Patent Publication Number: US-2005125706-A1

Title: System and method for starting up plural electronic devices in an orderly manner

Description:
BACKGROUND OF THE INVENTION  
      1. Field of the Invention  
      The present invention relates to a system and method for starting up plural electronic devices, and particularly to a system and method for starting up plural disk drives on respective backboards in an orderly manner.  
      2. Description of Related Art  
      Generally, a computer system stores digital data in a storage device thereof. When the available capacity of the storage device is exhausted, plural storage devices can be connected to the computer system in order to enlarge the total available capacity. The storage devices can be disk drives or other kinds of storage devices known in the art.  
      In a typical application, a disk drive that has a driving electrical current of 2 amperes is electrically connected to a power source. When the power source is turned on, an electrical current output from the power source is transmitted to the disk drive to start up it. An initial instantaneous peak-value electrical current of the power source is equivalent to the driving electrical current of 2 amperes. Thereafter, a working electrical current of the disk drive decreases to an average value of less than 2 amperes. When few disk drives are connected to the power source, a total instantaneous peak-value electrical current is relatively low and can be easily supplied by the power source. However, when numerous disk drives are connected to the power source, the total instantaneous peak-value electrical current is correspondingly high. For example, if eight disk drives are connected to the power source, the total instantaneous peak-value electrical current required is 16 amperes if the eight disk drives are started up simultaneously. Ordinary power sources cannot supply such a strong electrical current, and a special power source must be employed in order to solve the problem. However, the purchase and running costs of such a power source are inevitably high.  
      Consequently, a system and method for starting up plural electronic devices in an orderly manner are needed, so as to decrease the instantaneous peak-value electrical current normally required when the plural electronic devices are start up simultaneously.  
     SUMMARY OF THE INVENTION  
      A first object of the present invention is to provide a system for starting up plural electronic devices in an orderly manner.  
      A second object of the present invention is to provide a method for starting up plural electronic devices in an orderly manner.  
      In order to fulfill the above-mentioned first object, the present invention provides a system for starting up plural electronic devices in an orderly manner. The system includes a power source and a plurality of backboards electrically connected to it. Each of the backboards includes: a controller for outputting a low voltage signal; a plurality of jumpers electrically connected to the controller and to ground in parallel; a switch electrically connected to the controller for controlling electrical current; and an electronic device electrically connected to the switch. The switch on each of the backboards is electrically connected to the power source. The controller on each of the backboards configures a time delay of the low voltage signal to be output, according to a combination of the states of the jumpers on the backboard. Each of the jumpers on each of the backboards can be in either a disconnected state or a connected state. The electronic devices can be any of various kinds used in a particular application, and may for example include one or more disk drives.  
      In order to fulfill the above-mentioned second object, the present invention provides a method for starting up plural electronic devices in an orderly manner. The method includes the following steps: (a) according to a first combination of states of jumpers on a first backboard, at the moment a first time delay elapses, outputting a low voltage signal to a first switch on a first backboard to activate the first switch to be “open,” and starting up a first electronic device on the first backboard; (b) according to a subsequent combination of states of jumpers on a subsequent backboard, at the moment a subsequent time delay elapses, outputting a low voltage signal to a subsequent switch on the subsequent backboard to activate the subsequent switch to be “open,” and starting up a subsequent electronic device on the subsequent backboard; and (c) repeating step (b) for each of any further backboards and respective jumpers, switches and electronic devices thereof, at the moment each of any respective subsequent time delays elapses. The method further includes the step of outputting a high voltage signal to the switch on each of the backboards, for ensuring that the switches are each in a “closed” state before step (a).  
      Other objects, advantages and novel features of the present invention will become more apparent from the following detailed description when taken in conjunction with the accompanying drawings. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       FIG. 1  is a block diagram of hardware infrastructure of an exemplary embodiment of the system according to the present invention;  
       FIG. 2  is a time/voltage diagram of operation of the system of the  FIG. 1 ; and  
       FIG. 3  is a flow chart of an exemplary method for starting up plural disk drives in an orderly manner according to the present invention. 
    
    
     DETAILED DESCRIPTION OF THE INVENTION  
       FIG. 1  is a block diagram of hardware infrastructure of the exemplary embodiment of the system for starting up plural electronic devices in an orderly manner (hereinafter, “the system”) of the present invention. In the exemplary embodiment, the system includes four backboards  1 ,  2 ,  3 ,  4  and a power source  5 . The backboards  1 ,  2 ,  3 ,  4  are electrically connected to the power source  5 . Each of the backboards  1 ,  2 ,  3 ,  4  includes a controller, two jumpers, a switch and a disk drive.  
      The backboard  1  includes a controller  11 , two jumpers  111  and  112 , a switch  12 , and a disk drive  13 . The controller  11  is used for outputting a low voltage signal. The jumpers  111  and  112  are electrically connected to the controller  11  and to ground in parallel. The controller  11  configures a first time delay of the low voltage signal to be output, according to the states of the jumpers  111  and  112 . The switch  12  is electrically connected to the controller  11  and the power source  5  for controlling electrical current of the disk drive  13 . The disk drive  13  is electrically connected to the switch  12 . The state of each jumper  111  and  112  on the backboard  1  is “disconnected.” 
      The backboard  2  includes a controller  21 , two jumpers  211  and  212 , a switch  22 , and a disk drive  23 . The controller  21  is used for outputting a low voltage signal. The jumpers  211  and  212  are electrically connected to the controller  21  and to ground in parallel. The controller  21  configures a second time delay of the low voltage signal to be output, according to the states of the jumpers  211  and  212 . The switch  22  is electrically connected to the controller  21  and the power source  5  for controlling electrical current of the disk drive  23 . The disk drive  23  is electrically connected to the switch  22 . The state of the jumper  211  on the backboard  2  is “disconnected,” and the state of the jumper  212  on the backboard  2  is “connected.” 
      The backboard  3  includes a controller  31 , two jumpers  311  and  312 , a switch  32 , and a disk drive  33 . The controller  31  is used for outputting a low voltage signal. The jumpers  311  and  312  are electrically connected to the controller  31  and to ground in parallel. The controller  31  configures a third time delay of the low voltage signal to be output, according to the states of the jumpers  311  and  312 . The switch  32  is electrically connected to the controller  31  and the power source  5  for controlling electrical current of the disk drive  33 . The disk drive  33  is electrically connected to the switch  32 . The state of the jumper  311  on the backboard  3  is “connected,” and the state of the jumper  312  on the backboard  3  is “disconnected.” 
      The backboard  4  includes a controller  41 , two jumpers  411  and  412 , a switch  42 , and a disk drive  43 . The controller  41  is used for outputting a low voltage signal. The jumpers  411  and  412  are electrically connected to the controller  41  and to ground in parallel. The controller  41  configures a fourth time delay of the low voltage signal to be output, according to the states of the jumpers  411  and  412 . The switch  42  is electrically connected to the controller  41  and the power source  5  for controlling electrical current of the disk drive  43 . The disk drive  43  is electrically connected to the switch  42 . The state of each jumper  411  and  412  on the backboard  4  is “connected.” 
      As described above, the system of the exemplary embodiment includes only four disk drives  1 ,  2 ,  3 ,  4 . In other embodiments, the system can include more disk drives according to particular requirements. In such cases, the system has more backboards. For example, the system may have eight backboards. However, the more disk drives there are, the longer the time needed for starting up the disk drives in an orderly manner. Generally, the system must start up all disk drives within a given time, which limits the maximum number of disk drives. Additionally, the power source can only supply electrical power to a limited number of disk drives. That is, the power source is also a factor which limits the maximum number of disk drives.  
       FIG. 2  is a time/voltage diagram of operation of the system. A “disconnected” state and a “connected” state of each of the jumpers on each of the backboards are represented by two opposite signals. In the exemplary embodiment of the invention, a “disconnected” state of each jumper is represented by a signal “0,” and a “connected” state of each jumper is represented by a signal “1.” Therefore a combination of the states of the two jumpers on each of the backboards is represented by a two-digit binary sequence. For example, if both jumpers on the backboard are “disconnected,” the combination of the states of the jumpers is represented as “00.” If both jumpers on the backboard are “connected,” the combination of the states of the jumpers is represented as “11.” 
      The state of the jumpers  111  and  112  on the backboard  1  are both “disconnected,” therefore the combination of the states of the jumpers  111  and  112  is represented as “00.” This determines the first time delay of starting up the disk drive  13 , which is equivalent to one predefined time unit. The state of the jumper  211  on the backboard  2  is “disconnected,” and the state of the jumper  212  on the backboard  2  is “connected,” therefore the combination of the states of the jumpers  211  and  212  is represented as “01.” This determines the second time delay of starting up the disk drive  23 , which is equivalent to two time units. The state of the jumper  311  on the backboard  3  is “connected,” and the state of the jumper  312  on the backboard  3  is “disconnected,” therefore the combination of the states of the jumpers  311  and  312  is represented as “10.” This determines the third time delay of starting up the disk drive  33 , which is equivalent to three time units. The states of the jumpers  411  and  412  on the backboard  4  are both “connected,” therefore the combination of the states of the jumpers  411  and  412  is represented as “11.” This determines the fourth time delay of starting up the disk drive  43 , which is equivalent to four time units.  
       FIG. 3  is a flow chart of the exemplary method for starting up plural disk drives in an orderly manner according to the present invention. In step  100 , when the power source  5  is turned on, high voltage signals output from the controllers  11 ,  21 ,  31 , and  41  are transmitted to the switches  12 ,  22 ,  32 , and  42  respectively. The high voltage signals set the switches  12 ,  22 ,  32 , and  42  as each being in a “closed” state. Accordingly, no electrical current is input to the disk drives  13 ,  23 ,  33 , and  43  via the switches  12 ,  22 ,  32 , and  42 .  
      In step  101 , at the moment the first time delay elapses, the controller  11  outputs a low voltage signal according to the combination of the states of the jumpers  111  and  112 . The low voltage signal is transmitted to the switch  12  to activate the switch  12  to be “open.” As a result, an electrical current from the power source  5  is transmitted to the disk drive  13  via the switch  12  to start up the disk drive  13 . The switches  22 ,  32  and  42  are each still in the “closed” state.  
      In step  102 , at the moment the second time delay elapses, the controller  21  outputs a low voltage signal according to the combination of the states of the jumpers  211  and  212 . The low voltage signal is transmitted to the switch  22  to activate the switch  22  to be “open.” As a result, the electrical current from the power source  5  is transmitted to the disk drive  23  via the switch  22  to start up the disk drive  23 . The switches  32  and  42  are each still in the “closed” state.  
      In step  103 , at the moment the third time delay elapses, the controller  31  outputs a low voltage signal according to the combination of the states of the jumpers  311  and  312 . The low voltage signal is transmitted to the switch  32  to activate the switch  32  to be “open.” As a result, the electrical current from the power source  5  is transmitted to the disk drive  33  via the switch  32  to start up the disk drive  33 . The switch  42  is still in the “closed” state.  
      In step  104 , at the moment the fourth time delay elapses, the controller  41  outputs a low voltage signal according to the combination of the states of the jumpers  411  and  412 . The low voltage signal is transmitted to the switch  42  to activate the switch  42  to be “open.” As a result, the electrical current from the power source  5  is transmitted to the disk drive  43  via the switch  42  to start up the disk drive  43 .  
      Further, while an exemplary embodiment and method of the present invention have been described above, it should be understood that they have been presented by way of example only and not by way of limitation. Thus the breadth and scope of the present invention should not be limited by the above-described exemplary embodiment and method, but should be defined only in accordance with the following claims and their equivalents.