Patent Publication Number: US-2011063750-A1

Title: System and method to control spin-up of storage device

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application claims the benefit under 35 U.S.C. §119(a) of Korean Patent Application No. 10-2009-0086936, filed on Sep. 15, 2009, in the Korean Intellectual Property Office, the disclosure of which is incorporated herein in its entirety by reference. 
     BACKGROUND 
     1. Field of the Invention 
     The present general inventive concept relates to a storage device spin-up control system and method, and more particularly, to a system and method of selectively controlling a spin-up mode of a storage device based on the level of a signal output from a power connector. 
     2. Description of the Related Art 
     Storage devices such as hard disk drives (HDD) have been widely used in a variety of digital devices, including desktop personal computers and laptop computers. However, with the wider use of such storage devices, spin-up failure frequently occurs due to insufficient power supply from a host or variations in power supply, and thus a storage device is more likely to not be recognized. A spin-up failure is a failure of the hard disk to achieve a rotation velocity sufficient to perform a read/write operation from/to the hard disk. In order to address these problems, various methods of successfully spinning up a storage device in connection with a host supplying insufficient power by using firmware have been applied. However, the storage device may not be able to obtain information on power supplied from the host, and thus may not be able to determine which of methods may be applicable to a host. 
     SUMMARY 
     The present general inventive concept selectively controls a spin-up mode of a storage device based on the level of a signal output from a power connector of an interface linking a host and the storage device. 
     Additional features and utilities of the present general inventive concept will be set forth in part in the description which follows and, in part, will be obvious from the description, or may be learned by practice of the general inventive concept. 
     Features and/or utilities of the present general inventive concept may be realized by a storage device spin-up control system including a storage device to store data, a host to selectively control a spin-up mode of the storage device, and an interface to link the storage device and the host. The host may control the spin-up mode of the storage device based on a level of a signal output from a power connector of the interface. 
     The host may include a power connector signal level detection unit that detects the level of the signal output from the power connector and outputs a corresponding signal. 
     The host may include a current control unit that controls the spin-up mode of the storage device based on the level of the signal detected by the power connector signal level detection unit. 
     The current control unit may spin up the storage device in a normal current mode if the signal output from the power connector level detection unit is at a first logic level, and may spin up the storage device in a low current mode if the signal output from the power connector level detection unit is at a second logic level. 
     The power connector signal level detection unit may include a first detection unit to detect a maximum current that can be supplied from the host to spin up the storage device, a second detection unit to detect a threshold current required for the storage device to spin up, a comparison unit to compare the maximum current detected by the first detection unit and the threshold current detected by the second detection unit, and an output unit to output a signal corresponding to the level of the signal of the power connector at a first logic level if the maximum current is greater than the threshold current, and to output a signal corresponding to the level of the signal of the power connector at a second logic level if the maximum current is less than the threshold current. 
     The host may include an automatic mode switching unit that determines whether the storage device has been successfully spun up by using a current supplied from a power supply unit of the host, and that controls the spin-up mode of the storage device based on the level of the signal output from the power connector exclusively when the storage device fails to spin up. 
     The storage device spin-up control system may further include a manual mode switching unit, and the host may control the spin-up mode of the storage device exclusively when the manual mode switching unit is selected by a user. 
     The host may spin up the storage device in a normal current mode if the manual mode switching unit is not selected by the user, and the host may spin up the storage device in a low current mode if the manual mode switching unit is selected by the user. 
     The manual mode switching unit may include an external switch located outside the host. 
     The interface may include a Serial Advanced Technology Attachment (SATA) interface, and the power connector may include a power pin  11  of the SATA interface. 
     Features and/or utilities of the present general inventive concept may also be realized by a storage device spin-up control system including N storage devices to store data, where N is a natural number of 2 or greater, a host to selectively control spin-up modes of the N storage devices, and an interface to link the N storage devices and the host. The host may include a staggered spin-up (SSU) control unit to control sequentially spinning up of the N storage devices, and the host may control the spin-up modes of the N storage devices based on a level of a signal output from a power connector of the interface. 
     The host may include a power connector signal level detection unit that detects the level of the signal output from the power connector and outputs a corresponding signal. 
     The host may include a current control unit that controls a spin-up mode of an n th  storage device based on the level of the signal detected by the power connector signal level detection unit, where n is a natural number from 1 to N used to denote one of the N storage devices. 
     The current control unit may spin up the n th  storage device in a normal current mode if the signal output from the power connector level detection unit is at a first logic level and may spin up the n th  storage device in a low current mode if the signal output from the power connector level detection unit is at a second logic level. 
     Features and/or utilities of the present general inventive concept may also be realized by a storage device spin-up control method including linking a host and a storage device, detecting a level of a signal output from a power connector of an interface linking the host and the storage device, and controlling a spin-up mode of the storage device based on the detected level of the signal. 
     The controlling of the spin-up mode of the storage device may include spinning up the storage device in a normal current mode if the signal output from the power connector is at a first logic level and spinning up the storage device in a low current mode if the signal output from the power connector is at a second logic level. 
     The detecting of the level of the signal may include detecting a maximum current that can be supplied from the host to spin up the storage device, detecting a threshold current required for the storage device to spin up, comparing the maximum current and the threshold current, and outputting a signal corresponding to the level of the signal output from the power connector at a first logic level if the maximum current is greater than the threshold current and outputting a signal corresponding to the level of the signal output from the power connector at a second logic level if the maximum current is less than the threshold current. 
     Features and/or utilities of the present general inventive concept may also be realized by a storage device spin-up control method including controlling sequential spinning up of N storage devices, where N is a natural number of 2 or greater, linking a host and an n th  storage device, where the n th  storage device is one of the N storage devices and n is a natural number from 1 to N, detecting a level of a signal output from a power connector of an interface linking the host and the N storage devices, and controlling a spin-up mode of the n th  storage device based on the detected level of the signal. 
     The controlling of the spin-up mode of the n th  storage device may include spinning up the nth storage device in a normal current mode if the signal output from the power connector is at a first logic level, and spinning up the n th  storage device in a low current mode if the signal output from the power connector is a second logic level. 
     The detecting of the level of the signal may include detecting a maximum current that can be supplied from the host to spin up the N storage devices, detecting a threshold current required for the n th  storage device of the N storage devices to spin up, comparing the maximum current and the threshold current of the n th  storage device, and outputting a signal corresponding to the level of the signal output from the power connector at a first logic level if the maximum current is greater than the threshold current required for the n th  storage device to spin up and outputting a signal corresponding to the level of the signal of the power connector at a second logic level if the maximum current is less than the threshold current required for the n th  storage device to spin up. 
     Features and/or utilities of the present general inventive concept may also be realized by a data storage device including a hard disk drive and a hard disk drive control unit to control a spin-up operation of the hard disk drive. The hard disk drive control unit may supply a first current to the hard disk drive to perform a first spin-up operation when a detected power level to the hard disk drive is a first level, and the hard disk drive control unit may supply a second current less than the first current to the hard disk drive to perform a second spin-up operation when a detected power level to the hard disk drive is a second level less than the first level. 
     The hard disk drive control unit may include a power supply unit to supply power to the hard disk drive to perform the spin-up operation, a current control unit to supply the first and second current to the hard disk drive, and a power level detection unit to detect the power level supplied to the hard disk drive. 
     The power level detection unit may include a first detection unit to detect a threshold current level required by the hard disk drive to perform the first spin-up operation, a second detection unit to detect the power level supplied to the hard disk drive, a comparison unit to compare a power level corresponding to the current level detected by the first detection unit and the power level supplied to the hard disk drive, and an output unit to output a power level detection signal to the current control unit. 
     The output unit may output the power level detection signal on a connection pin of the hard disk drive control unit that is used to control a staggered spin-up of the hard disk drive. 
     Features and/or utilities of the present general inventive concept may also be realized by a computing device including a hard disk drive, a hard disk drive control unit to control a spin-up operation of the hard disk drive, a controller to control operation of the hard disk drive and the hard disk drive control unit, and at least one interface to cause the controller to control operation of the hard disk drive and the hard disk drive control unit. The hard disk drive control unit may supply a first current to the hard disk drive to perform a first spin-up operation when a detected power level to the hard disk drive is a first level, and the hard disk drive control unit may supply a second current less than the first current to the hard disk drive to perform a second spin-up operation when a detected power level to the hard disk drive is a second level less than the first level. 
     The at least one interface may include a user interface to receive a user input to access the hard disk drive. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The above and other features and advantages of the present general inventive concept will become more apparent by describing in detail exemplary embodiments thereof with reference to the attached drawings in which: 
         FIGS. 1 and 2  are block diagrams of a storage device spin-up control system according to an embodiment of the present general inventive concept; 
         FIG. 3  is a block diagram of a power connector signal level detection unit of a host in  FIG. 1 , according to an embodiment of the present general inventive concept; 
         FIG. 4A  is a timing diagram illustrating the level of a signal output from a power connector of an interface, and  FIG. 4B  is a timing diagram illustrating the level of a signal output from a power connector of an interface when spin-up current is controlled by the storage device spin-up control system of  FIGS. 1 and 2 ; 
         FIG. 5A  is a graph of current supplied to a storage device from a host with respect to time when a maximum current is greater than a threshold current, and  FIG. 5B  is a graph of current supplied to the storage device from the host with respect to time when the maximum current is less than the threshold current; 
         FIG. 6  is a block diagram of a storage device spin-up control system according to another embodiment of the present general inventive concept, wherein an automatic mode switching unit is further included; 
         FIG. 7  is a block diagram of a storage device spin-up control system according to another embodiment of the present general inventive concept, wherein a manual mode switching unit is further included; 
         FIG. 8  is a block diagram of a storage device spin-up control system according to another embodiment of the present general inventive concept, wherein an automatic mode switching unit and a manual mode switching unit are further included; 
         FIG. 9  is a block diagram of a storage device spin-up control system to control spin-up of a plurality of storage devices according to another embodiment of the present general inventive concept; 
         FIG. 10A  is a timing diagram illustrating the level of a signal output from a power connector of an interface when spinning up a plurality of storage devices, and  FIG. 10B  is a timing diagram illustrating the level of a signal output from a power connector of an interface when spin-up current is controlled to spin up a plurality of storage device by the storage device spin-up control system of  FIG. 9 ; 
         FIG. 11  is a block diagram of a storage device spin-up control system of controlling spin-up of a plurality of storage devices according to another embodiment of the present general inventive concept, wherein an automatic mode switching unit is further included in a host; 
         FIG. 12  is a block diagram of a storage device spin-up control system of controlling spin-up of a plurality of storage devices according to another embodiment of the present general inventive concept, wherein a manual mode switching unit is further included; 
         FIG. 13  is a block diagram of a storage device spin-up control system of controlling spin-up of a plurality of storage devices according to another embodiment of the present general inventive concept, wherein an automatic mode switching unit and a manual mode switching unit are further included; 
         FIG. 14  is a flowchart of a storage device spin-up control method according to an embodiment of the present general inventive concept; 
         FIG. 15  is a flowchart of a storage device spin-up control method of controlling spin-up of a plurality of storage devices according to another embodiment of the present general inventive concept; 
         FIG. 16  illustrates a storage device spin-up control system according to an embodiment of the present general inventive concept; and 
         FIG. 17  illustrates a computing device including a data storage device control unit according to an embodiment of the present general inventive concept. 
     
    
    
     DETAILED DESCRIPTION OF THE EMBODIMENTS 
     Reference will now be made in detail to the embodiments of the present general inventive concept, examples of which are illustrated in the accompanying drawings, wherein like reference numerals refer to the like elements throughout. The embodiments are described below in order to explain the present general inventive concept by referring to the figures. 
       FIGS. 1 and 2  are block diagrams of a storage device spin-up control system  1  according to an embodiment of the present general inventive concept. 
     Referring to  FIG. 1 , the storage device spin-up control system  1  according to an embodiment of the present general inventive concept includes a storage device  100 , an interface  200 , and a host  300 . The interface  200  links the storage device  100  and the host  300 . The storage device  100  may be a hard disk drive. The interface  200  may be any point or terminal connecting the host  300  to the storage device  100 , particularly along a power-supply path. The host  300  may include any type of host device, including a personal computer or terminal, a server, a functional component within a personal computer or server, a stand-alone device, or any other type of host device. 
     In the storage device spin-up control system  1 , the host  300  controls a spin-up mode of the storage device  100  based on the level of a signal output from a power connector of the interface  200 . 
     In particular, the storage device spin-up control system  1  determines whether to spin-up the storage device  100  in a normal current mode or to spin up the storage device  100  in a low current mode in which current level therein is lower than current level in the normal current mode according to the level of the signal output from the power connector of the interface  200 . 
     Referring to  FIG. 2 , the power connector of the interface  200  may be a power connector  210 . The host  300  includes a power supply unit  310 , a current control unit  320 , a power connector signal level detection unit  330 , and a light-emitting diode (LED) driver unit  340 . 
     The interface  200  may be a standard Advanced Technology Attachment (ATA) interface. ATA interfaces are standard interfaces to link storage devices such as personal computers (PCs), hard disks, and CD-ROM drives. 
     Alternatively, the interface  200  may be a Serial Advanced Technology Attachment (SATA) interface. SATA interfaces are computer buses designed to transfer data between storage devices and hosts, such as between the storage device  100  and the host  300 , and particularly, are interfaces using serial encoding to increase data transfer rate. 
     The power connector  210  in the interface  200  may be a power pin  11 , that is, one of power connectors used in an SATA interface. An SATA interface includes a plurality of power connectors. In general, the power pin  11  is used for staggered spin-up. However, in an embodiment of the present general inventive concept, the power pin  11  may be used to control current supplied from the host  300  to the storage device  100 . 
     The power supply unit  310  supplies power to the storage device  100  via the power connector  210  of the interface  200  to spin-up the storage device  100 . 
     The power connector signal level detection unit  330  detects the level of the signal output from the power connector  210  of the interface  200  and outputs a corresponding signal. 
     The current control unit  320  controls the spin-up mode of the storage device  100  based on the level of the signal output from the power connector signal level detection unit  330 . In particular, the current control unit  320  spins up the storage device  100  in the normal current mode if the signal output from the power connector level detection unit  330  is at a first logic level, or spins up the storage device  100  in the low current mode if the signal output from the power connector level detection unit  330  is at a second logic level. 
     When the level of the signal output from the power connector  210  is at the first logic level, the level of the signal may be logic low. When the level of the signal output from the power connector  210  is at the second logic level, the level of the signal may be logic high. 
     The LED driver unit  340  indicates that the storage device  100  is in an active state when the storage device  100  has been successfully spun up using the power supplied from the host  300  and is ready for operation. 
       FIG. 3  is a block diagram of the power connector signal level detection unit  330  of the host  300  in  FIG. 2 , according to an embodiment of the present general inventive concept. 
     The power connector signal level detection unit  330  includes a first detection unit  331 , a second detection unit  332 , a comparison unit  333 , and an output unit  334 . 
     The first detection unit  331  detects a maximum current that can be supplied from the host  300  to spin up the storage device  100 . The second detection unit  332  detects a threshold current required for the storage device  100  to spin up. The comparison unit  333  compares the maximum current detected by the first detection unit  331  and the threshold current detected by the second detection unit  332 . The output unit  334  outputs a signal corresponding to the level of the signal of the power connector  210  at a first logic level if the maximum current is greater than the threshold current and outputs a signal corresponding to the level of the signal of the power connector  210  at a second logic level if the maximum current is less than the threshold current. 
     Referring back to  FIG. 2 , the current control unit  320  spins up the storage device  100  in the normal current mode if the signal output from the output unit  334  of the power connector level detection unit  330  is at the first logic level, and spins up the storage device  100  in the low current mode if the signal output from the output unit  334  of the power connector level detection unit  330  is at the second logic level. 
       FIG. 5A  is a graph of current supplied to the storage device  100  by the host  300  with respect to time when the maximum current is greater than the threshold current.  FIG. 5B  is a graph of current supplied to the storage device  100  by the host  300  with respect to time when the maximum current is less than the threshold current. 
     The storage device  100  may be successfully spun up when the storage device  100  receives a spin-up current greater than or equal to a threshold current I th  from the host  300 . When a maximum current I max  that can be supplied to the storage device  100  by the host  300  is less than the threshold current I th , the storage device  100  may fail to spin up. 
     When the maximum current I max  is greater than the threshold current I th , as illustrated in  FIG. 5A , the storage device  100  may be successfully spun up. In this case, the storage device  100  is spun up in the normal current mode. Once the storage device  100  has been successfully spun up, the host  300  continuously supplies a spin-up current I sp  to the storage device  100  in order to maintain the storage device  100  in the spun up state. 
     However, when the maximum current I max  is less than the threshold current I th , as illustrated by a plot P of  FIG. 5B , the storage  100  may fail to spin up. In this case, the storage device  100  may be spun up in the low current mode, as in a plot Q of  FIG. 5B . 
     Spinning up the storage device  100  in the low current mode implies controlling the threshold current I th  of the storage device  100  to be less than the maximum current I max  supplied from the host  300 . 
     Comparing the plots P and Q, a threshold current I thl  in the plot Q is less than the threshold current I th  in the plot P. In addition, a time t 2  at which the storage device  100  reaches the threshold current I thl  in the plot Q is greater than a time t 1  at which the storage device  100  reaches the threshold current I th  in the plot P. 
     In other words, in the storage device spin-up control system  1  according to an embodiment of the present general inventive concept, when the threshold current I th  of the storage device  100  is greater than the maximum current I max , the storage device  100  may not be successful in spinning up in the normal current mode, and thus the storage device  100  is controlled to spin up in the low current mode, such as in the case of the plot Q. The low-current mode may take longer to achieve an operating spin-up velocity, but it allows the storage device  100  to operate below the threshold current value I th . 
       FIG. 4A  is a timing diagram illustrating the level of a signal output from a power connector of an interface.  FIG. 4B  is a timing diagram illustrating the level of a signal output from the power connector  210  of the interface  200  when spin-up current is controlled by the storage device spin-up control system of  FIGS. 1 and 2 . 
     Referring to  FIG. 4A , the power connector  210  is neither used in a link interval in which the storage device  100  and the host  300  are linked nor in a spin-up interval in which the storage device  100  is to be spun up, but is used in an LED blinking interval in which it may be indicated that the storage device  100  is in an active state. 
     However, referring to  FIG. 4B , unlike the case of  FIG. 4A , the power connector  210  is used in both the link interval in which the storage device  100  and the host  300  are linked, and the spin-up interval in which the storage device  100  is to be spun up, in order to control the spin-up current of the storage device  100 . 
     The storage device spin-up control system  1  according to an embodiment of the present general inventive concept spins up the storage device  100  in the low current mode when the level of the signal output from the power connector  210  in the link interval and in the spin-up interval is output as logic high. 
     The storage device spin-up control system  1  according to an embodiment of the present general inventive concept spins up the storage device  100  in the normal current mode when the signal output from the power connector  210  is at a first logic level after the storage device  100  and the host  300  are linked, and spins up the storage device  100  in the low current mode when the signal output from the power connector  210  is at a second logic level after the storage device  100  and the host  300  are linked. The first logic level may be logic low, as illustrated in  FIG. 4A . The second logic level may be logic high, as illustrated in  FIG. 4B . 
     In other words, if signal output from the power connector  210  indicates that the host  300  may operate above a current threshold I th , the output unit  334  of the power connector signal detection unit  330  may output a logic low signal during link and spin-up states, as illustrated in  FIG. 4A . This may cause the current control unit  320  to output a spin-up signal according to a high-current, or normal-current mode, As illustrated in  FIG. 5A . On the other hand, if signal output from the power connector  210  indicates that the host  300  may operate only below a current threshold I th , the output unit  334  of the power connector signal detection unit  330  may output a logic high signal during link and spin-up states, as illustrated in  FIG. 4B . This may cause the current control unit  320  to output a spin-up signal according to a low-current mode, as indicated by curve Q of  FIG. 5B . 
       FIG. 6  is a block diagram of a storage device spin-up control system  2  according to another embodiment of the present general inventive concept, wherein an automatic mode switching unit  350  is further included. 
     Referring to  FIG. 6 , in the storage device spin-up control system  2  according to an embodiment, a host  300  includes a power supply unit  310 , a current control unit  320 , a power connector signal level detection unit  330 , an LED driver unit  340 , and the automatic mode switching unit  350 . 
     In the storage device spin-up control system  1  illustrated in  FIG. 3 , the power control unit  320  controls current supplied to the storage device  100  from the power supply unit  310  of the host  300  based on the level of a signal output from the output unit  334  of the power connector signal level detection unit  330 . 
     In the embodiment illustrated in  FIG. 6 , the automatic mode switching unit  350  is further included in the host  300 , unlike the previous embodiment shown in  FIG. 2 . The automatic mode switching unit  350  performs controlling in such a way that the current control unit  320  and the power connector signal level detection unit  330  are not operated in an initial spin-up stage of the storage unit  100  and current is supplied from the power supply unit  310  to the storage unit  100 . 
     The automatic mode switching unit  350  determines whether the storage device  100  has been successfully spun up by using the current supplied from the power supply unit  310  of the host  300 . The automatic mode switching unit  350  performs controlling in such a way that the current control unit  320  and the power connector signal level detection unit  330  are not operated if the spinning up of the storage device  100  is successful and are operated if the storage device  100  fails to spin up. A method of controlling the spin-up mode of the storage device  100  by using the current control unit  320  and the power connector signal level detection unit  330  when the storage device  100  fails to spin up is the same as described above with reference to  FIGS. 2 and 3 . 
       FIG. 7  is a block diagram of a storage device spin-up control system  3  according to another embodiment of the present general inventive concept, wherein a manual mode switching unit  360  is further included. 
     The manual mode switching unit  360  is located outside the host  300 . In the storage device spin-up control system  3  according to the embodiment illustrated in  FIG. 7 , the manual mode switching unit  360  is used to enable the host  300  to control the spin-up mode of the storage device  100  exclusively when the manual mode switching unit  360  is selected by a user. 
     In particular, when the manual mode switching unit  360  is not selected by the user, the host  300  spins up the storage device  100  in the normal current mode. When the manual mode switching unit  360  is selected by the user, the host  300  spins up the storage device  100  in the low current mode. 
     The manual mode switching unit  360  may be an external switch located outside the host  300 , for example. 
       FIG. 8  is a block diagram of a storage device spin-up control system  4  according to another embodiment of the present general inventive concept, wherein an automatic mode switching unit  350  and a manual mode switching unit  360  are both connected to the power connector  210 . 
     The storage device spin-up control system  4  according to an embodiment of the present general inventive concept includes both the automatic mode switching unit  350 , which is located in the host  300 , and the manual mode switching unit  360 , which may be located outside the host  300 . 
     The automatic mode switching unit  350  and the manual mode switching unit  360  are respectively described above with reference to  FIGS. 6 and 7 , and thus a detailed description thereof will not be provided here. 
       FIG. 9  is a block diagram of a storage device spin-up control system  5  to control spin-up of a plurality of storage devices according to another embodiment of the present general inventive concept. 
     Referring to  FIG. 9 , the storage device spin-up control system  5  includes a storage device unit  110  including N storage devices, wherein N is a natural number of 2 or greater, an interface  200  including a power connector  210 , and a host  300 . The host  300  controls spin-up mode of each of the N storage devices based on the level of a signal output from the power connector  210  of the interface  200 . 
     The host  300  includes a power supply unit  310 , a current control unit  320 , a power connector signal level detection unit  330 , an LED driver unit  340 , and a staggered spin-up (SSU) control unit  370 . 
     The SSU control unit  370  controls sequential spinning up of the N storage devices. For example, the SSU control unit  370  may control the spinning up of the storage devices in such a way that a 2 nd  storage device is spun up a predetermined amount of time after a 1 st  storage device has been spun up. Likewise, a 3 rd  storage device is spun up a predetermined amount of time after the 2 nd  storage device has been spun up. 
     The power connector signal level detection unit  330  detects the level of the signal output from the power connector  210  and outputs a corresponding signal. 
     The power connector signal level detection unit  330  has the same structure as illustrated in  FIG. 3 . 
     In particular, referring back to  FIG. 3 , the first detection unit  331  detects a maximum current that can be supplied from the host  300  to spin up the N storage devices. The second detection unit  332  detects a threshold current required for an n th  storage device to spin up, wherein n is a natural number from 1 to N, and the n th  storage device being one of the N storage devices. 
     The comparison unit  333  compares the maximum current detected by the first detection unit  331  and the threshold current required for the n th  storage device to spin up, which is detected by the second detection unit  332 . 
     The output unit  334  outputs a signal corresponding to the level of the signal of the power connector  210  at a first logic level if the maximum current is greater than the threshold current required for the n th  storage device to spin up and outputs a signal corresponding to the level of the signal of the power connector  210  at a second logic level if the maximum current is less than the threshold current required for n th  storage device to spin up. 
     The current control unit  320  controls spin-up mode of the n th  storage device based on the level of the signal output from the output unit  334  of the power connector signal level detection unit  330 . 
     In particular, the current control unit  320  spins up the n th  storage device in the normal current mode if the level of the signal output from the power connector level detection unit  330  is at the first logic level, and spins up the n th  storage device in the low current mode if the level of the signal output from the power connector level detection unit  330  is at the second logic level. 
     In the storage device spin-up control system  5 , the interface  200  may be an SATA interface. The power connector  210  may be a power pin  11 , that is, one of the power connectors used in an SATA interface. 
       FIG. 10A  is a timing diagram illustrating the level of a signal output from a power connector of an interface.  FIG. 10B  is a timing diagram illustrating the level of a signal output from the power connector  210  of the interface  200  when spin-up current is controlled to spin up the plurality of storage devices by the storage device spin-up control system of  FIG. 9 . 
     Referring to  FIG. 10A , the signal output from the power connector  210  is logic high in an SSU control interval. Then, when the signal output from the power connector  210  becomes logic low, the n th  storage device and the host  300  are linked. The power connector  210  is not operated in a spin-up interval in which the n th  storage device is to be spun up, but is used in an LED blinking interval in which it may be indicated that the nth storage device is in an active state. 
     Referring to  FIG. 10B , unlike the case of  FIG. 10A , the power connector  210  is used in an initial stage of the spun-up interval in which the n th  storage device is to be spun up, in order to control spin-up current for the n th  storage device. 
     The storage device spin-up control system  1  to control spin-up of a plurality of storage devices according to an embodiment of the present general inventive concept spins up the n th  storage device  100  in the low current mode when the level of the signal output from the power connector  210  in the initial stage of the spin-up interval is output as logic high. 
     The storage device spin-up control system  5  to control spin-up of a plurality of storage devices according to an embodiment of the present general inventive concept spins up the n th  storage device  100  in the normal current mode when the level of the signal output from the power connector  210  is at a first logic level after the n th  storage device and the host  300  are linked and spins up the n th  storage device in the low current mode when the level of the signal output from the power connector  210  is at a second logic level after the n th  storage device and the host  300  are linked. The first logic level may be logic low, as illustrated in  FIG. 10A . The second logic level may be logic high, as illustrated in  FIG. 10B . 
       FIG. 11  is a block diagram of a storage device spin-up control system  6  to control spin-up of a plurality of storage devices, according to another embodiment of the present general inventive concept, wherein an automatic mode switching unit  350  is further included in a host  300 . 
     Referring to  FIG. 11 , the host  300  includes a power supply unit  310 , a current control unit  320 , a power connector signal level detection unit  330 , an LED driver unit  340 , an SSU control unit  370 , and the automatic mode switching unit  350 . 
     As described in the previous embodiment with reference to  FIG. 9 , the power control unit  320  controls current supplied to the n th  storage device from the power supply unit  310  of the host  300  based on the level of a signal output from an output unit  334  (see  FIG. 3 ) of the power connector signal level detection unit  330 . 
     In an embodiment according to  FIG. 11 , the automatic mode switching unit  350  is further included in the host  300 , unlike the previous embodiment described with reference to  FIG. 9 . The automatic mode switching unit  350  performs controlling in such a way that the current control unit  320  and the power connector signal level detection unit  330  are not operated in an initial spin-up stage of the n th  storage device and current is supplied from the power supply unit  310  to the n th  storage device in the initial spin-up stage. 
     The automatic mode switching unit  350  determines whether the n th  storage device has been successfully spun up by using the current supplied from the power supply unit  310  of the host  300 . The automatic mode switching unit  350  performs controlling in such a way that the current control unit  320  and the power connector signal level detection unit  330  are not operated if the storage device  100  is successfully spun up, and are operated if the storage device  100  fails to spin up. A method of controlling the spin-up mode of the n th  storage device by using the current control unit  320  and the power connector signal level detection unit  330  when the storage device  100  fails to spin up is the same as described above with reference to  FIG. 9 . 
       FIG. 12  is a block diagram of a storage device spin-up control system  7  to control spin-up of a plurality of storage devices, according to another embodiment of the present general inventive concept, wherein a manual mode switching unit  360  is further included. 
     The manual mode switching unit  360  is located outside the host  300 . In the storage device spin-up control system  7  according to an embodiment, the manual mode switching unit  360  is used to enable the host  300  to control the spin-up mode of a storage device unit  110  exclusively when the manual mode switching unit  360  is selected by a user. In particular, when the manual mode switching unit  360  is not selected by the user, the host  300  spins up the n th  storage device in a normal current mode. When the manual mode switching unit  360  is selected by the user, the host  300  spins up the n th  storage device in a low current mode. 
     The manual mode switching unit  360  may be an external switch located outside the host  300 . 
       FIG. 13  is a block diagram of a storage device spin-up control system  8  to control spin-up of a plurality of storage devices according to another embodiment of the present general inventive concept, wherein an automatic mode switching unit  350  and a manual mode switching unit  360  are both included. 
     The storage device spin-up control system  8  as illustrated in  FIG. 13  includes both the automatic mode switching unit  350 , which is located in the host  300 , and the manual mode switching unit  360 , which is located outside the host  300 . 
     The automatic mode switching unit  350  and the manual mode switching unit  360  are respectively described above with reference to  FIGS. 11 and 12 , and thus a detailed description thereof will not be provided here. 
       FIG. 14  is a flowchart of a storage device spin-up control method according to an embodiment of the present general inventive concept. 
     With reference to the storage device spin-up control systems  1  to  4  of  FIGS. 2 ,  6 ,  7  and  8 , in order to supply spin-up current from the host  300  to the storage device  100 , the host  300  and the storage device  100  are linked via the interface  200  (operation S 1 ). 
     The power connector signal level detection unit  330  in the host  300  detects the level of a signal output from the power connector  210  of the interface  200  linking the host  300  and the storage device  100  and outputs a corresponding signal (operation S 2 ). 
     Operation S 2  involves detecting a maximum current that can be supplied from the host  300  to spin up the storage device  100 , detecting a threshold current required for the storage device  100  to spin up, comparing the maximum current and the threshold current, and outputting a signal corresponding to the level of the signal of the power connector at a first logic level if the maximum current is greater than the threshold current and outputting a signal corresponding to the level of the signal of the power connector at a second logic level if the maximum current is less than the threshold current. 
     The current control unit  320  in the host  300  controls a spin-up mode of the storage device  100  based on the detected level of the signal output from the power connector  210 . 
     In operation S 3  of controlling a spin-up mode of the storage device  100 , the host  300  spins up the storage device  100  in a normal current mode if the level of the signal output from the power connector  210  is at the first logic level, and spins up the storage device  100  in a low current mode if the level of the signal output from the power connector  210  is the second logic level. 
     In an embodiment, the first logic level may be logic low, and the second logic level may be logic high. 
     The LED driver unit  340  in the host  300  blinks an LED when the storage device  100  has been successfully spun up using the power supplied from the host  300  and when the storage device  100  is ready for operation. 
       FIG. 15  is a flowchart of a storage device spin-up control method of controlling spin-up of a plurality of storage devices, according to another embodiment of the present general inventive concept. 
     In the storage device spin-up control method according to  FIG. 15 , spin-up modes of N storage devices, where N is a natural number of 2 or greater, are sequentially controlled based on the level of a signal output from the power connector  210  of the interface  200 . 
     The SSU control unit  370  in the host  300  controls the N storage devices to be sequentially spun up (operation S 11 ). In order to supply a spin-up current from the host  300  to a n th  storage device, the host  300  and the n th  storage device, where n is a natural number from 1 to N, are linked via the interface  200  (operation S 12 ). 
     The power connector signal level detection unit  330  in the host  300  detects the level of a signal output from the power connector  210  of the interface  200  and outputs a corresponding signal (operation S 13 ). 
     Operation S 2  involves detecting a maximum current that can be supplied from the host  300  to spin up the N storage devices, detecting a threshold current required for the n th  storage device to spin up, comparing the maximum current and the threshold current, and outputting a signal corresponding to the level of the signal output from the power connector at a first logic level if the maximum current is greater than the threshold current required for the n th  storage device to spin up and outputting a signal corresponding to the level of the signal of the power connector at a second logic level if the maximum current is less than the threshold current required for the n th  storage device to spin up. 
     The current control unit  320  in the host  300  controls a spin-up mode of the n th  storage device based on the detected level of the signal output from the power connector  210  (operation S 14 ). 
     In operation S 14  of controlling a spin-up mode of the n th  storage device, the host  300  spins up the n th  storage device in a normal current mode if the level of the signal output from the power connector  210  is at the first logic level, and spins up the n th  storage device in a low current mode if the level of the signal of the power connector  210  is at the second logic level. 
     The first logic level may be logic low and the second logic level may be logic high, for example. 
     The LED driver unit  340  in the host  300  blinks an LED when the n th  storage device has been successfully spun up by using the power supplied from the host  300  and is ready for operation. 
       FIG. 16  illustrates an example of a storage-device spin-up control system  9  according to an embodiment of the present general inventive concept. The system  9  may include the storage device  100  connected via a cable or other connector  202  to a host device  300 . The cable  202  may be connected to the host device  300  via an interface  200 , for example. As illustrated in  FIG. 16 , the storage device  100  and host device  300  may be separate devices having separate frames or covers. The host device  300  may include the power supply unit  310 , current control unit  320 , power connector signal detection unit  330 , and LED driver unit  340  illustrated in  FIG. 2 . The LED driver unit  340  may drive an LED  341  to illuminate when the host device  300  accesses or controls the storage unit  100 , for example. 
     The host device  300  may be a personal computer or terminal, and it may be directly connected to a display  302  and a user interface  304  to allow a user to operate the host device  300 . The host device  300  may be connected via a wired or wireless network  500  to a user terminal or PC  510  or another host device  520  or external device to control the host device  300 . 
       FIG. 17  illustrates a computing device  400  according to an embodiment of the present general inventive concept in which the storage device, or data storage device,  100  and the host device  300  are part of the computing device  400 . The computing device  400  may include a display  402  to display data, a user interface  404  to allow a user to interact with the display  402  to control the computing device  400 , and an external device interface  406  to transmit and/or receive data to/from external devices. The display  402  may be a CRT monitor, an LED display, an LCD display, or any other type of display. The user interface  404  may be a keyboard, mouse, keypad, touch-screen, or any other type of user interface. The external device interface  406  may include wired ports and/or a wireless transceiver. 
     The data storage device  100  may be a hard disk drive, for example. A data storage device control unit  408  may control power supplied to the data storage device. The data storage device control unit  408  may correspond to the host unit  300  of  FIG. 2 , for example. A controller  410  may control operation of the computing device  400  including the data storage device  100  and the data storage device control unit  408 . The controller  410  may include one or more processors, memory, and logic to control operation of the computing device  400 . 
     The functional units of the host  300  may also be included in a same device as the data storage device  100 . In other words, a single data storage device  100  may include a hard disk drive, a power supply unit, a current control unit, a power connector signal detection unit, and an LED driver unit. The combination of the hard disk drive and the host may be called a data storage device and may be included within a single frame, case, or cover. Operation of the combined storage device  100  and host  300  may be similar to the operation described above, with respect to  FIGS. 1-15 . In such a case, the power connector  210  may be a terminal of a cord or cable, a location on a wire or wiring on a printed circuit board, or any other point along an electrical path of the power supplied from the host  300  to the storage device  100 . 
     As described above, according to the one or more of the above embodiments of the present general inventive concept, a spin-up mode of a storage device is selectively controlled based on the level of a signal output from a power connector of an interface connecting a host and the storage device. Thus, spin-up failure of the storage device caused due to insufficient power from the host may be prevented. 
     While the present general inventive concept has been particularly shown and described with reference to exemplary embodiments thereof, it will be understood by those of ordinary skill in the art that various changes in form and details may be made therein without departing from the spirit and scope of the present general inventive concept as defined by the following claims.