Abstract:
A composite solid state drive control system, composed of a redundant array of independent disks (RAID) formed by SD Cards, and multi-channel Flash Memory. Wherein, at least a RAID control unit combines a plurality of relatively inexpensive SD Cards into a set of redundant arrays of independent disks (RAIDs), so that its storage capacity can reach or even surpass a costly and huge capacity SD Card. Through controlling data transmission and accessing between at least a flash memory control unit and at least a SD Card control unit, data read and write speeds can be increased, and back-up redundant data can be made, hereby achieving stable operations of an electronic computing device by means of highly stable Flash Memory.

Description:
BACKGROUND OF THE INVENTION 
       [0001]    1. Field of the Invention 
         [0002]    The present invention relates to a solid state drive control system, and in particular to a composite solid state drive control system composed of redundant array of independent disks (RAID) formed by SD Cards, and multi-channel flash memory. 
         [0003]    2. The Prior Arts 
         [0004]    Along with the progress and development of computer technology, the demand for larger data storage capacity of personal computer, notebook computer, and personal memory device has been increasing rapidly. Meanwhile, for the conventional data storage device such as hard disk, due to its shortcomings of inferior expandability, and is liable to generate heat and vibrations during operations, so it is gradually forced out of the market, and is replaced by solid state data storage device. Presently, among the various solid state data storage devices available, such as Flash Memory, Memory Stick, SD (Secure Digital) Card, IDE Flash Hard Disk Drive, SATA Flash Hard Disk Drive, etc., the technology for Flash Memory has reached a fairly mature level, so quite a lot of data storage devices adopt Flash Memory to replace the conventional hard disk. However, the shortcomings of Flash Memory is that it price is rather high, such that in producing a data storage device, in order to fulfill user&#39;s demand, and if only high price flash memory is utilized, then its cost will increase proportionally to the data transmission speed and data storage capacity of the flash memory. In other words, the faster its data transmission speed and the larger its data storage capacity, the higher is the cost for the Flash Memory. Otherwise, in case that only SD Cards of lower cost are utilized in combination with the solid state hard disk, then the data storage device thus produced can only provide convenience in application, but it can not guarantee the high stability required for an electronic computing device. 
         [0005]    In the past, as in the prior art, a method of utilizing redundant array of independent disks (RAID) is proposed, and that is used to raise the data access speed of an electronic computing device. The redundant array of independent disks (RAID) method is able to combine a plurality of sub-access devices into an access device, and in executing data accessing, data is partitioned into a plurality of parts, and then they are accessed by the plurality of sub-access devices in parallel simultaneously, so the RAID method is able to achieve faster data access speed. Refer to  FIG. 1  for a schematic block diagram of a Flash Storage Chip and Flash Array Storage System according to the prior art, by way of example, Taiwan Patent Publication Number 200910356 discloses a Flash Storage Chip and Flash Array Storage System, which is characterized in utilizing PCI Express standard as an electrical interface of the data transmission interface  10 , and wherein a flash array controller  12  is used to combine a plurality of flash storage chips  14  to achieve faster data access speed. However, as mentioned above, the price of a data storage device incorporating RAID and Flash Memory is rather too high. Therefore, presently, how to realize high data access speed, large data storage capacity expandability, and high stability, while achieving cost effectiveness for the solid state hard disk, is the most urgent task in this field. 
         [0006]    Therefore, presently, the design and performance of solid state hard disk of the prior art is not quite satisfactory, and it has much room for improvement. 
       SUMMARY OF THE INVENTION 
       [0007]    In view of the problems and shortcomings of the prior art, the present invention proposes a composite solid state drive control system, which utilizes functions of RAID to speed up reading of SD Card in achieving cost effectiveness, and it incorporates Flash Memory in realizing operation stability, thus achieving both stability and cost-effectiveness of a data storage device. 
         [0008]    A major objective of the present invention is to provide a composite solid state drive control system, incorporating multi-channel Flash Memory and utilizing redundant array of independent disks (RAID) to speed up the reading or writing a plurality of expandable SD Cards, so that its function is able to reach or even surpass that of a costly and huge capacity SD Card. In addition, a highly stable Flash Memory is used to achieve operation stability and cost effectiveness of an electronic computing device, hereby realizing a composite solid state hard disk control system or composite solid state hard disk control chip having a SATA or PATA transmission interface. 
         [0009]    Another objective of the present invention is to provide a composite solid state drive control system, wherein, the redundant array of independent disks (RAID) is used to control the speed-up of data reading and writing speeds while making a redundant copy for safety reasons. For example, the hard disk partition technology of RAID can be used to store data into separate SD Cards, so that when data on a SD Card is damaged, it can be restored by the corresponding data on the redundant SD Card. 
         [0010]    A further objective of the present invention is to provide a composite solid state drive control system, so that a plurality of SD Cards can be used to achieve high expandability of data storage capability. 
         [0011]    In order to achieve the above-mentioned objective, the present invention provide a composite solid state drive control system, connected electrically to an electronic computing device, comprising: at least a flash memory control unit, at least a SD Card control unit, and at least a RAID control unit. The electronic computing device includes at least a programmable read only memory (PROM), at least a central processor unit, and at least a random access memory (RAM) control unit. Wherein, the programmable read only memory (PROM) is connected electrically to at least a central processor unit (CPU) to provide instructions, the central processor unit is connected electrically to at least a random access memory (RAM) control unit for accessing data stored on the at least a RAM. After interpreting instructions as read from the PROM, the central processor unit (CPU) manages and controls the data transmission between the flash memory control unit, the RAID control unit, the SD Card control unit, and SATA or PATA interface control unit. Since the control unit having RAID functions is able to combine a plurality of SD Cards into a logic magnetic region, the Operation System treats them only as a unitary SD Card, therefore, the composite solid state drive control system of the present invention provides a way of combining Flash Memory and SD Cards through using redundant array of independent disks (RAID), so as to achieve both operation stability and cost effectiveness by making use of the highly stable Flash Memory and low cost SD Cards. 
         [0012]    Further scope of the applicability of the present invention will become apparent from the detailed description given hereinafter. However, it should be understood that the detailed description and specific examples, while indicating preferred embodiments of the present invention, are given by way of illustration only, since various changes and modifications within the spirit and scope of the present invention will become apparent to those skilled in the art from this detailed description. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0013]    The related drawings in connection with the detailed description of the present invention to be made later are described briefly as follows, in which: 
           [0014]      FIG. 1  is a schematic block diagram of a flash storage chip and flash array storage system according to the prior art; and 
           [0015]      FIG. 2  is a schematic block diagram of a composite solid state drive control system according to the present invention. 
       
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
       [0016]    The purpose, construction, features, functions and advantages of the present invention can be appreciated and understood more thoroughly through the following detailed description with reference to the attached drawings. And, in the following, various embodiments are described in explaining the technical characteristics of the present invention. 
         [0017]    Refer to  FIG. 2  for a schematic block diagram of a composite solid state drive control system according to the present invention. As shown in  FIG. 2 , the composite solid state drive control system  16  is connected electrically to an electronic computing device  18 , comprising: a flash memory control unit  28 , a RAID control unit  30 , and a SD Card control unit  32 . Moreover, the electronic computing device  18  includes a central processor unit  24 , a random access memory (RAM) control unit  20 , a direct memory access (DMA) control unit  26 , a programmable read-only-memory (PROM)  22 , and a SATA or PATA control unit  25 . The composite solid state drive control system  16  is applicable to the electronic computing device  18 , such as a personal computer, a notebook computer, or a personal memory device, for combining flash memory  38  and a plurality of expandable SD Cards  40 . In the electronic computing device  18 , at least a PROM  22  is connected electrically to at least a central processor unit (CPU)  24  to provide the instructions required. The central processor unit  24  is connected electrically to a RAM control unit  20 , so that after receiving instructions from PROM  22  and interpreting the instructions, the central processor unit  24  performs data accessing to at least a random access memory (RAM)  36 . In the present embodiment, a plurality of random access memories (RAMs)  36  are taken as an example, such that central processor unit  24  controls and coordinates data transmissions among a flash memory control unit  28 , a RAID control unit  30 , a SD Card control unit.  32 , and a SATA or PATA control unit  25 . The random access memory (RAM)  36  utilized can be a dynamic random access memory (DRAM) or a static random access memory (SRAM). 
         [0018]    The electronic computing device  18  includes a direct memory access control unit  26 , connected electrically to at least a RAM control unit  20 , at least a SATA or PATA control unit  25 , at least a flash memory control unit  28 , at least a RAID control unit  30 , and at least a SD Card control unit.  32 , so as to achieve direct data reading and writing. Wherein, the input or output interface can be serial advanced technology attachment (SATA), integrated device electronics (IDE) or parallel ATA (PATA), or external serial ATA (eSATA). 
         [0019]    The flash memory control unit  28  is connected electrically to central processor unit  24 , such that it utilizes Single Channel technology or Multi-Channel technology to transmit data, and it is capable of providing Error Correction Code (ECC) to correct data. The flash memory control unit  28  is connected electrically to at least a flash memory  38 , which can be implemented by means of a System-In-Package (SIP) way. The flash memory  38  can be a NAND type flash memory or a NOR type flash memory, and is of a Single Level Cell (SLC) specification or a Multi-Level Cell (MLC) specification respectively. 
         [0020]    The SD Card control unit  32  is connected electrically to the central processor unit  24  and a plurality of insertion slots  34 , and each insertion slot corresponds to a secure digital (SD) Card  40 . The RAID control unit  30  controls at least two SD Cards  40  to raise the reading and writing speed of the SD Cards through the RAID, and it controls and coordinates data transmission and storage among flash memory control unit  28 , SD Card control unit.  32 , and SATA or PATA control unit  25 . In addition, the RAID hard disk partition technology is used to store the corresponding data into the respective SD Card  40 , such that when data on a SD Card is damaged, it can be restored by the corresponding data on the redundant SD Card, in achieving data backup for safety reasons. The SD Card  40  utilized can be classified into micro SD card (Trans Flash card), mini SD Card, SDHC (High-Capacity) card, or SDXC (eXtended-Capacity) card. 
         [0021]    The array functions of RAID control unit  30  can be classified into the following modes: JBOD, RAID0, RAID1, RAID2, RAID3, RAID4, RAID5, RAID6, RAID7, RAID1+0, RAID0+1, RAID50, RAID53. In the preferred embodiments of the present invention, two modes are utilized for explanation, which are described as follows (in the following, min means the minimum capacity of SD Card, and n and m mean number of SD Cards). 
       Mode 1 
       [0022]    The flash memory  38  is combined with SD Card  40 , such that they are considered as a unitary disk device, thus the capacity calculations in response to the SATA or PATA transmission interface  42  are as follows:
   1. SD Card adopting JBOD mode: Flash+SD Card 0 +SD Card 1 + . . . +SD Card n−1 +SD Card n , namely, the capacity of one flash memory  38  plus the capacities of n SD cards  40 ;   2. SD Card adopting RAID 1 mode: Flash+min(SD Card 0            SD Card 1            . . .           SD Card n ), namely, the capacity of one flash memory  38  plus the minimum of the capacities of n SD Cards  40 ;   3. SD Card adopting RAID 0 mode: Flash+min(SD Card 0            SD Card 1 )*2+min(SD Card 2            SD Card 3 )*2+ . . . +min(SD Card n−1            SD Card n )*2, namely, the capacity of one flash memory  38  plus the sum of two times the minimum capacity of every two SD Cards  40 ;   4. SD Card adopting RAID 10 mode: Flash+min(SD Card 0            SD Card 1 )+min(SD Card 2            SD Card 3 )+ . . . +min(SD Card n−1            SD Card n ): namely, the capacity of one flash memory  38  plus the sum of the minimum capacity of every two SD Cards  40 ; and   5. SD Card adopting RAID 5 mode: Flash+min(SD Card 0            SD Card 1            . . .           SD Card n ) (n−1); namely, the capacity of one flash memory  38  plus (n−1) times the minimum capacity of the n SD Cards  40 .   
 
         [0028]    According to an embodiment of the present invention, data writing is carried out in the following way: upon receiving a data write instruction by a SATA or PATA control unit  25  via a SATA or PATA transmission interface  42 , the central processor unit  24  starts calculating and figuring out the device for writing and storing data, then under the control of memory access (DMA) control unit  26 , data is transmitted from the SATA or PATA transmission interface  42  to SATA or PATA control unit  25 , and then it is transmitted to and stored in random access memory  36  via DMA control unit  26 . Subsequently, in case it is determined by the central processor unit  24  that the data should be written and stored in the flash memory  38 , then data is transmitted from the random access memory  36  to the flash memory  38  under the control of direct memory access (DMA) control unit  26 . Or, alternatively, in case it is determined by the central processor unit  24  that the data should be written and stored in SD Cards  40 , then data is transmitted from the random access memory  36  to a proper SD Card  40  via a RAID control unit  30  according to the selected RAID mode. 
         [0029]    Furthermore, according to an embodiment of the present invention, data reading is carried out in the following way: upon receiving a data read instruction by a SATA or PATA control unit  25  via a SATA or PATA transmission interface  42 , the central processor unit  24  starts calculating and figuring out the device from which the data is to be read, if it is determined by the central processor unit  24  that data should be read from the flash memory  38 , then the direct memory access (DMA) control unit  26  retrieves data from the flash memory  38  and stores it into random access memory  36 , and then transmits the data stored therein via DMA control unit  26  to the SATA or PATA control unit  25 , and then to the SATA or PATA transmission interface  42 . Or, alternatively, in case it is determined by the central processor unit  24  that the data should be read from the SD Cards  40 , then the RAID control unit  30  retrieves data from the SD Cards  40 , and transmits the data to random access memory  36  via direct memory access control unit  26 , then transmits the data stored therein via DMA control unit  26  to the SATA or PATA control unit  25 , and then to the SATA or PATA transmission interface  42 . 
       Mode 2 
       [0030]    The flash memory  38  is combined with SD Card  40 , such that user may view at the same time both a separate disk device of flash memory  38  and a separate disk device of SD Card  40 , since both the disk devices are separate and independent, so the storage capacity of each SD Card  40  can be obtained based on the RIAD mode as described as follows:
       1. SD Card adopting JBOD mode: the total capacity is the sum of capacities of all the SD Cards, such that all the SD Cards are viewed as a unitary device, with the total capacity as SD Card n +SD Card n+1 + . . . +SD Card n+m-1 +SD Card n+m ; namely, the sum of capacities of n SD Cards  40  plus sum of capacities of m SD Cards.   The total number of Flash Devices and SD Card JBOD Devices can be varied depending on the interface utilized:   i. When adopting PATA, only one set of Flash Devices and one set of SD Card JBOD Devices can be provided, such that the Flash Device is the Master, the SD Card JOBD Device is the Slave; or, alternatively, the Flash Device is the Slave, and the SD Card JBOD Device is the Master; and   ii. When adopting SATA, through utilizing RAID control unit  30 , one set of Flash Devices and fourteen sets of SD Card JBOD Devices can be set up at most.   2. SD Card adopting RAID1 mode: every two SD Cards are viewed as a unitary device, such that the capacity of each device is min(SD Card n−1            SD Card n ).   The total number of Flash Devices and SD Card RAID 1 Devices can be varied depending on the interface utilized as explained as follows:   i. When adopting PATA, only one set of Flash Devices and one set of SD Card RAID 1 Devices can be provided, such that the Flash Device is the Master, the SD Card RAID 1 Device is the Slave; or, alternatively, the Flash Device is the Slave, and SD Card RAID1 Device is the Master; and   ii. When adopting SATA, through utilizing RAID control unit  30 , one set of Flash Devices and fourteen sets of SD Card RAID1 Devices can be set up at most.   3. SD Card adopting RAID0 mode: every two SD Cards are viewed as a unitary device, such that the capacity of each device is min(SD Card n , SD Card n+1 )*2.   The total number of Flash Devices and SD Card RAID 0 Devices can be varied depending on the interface utilized as explained as follows:   i. When adopting PATA, only one set of Flash Devices and one set of SD Card RAID 0 Devices can be provided, such that the Flash Device is the Master, the SD Card RAID 0 Device is the Slave; or, alternatively, the Flash Device is the Slave, and the SD Card RAID0 Device is the Master; and   ii. When adopting SATA, through utilizing RAID control unit  30 , one set of Flash Devices and fourteen sets of SD Card RAID0 Devices can be set up at most.   4. SD Card adopting RAID 10 mode: every four SD Cards are viewed as a unitary device, such that the capacity of each device is min(SD Card n             SD Card n+1 )+min(SD Card n+2            SD Card n+3 ).   The total number of Flash Devices and SD Card RAID 10 Devices can be varied depending on the interface utilized as explained as follows:   i. When adopting PATA, only one set of Flash Devices and one set of SD Card RAID 10 Devices can be provided, such that the Flash Device is the Master, the SD Card RAID 10 Device is the Slave; or, alternatively, the Flash Device is the Slave, and the SD Card RAID10 Device is the Master; and   ii. When adopting SATA, through utilizing RAID control unit  30 , one set of Flash Devices and fourteen sets of SD Card RAID 10 Devices can be set up at most.   5. SD Card adopting RAID5 mode: every three SD Cards are viewed as a unitary device, such that the capacity of each device is min(SD Card n             SD Card n+1            . . .           SD Card n+m-1 , SD Card n+m )*(m−1).   The total number of Flash Devices and SD Card RAID 5 Devices can be varied depending on the interface utilized as explained as follows:   i. When adopting PATA, only one set of Flash Devices and one set of SD Card RAID 5 Devices can be provided, such that the Flash Device is the Master, the SD Card RAID 5 Device is the Slave; or, alternatively, the Flash Device is the Slave, and the SD Card RAID 5 Device is the Master; and   ii. When adopting SATA, through utilizing RAID control unit  30 , one set of Flash Devices and fourteen sets of SD Card RAID 5 Devices can be set up at most.       
 
         [0051]    The way of data reading and writing of mode 2 is the same as that of mode 1, and it will not be repeated here for brevity. 
         [0052]    The present invention provides a composite solid state drive control system  16 , which combines the Flash Memory  38  and a plurality of SD Cards  40 , so that the function of the plurality of SD Cards  40  can reach or even surpass an expensive and huge capacity SD Card  40 , as such the highly stable Flash Memory  38  is utilized to make an electronic computing device  18  stable and cost effective, while making use of the high expandability of the SD Cards  40 . 
         [0053]    The above detailed description of the preferred embodiment is intended to describe more clearly the characteristics and spirit of the present invention. However, the preferred embodiments disclosed above are not intended to be any restrictions to the scope of the present invention. Conversely, its purpose is to include the various changes and equivalent arrangements which are within the scope of the appended claims.