller210 includes a PCIe interface to communicate with the host and aPCIe interface module208. ThePCIe interface module208 may be arranged and configured to receive commands from the host and to send commands to the host. ThePCIe interface module208 may provide data flow control between the host and the data storage device. ThePCIe interface module208 may enable high speed transfers of data between the host and thecontroller210 and ultimately theflash memory chips218. In one exemplary implementation, the PCIe interface and thePCIe interface module208 may include a 64-bit bus. The bi-directional direct memoryaccess DMA controller252 may be arranged and configured to control the operation of the bus between thePCIe interface module208 and the command processor/queue256. Thebi-directional DMA controller252 may be configured to interface with thePCIe interface208, and each of thechannel controllers250. Thebi-directional DMA controller252 enables bi-directional direct memory access between thehost106 and theflash memory chips218.
• TheDRAM controller254 may be arranged and configured to control the translation of logical to physical addresses. For example, in an implementation in which the host addresses the memory space using logical addresses, theDRAM controller254 may assist the command processor/queue256 with the translation of the logical addresses used by the host to the actual physical addresses in theflash memory chips218 related to data being written to or read from theflash memory chips218. A logical address received from the host may be translated to a physical address for a location in one of theflash memory chips218. Similarly, a physical address for a location in one of theflash memory chips218 may be translated to a logical address and communicated to the host.
• The command processor/queue256 may be arranged and configured to receive the commands from the host through thePCIe interface module208 and to control the execution of the commands through thechannel controllers250. The command processor/queue256 may maintain a queue for a number of commands to be executed and order the commands using an ordered list to ensure that the oldest commands may be processed first. Thecommand processor100 may maintain the order of the commands designated for the same flash memory chip and may reorder the commands designated for different flash memory chips. In this manner, multiple commands may be executed simultaneously and each of thechannels112 may be used simultaneously or at least substantially simultaneously.
• The command processor/queue256 may be configured to process commands fordifferent channels112 out of order and preserve per-channel command ordering. For instance, commands that are received from the host and that are designated for different channels may be processed out of order by the command processor/queue256. In this manner, the channels may be kept busy. Commands that are received from the host for processing on the same channel may be processed in the order that the commands were received from the host by the command processor/queue256. In one exemplary implementation, the command processor/queue256 may be configured to maintain a list of commands received from the host in an oldest-first sorted list to ensure timely execution of the commands.
• Thechannel controllers250 may be arranged and configured to process commands from the command processor/queue256. Each of thechannel controllers250 may be configured to process commands for multipleflash memory chips218. In one exemplary implementation, each of thechannel controllers250 may be configured to process commands for up to and including32flash memory chips218.
• Thechannel controllers250 may be configured to process the commands from the command processor/queue256 in order as designated by the command processor/queue256. Examples of the commands that may be processed include, but are not limited to, reading a flash page, programming a flash page, copying a flash page, erasing a flash block, reading a flash block's metadata, mapping a flash memory chip's bad blocks, and resetting a flash memory chip.
• The information andconfiguration interface module258 may be arranged and configured to interface with a memory module (e.g.,memory module116 ofFIG. 1) to receive configuration information for theFPGA controller210. For example, the information andconfiguration interface module258 may receive one or more images from the memory module to provide firmware to theFPGA controller210. Modifications to the images and to the firmware may be provided by the host to thecontroller210 through the information andconfiguration interface module258. Modifications received through the information andconfiguration interface module258 may be applied to any of the components of thecontroller210 including, for example, thePCIe interface module208, the bi-directional direct memoryaccess DMA controller252, theDRAM controller254, the command processor/queue256 and thechannel controllers250. The information andconfiguration interface module258 may include one or more registers, which may be modified as necessary by instructions from the host.
• TheFPGA controller210 may be arranged and configured to cooperate and process commands in conjunction with the host. TheFPGA controller210 may perform or at least assist in performing error correction, bad block management, logical to physical mapping, garbage collection, wear levelling, partitioning and low level formatting related to theflash memory chips218.
• FIG. 3A is a schematic block diagram of an apparatus300 including adata storage device302 having a plurality offlash memory chips318a,318b,318c,318d,318e,318f,318g,318h,318i,318j,318k,3181 that are organized into afirst partition321 and asecond partition322. The first andsecond partition321 and322 define different physical areas of storage space in thedata storage device302, such that directories and files of different categories can be stored in the different partitions, or so that one partition can be used for different purposes than the other partition. The first partition can include a first subset of the flash memory chips318a-f,while the second partition can include a second subset of theflash memory chips318g-l,where there are not any flash memory chips that are part of both partitions. That is, the boundary between thepartitions321 and322 is drawn between individual flash memory chips to ensure that an individual flash memory chip does not belong to more than one partition.
• Organizing the data storage device into two or more partitions can serve a number of purposes. For example, operating system files stored on one partition can be kept separate from user files stored on another partition. Cache and log files that can change size dynamically and rapidly, potentially making a file system full, can be stored on one partition and kept separate from other files stored on a different partition. Partitions can be used for multi-booting setups, which allow users to have more than one operating system on a single computer. For example, a user could install Linux, Mac OS X, and Microsoft Windows, or other operating systems on different partitions of the same data storage device and have a choice of booting into any operating system (supported by the hardware) at power-up. Partitions can be used to protect or isolate files to make it easier to recover a corrupted file system or operating system installation. For example, if one partition is corrupted but none of the other file systems are affected, the data on the storage device may still be salvageable. Using a separate partition for read-only data also reduces the chances of the file system on that partition becoming corrupted. Partitions also can raise overall computer performance on systems where smaller file systems are more efficient. For example, large hard drives with only one NTFS file system typically have a very large sequentially-accessed Master File Table (MFT), and it generally takes more time to read this MFT than the smaller MFTs of smaller partitions.
• In another example embodiment, thedata storage device302 may be used to store large amounts of data (e.g., many Gigabytes or Terabytes of data) that must be read quickly from the data storage device and supplied to the host. For example, the data storage device can be used to cache large volumes of publicly accessible information (e.g., a large corpus of web pages from the World Wide Web, a large library of electronic versions of books, or digital information representing a large volume of telecommunications, etc.) that can be fetched by the host in response to a query. Thus, it can be important that the relevant data be accessed and returned very quickly in response to a read command issued by the host. However, the information stored in the data storage device also may need to be constantly updated to keep the information up to date as the relevant information changes. For example, if the information on the storage device relates to a corpus of web pages, the information stored on the storage device may need to be updated as the web pages change and as new web pages are created.
• In such a system, a partitioned flash memorydata storage device302 can offer exceptional performance. In a flash memory storage device, write operations to a flash memory chip take much longer (e.g., 10-100 times longer) than read operations from a flash memory chip. In various embodiments, each flash memory chip318a-318lmay communicate withhost350 over a single communication channel312a-321fper individual storage medium, such that, either a single read or write (but not both) on a given flash memory chip within a given time frame. In such an embodiment, a write command to a storage medium may block a potential read operation from the same device.
• For example, with flash memory chips318a-318l,the time or latency needed to complete a write command may be much greater than the time or latency needed to read from complete a read command. In addition, flash memory chips318a-318lmay incur multiple transactions in order to complete a single write operation. An example of this may include “garbage collection.”
• Therefore, organizing the chips318a-lof the data storage device into two or more partitions, where the partitions are defined at boundaries between different chips, offers a way to ensure fast read operations while also allowing the information stored on the data storage device to be updated in real time. For example, bothpartitions321 and322 can be used to store substantially the same corpus of data (e.g., a corpus of web pages) to be served in response to queries, and the individual partitions can alternate between serving the requests and being updated with new information. For instance, in a first time period thefirst partition321 can be used to provide the information to the host (e.g., information that may be requested in response to a user query), while the data on thesecond partition322 is updated (e.g., in response to changes or additions to the web pages of the corpus). Then, in a second time period, the recently updatedsecond partition322 can be used to provide the information to the host, while the data on thefirst partition321 is updated. In this manner, the data on the first partition can be mirrored on the second partition, so that the second partition can maintain data that is substantially identical to the data on the first partition. To ensure that the two partitions maintain substantially the same corpus of data and that the second partition mirrors the first partition by storing substantially the same data as the first partition, the host can write data to the first portion, and then the host can write the same data that was written to the first partition to the second partition. The host may perform additional operations to ensure that the second partition mirrors the first partition. For example, if the host receives an indication from thedevice302 that the a flash memory chip on either of the partitions has failed or is likely to fail, the host may copy data corresponding to the data on the failed or soon-to-fail chip onto another chip of the partition. In one implementation, the host may copy the data from the partition that does not include the failed or soon-to-fail.
• By preparing mirroredpartitions321 and322 on thedevice302, data can always be served from a partition that acts as a read-only device, and therefore provides very fast responses to read commands from the host without being slowed down by write commands, while the other partition is being updated with new information. Defining the partitions such that an individual flash memory chip is included in only one partition ensures that no flash chip will have data written to it and read from it at substantially the same time, which would cause a delay in responding to a read request from thehost350. However, in another implementation, boundaries between the two mirrored partitions need not be drawn along physical chip boundaries, in which case some physical memory addresses of a chip may belong to one partition and other physical memory addresses of the chip may belong to the other mirrored partition.
• As discussed above, the memory chips318a-lcan be connected to a controller that may include aFPGA controller310. The FPGA controller may be configured to operate in the manner described above with respect tocontroller110 ofFIG. 1 or ofFPGA210 ofFIG. 2. TheFPGA controller310 may includemultiple channel controllers312a,312b,312c,312d,312e,312fto connect themultiple channels112 to the flash memory chips318a-l.Of course, as described above, the storage device can include many more than 12 flash memory chips, many more than six channel controllers, and many more than two flash memory chips may be operably connected to a channel controller across a physical channel. Thus, the implementation shown inFIGS. 3A and 3B is merely schematic for clarity of illustration.
• In one implementation,channel controllers312a,312b,312c,312d,312e,312fcan control channels that are operably connected to flash memory chips that are part of eachpartition321 and322. For example,channel controller312acan be operably connected tomemory chip318a,which is part of thefirst partition321, and also tomemory chip318g,which is part of thesecond partition322. In such a configuration, at least one memory chip in thefirst partition321 is connected to each communication channel between thedata storage device302 and the host, and at least one memory chip in thesecond partition322 is connected to each communication channel between thedata storage device302 and thehost350. Such a configuration results in maximum parallelism of communication between apartition321 or322 and the host, which can result in fast read access and fast write times from and to thedata storage device302.
• In another implementation, approximately half the channel controllers can be operably connected to flash memory chips in a first partition and approximately half the channel controllers can be operably connected to flash memory chips in the second partition.
• In another implementation, shown inFIG. 3B,flash memory chips318a,318b,318c,318d,318e,318f,318g,318h,318i,318j,318k,318lcan be organized into afirst partition331, asecond partition322, athird partition333, and afourth partition334, where the different partitions define different physical areas of storage space in thedata storage device302, such that directories and files of different categories can be stored in the different partitions, or so that one partition can be used for different purposes than the other partition. Thefirst partition331 can include a first subset of the flash memory chips318a-c.Thesecond partition332 can include a second subset of theflash memory chips318d-f.Thethird partition333 can include a third subset of theflash memory chips318g-i.Thefourth partition334 can include a fourth subset of theflash memory chips318j-l.In one implementation, among thedifferent partitions331,332,333, and334 there are not any flash memory chips whose physical memory address space is part of two or more partitions. That is, the boundaries between thepartitions331,332,333, and334 are drawn between individual flash memory chips to ensure that an individual flash memory chip does not belong to more than one partition.
• In the system ofFIG. 3B, a partitioned flash memorydata storage device302 can offer exceptional performance, e.g., when used to store a corpus of data (e.g., a corpus of web pages) to be served in response to queries and the individual partitions can alternate between serving the requests and being updated with new information. For instance, in a first time period the first, second andthird partitions331,332, and333 can be used to provide the information to the host (e.g., information that may be requested in response to a user query), while the data on thefourth partition334 is updated (e.g., in response to changes or additions to the web pages of the corpus). Then, in a second time period, the recently updatedfourth partition334, along with the second andthird partitions332 and332 can be used to provide the information to the host, while the data on thefirst partition331 is updated. Thus, data on each partition can be updated in round robin fashion, while query requests are served by the other partitions. This process can be repeated so that data is always served from partitions that act as read-only devices, and therefore provides very fast responses to read commands from the host without being slowed down by write commands, while the other partition is being updated with new information. Defining four partitions results in redundancy of information stored on the data storage device, so that if a partition, channel, or individual memory chip fails, such that one partition is no longer usable, the remaining three partitions can continue to be used to provide a data storage device in which each of the remaining partitions takes turns being updated while the other remaining partitions serve data requests.
• As described above, thedata storage device302 can be connected to ahost350 though aninterface308, which can be a high speed interface, such as, for example a PCIe interface. The host can include, for example, aprocessor352, afirst memory354, asecond memory356, a memorydevice detection engine358, and apartition engine360. Thefirst memory354 can include, for example, a non-volatile memory device (e.g., a hard disk) adapted for storing machine-readable, executable code instructions that can be executed by theprocessor352. The code instructions stored on thefirst memory354 can loaded into the second memory (e.g., a volatile memory, such as, a random access memory)356 where they can be executed by theprocessor352 to create the memorydevice detection engine358 and thepartition engine360. The second memory can include logical blocks of “user space”363 devoted to user mode applications and logical blocks of “kernel space”364 devoted to running the lower-level the resources that user-level applications must control to perform their functions. The memorydevice detection engine358 and thepartition engine360 can reside in thekernel space364 of thesecond memory356.
• The memorydevice detection engine358 can be configured to detect the number of flash memory chips318 on thedata storage device302, and thepartition engine360 can be configured to define thefirst partition321 and thesecond partition322 of the data storage device. Thus, the memorydevice detection engine358 and thepartition engine360, which run on thehost350, can be used by the host to discover hardware device properties of thedata storage device302 and then to define, via the host, thepartitions321 and322. In one implementation, the memorydevice detection engine358 can issue a query command to the data storage device, and in response to the query command the data storage device can return information to the host about, for example, the number of flash memory chips318, the size (e.g., as measured in bytes) of each chip, the number of channels in the data storage device, the flash memory chips to which each the channel controller312a-eis operably connected. Such information can be stored on theEEPROM116 on thecontroller board310 and/or on theEEPROM120aof the flash board of thedata storage device302. The memory device detection engine can poll theEEPROM116 or theEEPROM120a(e.g., during a boot-up operation of the host350) to cause the data storage device to return such information to thehost350. In another implementation, the host may poll the flash memory chips318 to provide the information about, for example, the number of flash memory chips318, the size (e.g., as measured in bytes) of each chip, the number of channels in the data storage device, the flash memory chips to which each the channel controller312a-eis operably connected.
• Thepartition engine360 can receive the information from the memorydevice detection engine358 about the number of flash chips318, the size of each flash chip, the number of channels and the memory chips to which each channels is operably connected, and, based on this information, the partition engine can define afirst partition321 andsecond partition322 in thedata storage device302. For example, each partition size can be allocated in memory block units, which are standard units of the erase operation in flash memory. The partition engine running on thehost350 can define the first partition to include memory blocks drawn from a first subset of the memory chips318 and the second partition memory blocks drawn from a second subset of the memory chips318, where the first subset does not include any flash chips of the second subset and the second subset does not include any flash chips of the first subset. Thepartition engine360 then can map the physical memory block addresses (which may include, for example, a unique channel number, a unique flash memory chip number, and a block address within the flash memory chip) to logical addresses that can be used by application programs running the in the user space, such that the user space applications running on thehost350 can read data from thedata storage device302 and write data to thedata storage device302 with reference to the logical space addresses.
• After a partition scheme of multiple partitions has been defined and data has been stored on the flash memory chips of thedata storage device100, the device can store information about the partitioning scheme, e.g., on thememory116, so that the when the device is booted at a later time, it can communicate the partitioning scheme to thehost106 for the host to use. For example, the device may maintain information about the physical configuration of the data storage device, including a number of flash memory chips in the device and about the partitioning scheme, including which flash memory storage chips and channels are associated with which partitions on thememory116. Then, when the system including thehost106 and thedata storage device100 is booted, thestorage device100 can communicate this information to thehost106, e.g., in response to a read operation performed by theconfiguration detection engine358 of thehost106. Thepartitioning engine360 of thehost106 then can define the partitions for the operating system and applications running on the host. For example, thepartitioning engine360 can define a first and second partition based on the information read from thestorage device100, where the first and second partitions do not include any of the same memory chips. Thepartitioning engine360 also can allocate a logical to physical memory map for the first and second partitions, so that the user-level application programs running on the host can use logical addresses that then are mapped (e.g., theaddress assignment engine366 running inkernel space364 of the host) to physical memory addresses of the flash memory chips of thestorage device100.
• Thepartition engine360 also can be used to re-define the first partition of the data storage device to include a third subset of the plurality of flash memory chips, where the third subset is different from the first subset, and where the third subset does not include any flash memory chips of the second subset and wherein the second subset does not include any flash memory chips of the third subset. For example, with reference toFIG. 3A andFIG. 3B, a user may decide that the original partition scheme shown inFIG. 3A does not suit his or her needs, and therefore may use the host to redefine thepartitions321 and322 (e.g., to include more or fewer flash memory chips in the particular partitions) or to add additional partitions to the scheme. In one implementation, thefirst partition321 can be redefined aspartitions331 and333. Allowing the user to define the partitions through the host rather that forcing the user to accept a partition scheme that is pre-defined by, or pre-loaded in, thecontroller310 gives the user flexibility to define partitions as he or she desires and to change the partition scheme when the need arises. In another implementation, the imminent failure of one of the flash memory chips, e.g.,318a,may be detected by the host, and in response to this information, the partition engine may re-define thefirst partition321 to exclude theflash memory chip318afrom the partition, i.e., as the originally defined first partition but for thememory chip318a.Thus, any number of partitions can be defined (up to the number offlash memory chips118aand118bin the storage device100), and different partitions within a partition scheme can include different numbers of flash memory chips and can include different amounts of memory space.
• The host also may include anaddress assignment engine366 that can exist in thekernel364 and that can assign physical memory addresses to data to be written to thedata storage device302. For example, an application running inuser space363 may call for data to be written from thehost350 to thedata storage device302, and the user space application may specify that the data be written to a particular logical memory address. Theaddress assignment engine366 may translate the logical address into a physical address that can include for example, a particular channel that the data should be written to, a particular flash memory chip operably connected to the specified channel to which the data should be written, and a particular physical block address of the specified memory chip to which the data should be written. In such an implementation, the translation of logical addresses to physical memory space addresses can be performed by theaddress assignment engine366, such that role of theDRAM controller254 of theFPGA210 is reduced or irrelevant.
• Once the partitions have been defined, data can be written to thedata storage device310 in a manner that mirrors the data of one partition on another partition. For example, thehost350 may include adevice driver362 operating inkernel space364 of thememory356, which can be used to communicate data to and from thedata storage device310. To mirror data between two partitions, thedevice driver362 can write first data from thehost350 first data to afirst partition321 and can read data asecond partition322 while the first data is being written to the first partition. Then thedriver362 can write the first data to thesecond partition322 while reading data from thefirst partition321. The driver can continue mirroring data between the two partitions by writing data alternately between the first andsecond partitions321 and322. For example, thedriver362 can perform a loop for N pieces of data, in which the driver writes the N^thdata to the first partition, reads data from the second partition while the N^thdata is being written to the first partition, and writes the N^thdata to the second partition while reading data from the first partition.
• FIG. 4 is an exemplary flowchart illustrating anexample process400 of partitioning the data storage device ofFIG. 1, where the device includes a plurality of flash memory chips.Process400 can include determining a number of flash memory chips in the data storage device (402). For example, the configuration detection engine can query the data storage device to gather information about the number of flash memory chips in the data storage device. A first partition of the data storage device can be defined, via a host coupled to the data storage device, where the first partition includes a first subset of the plurality of flash memory chips (404). A second partition of the data storage device can be defined, via the host, where the second partition includes a second subset of the plurality of flash memory chips (406). First data is written to the first partition while reading data from the second partition (407), and the first data is written to the second partition while reading data from the second partition (409).
• Particular implementations can include certain optional features. For example, determining the number flash memory chips in the data storage device can include transmitting information from the data storage device to the host indicating the number of flash memory chips in the data storage device (410). An address location in the data storage device to which to write data from the host can be defined in the host, where the address location specifies that the data be written to a specific one of the plurality of memory chips (412).
• When the data storage device includes a plurality of physical channels for communication of data between the host and the plurality of flash memory chips, with each channel being operably connected to a different plurality of the memory chips, theprocess400 can further include determining the number of physical channels (414), determining a first subset of the channels, where channels of the first subset of the channels are operably connected only to memory chips of the first subset of memory chips (416), determining a second subset of the channels, where channels of the second subset of the channels are operably connected only to memory chips of the second subset of memory chips (418), and defining, in the host, an address location in the data storage device to which to write data from the host, wherein the address location specifies that the data be written to a specific one of the plurality of memory chips through a specific channel (420). In addition, theprocess400 can include re-defining, via the host coupled to the data storage device, the first partition of the data storage device to include a third subset of the plurality of flash memory chips (422). In such an implementation, when the first subset of channels is connected only to memory chips of the first partition and when the second subset of channels is connected only to memory chips of the second partition, then the host always has channels with which to access each partition. In another implementation, all of the channels can be connected to memory chips of the first partition and of the second partition (424), and in such an implementation, when all of the channels are used to communicate with each partition then each partition may take advantage of using all the channels to communicate with the host at the expense of the other partition not having any channels with which to communicate with the host.
• FIG. 5 is an exemplary block diagram of an example implementation of an apparatus500 in which ahost551 can control the striping of data acrossdifferent channels513,523,533,543 toflash memory chips514,515,516,517,524,525,526,527,534,535,536,537,544,545,546, and547 of adata storage device501 and/or across the different flash memory chips. For example, logically sequential data (e.g., data of a file) can be broken up into segments and the segments can be assigned todifferent channels513,523,533,543 or to differentflash memory chips514,515,516,517,524,525,526,527,534,535,536,537,544,545,546, and547. By segmenting the data and striping it across different channels and/or flash memory chips, e.g., in a round-robin fashion, different segments of the logically sequential data can be written to different physical devices (e.g., channels or flash memory chips) concurrently. Because the time required to write data to a flash memory chip is non-trivial compared to the time for aprocessor552 of thehost551 to process data packets destined for thestorage device501, striping the data acrossdifferent channels513,523,533,543 or to differentflash memory chips514,515,516,517,524,525,526,527,534,535,536,537,544,545,546, and547 can speed the writing of the logically sequential data from thehost551 to thestorage device501. Similarly, reading striped logically sequential data back from thestorage device501, where the data has been striped across different channels or chips, can be faster that reading the data across a single channel or from a single chip. Thus, when reading back striped data, a first segment of logically sequential data can be read back to the host551 (e.g., from a chip514) across afirst channel513, while the next segment of the logically sequential data is being fetched from another chip (e.g., chip524) for transmission across asecond channel514.
• When striping logically sequential data to particularflash memory chips514,515,516,517,524,525,526,527,534,535,536,537,544,545,546, and547 using “chip striping” the host can specify the destination memory address for a particular segment, where the specified address can include a particular flash memory chip to which the segment is to be written. Thus, the striping of data to particular chips can be placed under the control of thehost551. This can provide a great degree of parallelism when writing data to and reading data from thestorage device501. For example, an in implementation of the storage device that includes 12 channels and 20 flash memory chips per channel, a file can be striped across all 240 flash memory chips, which means that 240 write or read operations can be performed when accessing the chips in a round-robin fashion before a chip needs to be accessed a second time. This high degree of parallelism results can result in a high data throughput rate between thehost551 and thestorage device501, such that data can be read from and written to the storage device very quickly.
• When striping logically sequential data acrossparticular channels513,523,533,543 using “channel striping” the host can specify the destination memory address for a particular segment, where the specified address can include a particular channel to which the segment is to be written. Then, at the time the segment is written to the specified channel the particular flash memory chip operably connected to the specified channel to which the segment is written can be chosen dynamically by thehost551 based on the current run-time state of the chips, e.g., base on chip space availability of the different chips. Channel striping can be more impervious to chip failures than chip striping, because if a single chip fails when using channel striping, the storage device can continue to operate. In addition, channel striping offers advantages over chip striping in terms of write performance, as opposed to read performance, because the optimum chip of all chips operably connected to a specified channel is selected dynamically for writing date. Because of the write performance advantages of channel striping, garbage collection, which involves several write operations, can be performed efficiently when using channel striping.
• Thus, the striping of data to particular chips can be placed under the control of thehost551. This can provide a great degree of parallelism when writing data to and reading data from thestorage device501. For example, an in implementation of the storage device that includes 40 channels and 16 flash memory chips per channel, a file can be striped across all 640 flash memory chips, which means that 640 write or read operations can be performed when accessing the chips in a round-robin fashion before a chip needs to be accessed a second time. This high degree of parallelism results can result in a high data throughput rate between thehost551 and thestorage device501, such that data can be read from and written to the storage device very quickly.
• Similar to the embodiment discussed above in connection withFIG. 3, theflash memory chips514,515,516,517,524,525,526,527,534,535,536,537,544,545,546, and547 can be connected to a controller that may include aFPGA controller510. TheFPGA controller510 may be configured to operate in the manner described above with respect tocontroller110 ofFIG. 1, theFPGA210 ofFIG. 2, or theFPGA310 ofFIG. 3. TheFPGA controller510 may includemultiple channel controllers512,522,532,542 that are operably connected via respectivephysical channels513,523,533,543 to respective groups of flash memory chips:514,515,516, and517;524,525,526, and527;534,535,536, and537; and544,545,546, and547. Of course, as described above, the storage device can include many more than 16 flash memory chips, many more than four channel controllers, and many more than four flash memory chips may be operably connected to a channel controller across a physical channel. Thus, the implementation shown inFIG. 5 is merely schematic for clarity of illustration.
• As described above, thedata storage device501 can be connected to ahost551 though aninterface508, which can be a high speed interface, such as, for example a PCIe interface. The host can include, for example, aprocessor552, afirst memory554, and asecond memory560. Thesecond memory560 can include, for example, volatile memory (e.g., random access memory) into which executable instructions are loaded for fast execution by theprocessor552. The first memory454 can include, for example, a non-volatile memory device (e.g., a hard disk) adapted for storing machine-readable, executable code instructions that can be executed by theprocessor552. The code instructions stored on thefirst memory554 can loaded into the second memory (e.g., a volatile memory, such as, a random access memory)560 where they can be executed by theprocessor552 to stripe data using “chip striping,” “channel striping” or a combination of both. The second memory can include logical blocks of “user space”562 devoted to user mode applications and logical blocks of “kernel space”564 devoted to running the lower-level the resources that user-level applications must control to perform their functions. Within thekernel space564 of thesecond memory560 can reside aninitialization engine566 for setting up a striping scheme, asegmentation engine568 for segmenting logically sequential data into segments, astriping engine570 for striping the data across distinct physical elements (e.g., channels or chips) of thestorage device501, and anaddress assignment engine572 for assigning addresses to the data segments.
• Aninitialization engine566 can be configured to determine a first channel chunk size with which to write data to flash memory chips connected to separate channels. In one implementation, the initialization engine can determine the first channel chunk size based on information about the page size of data that is written to the flash memory chips in thestorage device501 and based on information about the number of flash memory chips that are connected to channels in thestorage device501. For example, if the storage device includes 40 channels and 16 flash memory chips are connected to each channel, and the page size is 4K, then the initialization engine may determine an appropriate channel chunk size to be some multiple of 4K (e.g., 8K, 32K, 40K, or 80K). Theinitialization engine566 can receive this information about the physical configuration of thestorage device501 from a storage medium (e.g., an EEPROM)520 that stores information about, for example, the number ofphysical channels513,523,533,543 in thedevice501, the number offlash memory chips514,515,516,517,524,525,526,527,534,535,536,537,544,545,546, and547 in the device, the type of flash memory chips (e.g., single-level cell (“SLC”) flash or multilevel cell (“MLC”) flash) in the storage device, and the page size of data written to the chips. The host550 can transmit a command to thestorage device501 to request the transfer of such information about the physical parameters of the storage device (e.g., the number of channels, number of chips, type of chips, and page size), and in response to the command thestorage device501 can transmit the information back to the host550.
• When logically sequential data is written to thestorage device501 using a channel striping technique, the logically sequential data can be segmented in channel chunk size units. For example, asegmentation engine568 can divide logically sequential data (e.g., a data file) into multiple segments whose size can be, for example, equal to the channel chunk size determined by theinitialization engine566. In one implementation, thesegmentation engine568 can receive logically sequential data and can output segments that are sized according to the specified channel chunk sizes. Astriping engine570 then can control the striping of the logically sequential data to different channels of thedata storage device501 in first channel chunk size units. For example, anaddress assignment engine572 can assign a memory address to the data segments, where the assigned memory address specifies that the segment be written to a specific one of the physical channels of thestorage device501.
• Thestriping engine570 can tag each segment with an address (which may be assigned by the address assignment engine572) that will cause the particular segment to be written to aparticular channel513,523,533,543 that is indicted by the address. For example, a first channel chunk of data can be written tochannel513, a second channel chunk of data can be written tochannel523, a third channel chunk of data can be written tochannel533, and a fourth channel chunk of data can be written tochannel543. When a channel chunk size unit of data addressed to a particular channel (e.g., channel513) arrives at a channel controller (e.g., channel controller512) associated with the particular channel, then, if channel striping is used and the channel chunk size unit of data is not addressed to a particular flash memory chip connected to the channel, the channel controller can write portions of the channel chunk size unit to different flash memory chips. The individual flash memory chip selected for each portion can be determined dynamically (e.g., by the host550 or by the controller) based on the current run time state of each chip connected to the channel, e.g., based on the chip space availability of the chips connected to the channel. For example, if a write operation toflash memory chip514 is still being performed when a channel chunk size unit of data arrives atcontroller512, then the portions of the channel chunk size unit of data may be written toflash memory chips515,516, and517 until the write operation to chip514 is completed.
• Thus, by using channel striping when writing logically sequential data from the host to the storage device, data can be written to one channel while data is also being read from another channel. In addition, by using channel striping and dynamically determining the individual flash memory chips to which to write segments of logically sequential data within a particular channel, write performance of the system500 can be enhanced, because data will be written preferentially to chips that are most ready to accept the data, so the time the host is kept waiting for an chip to be accessible is kept to a minimum. Furthermore, because garbage collection in flash memory is a write-intensive process, channel striping can improve performance of garbage collection.
• An advantage of the host550 controlling the initialization and execution of the data striping is that the host can control and change the parameters that are used to perform data striping, so that the host can setup and control the interaction with thestorage device501. For example, the host550 may initially configure itself to use a first channel chunk size for striping data across different channels of thedata storage device501, but as a user's desires change, the apparatus500 is used for a different application, different flash memory chips are used in the storage device, etc., a need may arise for using a different channel chunk size for striping data across the channels. In this case, the initialization engine may be further configured to determine a second channel chunk size, different from the first channel chunk size, with which to write data to flash memory chips connected to separate channels. The segmentation engine can be further configured to segment logically sequential data into second channel chunk size segments, and the striping engine can be further configured to stripe data to different channels of the data storage device in second channel chunk size units.
• In addition to determining a channel chunk size with which to stripe logically sequential data across different channels in segments, the initialization engine also can determine a chip chunk size with which to stripe logically sequential data across different chips, where the chip chunk size determines the amount of data to be written to a particular chip before beginning to write data to a different chip. Then, when striping logically sequential data across particular chips (e.g.,chips514,515,516, and517 that are connected to a particular channel513) using “chip striping” the host can specify the destination memory address for a particular segment, where the specified address can include a particular chip to which the segment is to be written. With chip striping, logically sequential data can be striped across different chips of thestorage device501 in chip chunk size unit. That is, after a chip chunk size data segment has been written to one flash memory chip the next chip chunk size unit can be written to a different chip. Thus, chip striping provides maximum parallelism in read and write operations from and to thestorage device501. For example, in astorage device501 having40 channels and16 chips per channel, segments of a data file can be written to640 different chips before a chip is revisited. Therefore, chip striping offers advantages over channel striping in terms of read performance, because the high degree of parallelism that can be achieved with chip striping.
• Thus, with chip striping theinitialization engine566 can be configured to determine a first chip chunk size with which to write data to flash memory chips of thestorage device501. For example, based on information received from thestorage device501 about the number of flash memory chips in thestorage device501 and the page size used to write data to the flash memory chips, theinitialization engine566 may determine an appropriate channel chunk size to be some multiple of the page size (e.g., 8K, 32K, 40K, 80K, 160K, 320K, etc.).
• Then, when logically sequential data is written to thestorage device501 using a chip striping technique, the logically sequential data can be segmented in chip chunk size units for writing to the chips. For example, thesegmentation engine568 can divide logically sequential data (e.g., a data file) into multiple segments whose size can be, for example, equal to the chip chunk size determined by theinitialization engine566. In one implementation, thesegmentation engine568 can receive logically sequential data and can output segments that are sized according to the specified chip chunk sizes. Astriping engine570 then can control the striping of the logically sequential data to different chips of thedata storage device501 in chip chunk size units. For example, anaddress assignment engine572 can assign a memory address to the data segments, where the assigned memory address specifies that the segment be written to a specific one of the chips of thestorage device501.
• In another implementation, thesegmentation engine568 can receive logically sequential data and can output segments that are sized according to a specified channel chunk size and which are further subdivided into chip chunk size units. Thestriping engine570 then can control the striping of the logically sequential data to different channels of thedata storage device501 in channel chunk size units and can control the striping of data to chips connected to the channel in chip chunk size units. For example, theaddress assignment engine572 can assign a memory address to the data segments, where the assigned memory address specifies that the segment be written to a specific one of the channels and a specific one of the chips of thestorage device501.
• Thestriping engine570 can tag each segment with an address (which may be assigned by the address assignment engine572) that will cause the particular segment to be written to aparticular channel513,523,533,543 and to a particularflash memory chip514,515,516,517,524,525,526,527,534,535,536,537,544,545,546, and547 that is indicted by the address. For example, a first channel chunk of data can be written tochannel513, a second channel chunk of data can be written tochannel523, a third channel chunk of data can be written tochannel533, and a fourth channel chunk of data can be written tochannel543, whereas a first chip chunk of data of the first channel chunk can be written tochip514, a second chip chunk of data of the first channel chunk can be written tochip515, a third chip chunk of data of the first channel chunk can be written tochip516, and a fourth chip chunk of data of the first channel chunk can be written tochip517, and a first chip chunk of data of the second channel chunk can be written tochip524, a second chip chunk of data of the second channel chunk can be written tochip525, a third chip chunk of data of the second channel chunk can be written tochip526, and a fourth chip chunk of data of the second channel chunk can be written tochip527, etc.
• Thus, by using chip striping when writing logically sequential data from the host to the storage device, data can be written to one chip while data is also being read from another chip. Then, when the logically sequential is read back from the multiple chips of thestorage device501, read operations can be performed in parallel from the different flash memory chips.
• Partitioning and striping can be used in combination. For example, afirst partition104aof the flash memory chips in the storage device can be defined to use channel striping and asecond partition104bof the device can be defined to use chip striping. Thus, thefirst partition104amay provide relatively better write performance, redundancy, and fault tolerance due to the use of channel striping techniques to write and read data between the host and the first partition, while the second partition may provide relatively better read performance due to the use of chip striping techniques to write and read data between the host and the second partition.
• FIG. 6 is an exemplary flowchart illustrating example operations of the data storage device ofFIG. 5. Aprocess600 of striping data from a host to a data storage device is shown. The device includes a plurality of flash memory chips, and the data storage device includes a plurality of physical channels for communication of data between the host and the plurality of flash memory chips. Each channel is operably connected to a different plurality of the memory chips. A number of physical channels in the plurality of channels can be determined (602), for example, by theinitialization engine566. A first channel chunk size with which to write data to flash memory chips connected to separate channels can be determined (604), for example, by theinitialization engine566. Logically sequential data can be segmented into first channel chunk size segments by the host (606), for example, by thesegmentation engine568 running on the host550. Data can be striped to different channels of the data storage device in first channel chunk size units (608), for example, by thestriping engine570 in co-operation with theaddress assignment engine570.
• In one implementation, theprocess600 may further include determining a chip chunk size with which to write data to different flash memory chips (610), and, for each of the determined physical channels, determining a number of flash memory chips operably connected to the channel (612). Channel chunk size segments can be segmented into chip chunk size segments by the host (614), and data in a channel chuck sized unit can be striped to different flash memory chips connected to a channel in chip chunk size units (616).
• In another implementation, a second channel chunk size with which to write data to flash memory chips connected to separate channels can be determined (618) Logically sequential data can be segmented into second channel chunk size segments (620), and data can be striped to different channels of the data storage device in second channel chunk size units (622).
• Implementations of the various techniques described herein may be implemented in digital electronic circuitry, or in computer hardware, firmware, software, or in combinations of them. Implementations may be implemented as a computer program product, i.e., a computer program tangibly embodied in an information carrier, e.g., in a machine-readable storage device, for execution by, or to control the operation of, data processing apparatus, e.g., a programmable processor, a computer, or multiple computers. A computer program, such as the computer program(s) described above, can be written in any form of programming language, including compiled or interpreted languages, and can be deployed in any form, including as a stand-alone program or as a module, component, subroutine, or other unit suitable for use in a computing environment. A computer program can be deployed to be executed on one computer or on multiple computers at one site or distributed across multiple sites and interconnected by a communication network.
• Method steps may be performed by one or more programmable processors executing a computer program to perform functions by operating on input data and generating output. Method steps also may be performed by, and an apparatus may be implemented as, special purpose logic circuitry, e.g., a FPGA or an ASIC (application-specific integrated circuit).
• Processors suitable for the execution of a computer program include, by way of example, both general and special purpose microprocessors, and any one or more processors of any kind of digital computer. Generally, a processor will receive instructions and data from a read-only memory or a random access memory or both. Elements of a computer may include at least one processor for executing instructions and one or more memory devices for storing instructions and data. Generally, a computer also may include, or be operatively coupled to receive data from or transfer data to, or both, one or more mass storage devices for storing data, e.g., magnetic, magneto-optical disks, or optical disks. Information carriers suitable for embodying computer program instructions and data include all forms of non-volatile memory, including by way of example semiconductor memory devices, e.g., EPROM, EEPROM, and flash memory devices; magnetic disks, e.g., internal hard disks or removable disks; magneto-optical disks; and CD-ROM and DVD-ROM disks. The processor and the memory may be supplemented by, or incorporated in special purpose logic circuitry.
• To provide for interaction with a user, implementations may be implemented on a computer having a display device, e.g., a cathode ray tube (CRT) or liquid crystal display (LCD) monitor, for displaying information to the user and a keyboard and a pointing device, e.g., a mouse or a trackball, by which the user can provide input to the computer. Other kinds of devices can be used to provide for interaction with a user as well; for example, feedback provided to the user can be any form of sensory feedback, e.g., visual feedback, auditory feedback, or tactile feedback; and input from the user can be received in any form, including acoustic, speech, or tactile input.
• Implementations may be implemented in a computing system that includes a back-end component, e.g., as a data server, or that includes a middleware component, e.g., an application server, or that includes a front-end component, e.g., a client computer having a graphical user interface or a Web browser through which a user can interact with an implementation, or any combination of such back-end, middleware, or front-end components. Components may be interconnected by any form or medium of digital data communication, e.g., a communication network. Examples of communication networks include a local area network (LAN) and a wide area network (WAN), e.g., the Internet.
• While certain features of the described implementations have been illustrated as described herein, many modifications, substitutions, changes and equivalents will now occur to those skilled in the art. It is, therefore, to be understood that the appended claims are intended to cover all such modifications and changes as fall within the scope of the embodiments.

Claims (21)

1-23. (canceled)

24. A method comprising:

transmitting, from a data storage device to a host device via an interface, information indicating a number of flash memory chips in the data storage device, a first portion of the flash memory chips being implemented in a first memory channel and a second portion of the flash memory chips being implemented in a second memory channel;

defining, by the host, a first data storage partition of the data storage device, the first data storage partition including a first subset of the flash memory chips, the first subset having one or more flash memory chips of the first memory channel and one or more flash memory chips of the second memory channel;

defining, by the host, a second data storage partition of the data storage device, the second data storage partition including a second subset of the flash memory chips that does not include any flash memory chips of the first subset, a boundary between the first partition and second partition being defined by the first subset of the flash memory chips and the second subset of the flash memory chips;

providing, via the interface, first data from the host to the data storage device;

writing the first data to the first partition while reading data from the second partition; and

writing the first data to the second partition while reading data from the first partition.

25. That method ofclaim 24, wherein the interface includes a PCIe interface.

26. The method ofclaim 24, further comprising:

providing, via the interface, second data from the host device to the data storage device;

writing second data to the first partition, while reading data from the second partition;

writing the second data to the second partition while reading data from the first partition; and

for N=3rd to at least 10th:

providing, via the interface, N data from the host to the data storage device;

writing the N data to the first partition while reading data from the second partition; and

writing the N data to the second partition while reading data from the first partition.

27. The method ofclaim 24, wherein the transmitted information includes information about a physical architecture of the data storage device, including information about connections between particular flash memory chips and particular channels of the data storage device.

28. The method ofclaim 24, further comprising determining, by the host, an address location in the data storage device to which to write data from the host, the address location specifying that the data from the host be written to a specific one of the flash memory chips.

29. The method ofclaim 24, further comprising:

determining a number of physical channels for communication of data between the host and the flash memory chips, each physical channel being operably connected to a different plurality of the flash memory chips;

determining a first subset of the physical channels, wherein physical channels of the first subset of physical channels are operably connected only to flash memory chips of the first subset of the flash memory chips; and

determining a second subset of the physical channels, wherein physical channels of the second subset of physical channels are operably connected only to flash memory chips of the second subset of the flash memory chips.

30. The method ofclaim 24, further comprising:

receiving, via the interface, an indication from the data storage device to the host that a flash memory chip of the first partition has failed or is likely to fail;

re-defining, by the host, the first partition of the data storage device to include a third subset of the flash memory chips,

the third subset of the flash memory chips being different from the first subset of the flash memory chips, and

the third subset of the flash memory chips not including any flash memory chips of the second subset.

31. The method ofclaim 30, wherein re-defining the first partition includes defining the third subset of the flash memory chips as the first subset of the flash memory chips but for the flash memory chip that has failed or that is approaching failure.

32. An apparatus comprising:

a flash memory data storage device including a plurality of flash memory chips, a first portion of the plurality of flash memory chips being implemented in a first memory channel and a second portion of the plurality of flash memory chips being implemented in a second memory channel;

an interface; and

a host operably coupled to the data storage device via the interface, the host comprising:

a configuration detection engine configured to determine, by communicating with the data storage device over the interface, a number of flash memory chips in the data storage device;

a partition engine configured to define a first partition of the data storage device and a second partition of the data storage device, the first partition including a first subset of the plurality of flash memory chips having one or more flash memory chips of the first memory channel and one or more flash memory chips of the second memory channel, the second partition including a second subset of the plurality of flash memory chips that does not include any flash memory chips of the first subset of the plurality of flash memory chips, a boundary between the first partition and the second partition being defined by the first subset of the plurality of flash memory chips and the second subset of the plurality flash memory chips.

33. The apparatus ofclaim 32, wherein:

the driver is further configured to transmit second data to the data storage device; and

the data storage device is configured to:

write the second data to the first partition while reading data from the second partition; and

write the second data to the second partition while reading data from the first partition.

34. The apparatus ofclaim 32, wherein the data storage device is configured to transmit, via the interface upon receiving a command from the host, information from the data storage device to the host indicating the number of flash memory chips in the data storage device.

35. The apparatus ofclaim 34, wherein the transmitted information includes information about physical architecture of the data storage device, including information about connections between particular flash memory chips and particular channels of the data storage device.

36. The apparatus ofclaim 32, wherein the host further comprises an address assignment engine configured to assign a memory address to data to be written to the data storage device, wherein the assigned memory address specifies that the data be written is to a specific one of the plurality of flash memory chips.

37. The apparatus ofclaim 32, wherein:

the configuration detection engine is further configured, by communication with the data storage device via the interface, to detect a number of physical channels of the data storage device; and

the partition engine is further configured to:

determine a first subset of the number of physical channels, channels of the first subset of physical channels being operably connected only to flash memory chips of the first subset of the plurality of flash memory chips; and

determine a second subset of the number of physical channels, channels of the second subset of physical channels being operably connected only to flash memory chips of the second subset of the plurality of flash memory chips.

38. The apparatus ofclaim 32, wherein the second partition only includes flash memory chips that are operably connected to the second memory channel.

39. The apparatus ofclaim 32, wherein the partition engine is further configured to:

receive, via the interface, an indication from the data storage device that a flash memory chip of the first partition has failed or is likely to fail; and

re-define the first partition of the data storage device to include a third subset of the plurality of flash memory chips, the third subset of the plurality of flash memory chips being different from the first subset of the plurality of flash memory chips and not including any flash memory chips of the second subset.

40. The apparatus ofclaim 39, wherein re-defining the first partition to include the third subset of the plurality of flash memory chips includes defining the third subset as the first subset of the plurality of flash memory chips but for the flash memory chip that has failed or that is approaching failure.

41. The apparatus ofclaim 32, wherein the interface includes a PCIe interface.

42. The apparatus ofclaim 41, wherein the PCIe interface includes a PCIe x4 interface.

43. The apparatus ofclaim 41, wherein the PCIe interface includes a PCIe x8 interface.

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