Abstract:
A control method executed by an information processing system that includes a plurality of electronic devices arranged side by side in a single direction in a common housing and having temperature sensors and includes a managing device coupled to the plurality of electronic devices, the control method includes activating an electronic device among the plurality of electronic devices based on a predetermined order; receiving temperature information from the temperature sensors included in the plurality of electronic devices, the temperature information indicating temperatures of the plurality of electronic devices that are measured when any of the plurality of electronic devices operates and another one or more electronic devices excluding the operating electronic device do not operate; and identifying positions of the plurality of electronic devices arranged in the common housing, based on amounts of changes in temperatures of the plurality of electronic devices calculated using the temperature information.

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
       [0001]    This application is based upon and claims the benefit of priority of the prior Japanese Patent Application No. 2015-092495, filed on Apr. 30, 2015, the entire contents of which are incorporated herein by reference. 
       FIELD 
       [0002]    The embodiments discussed herein are related to a control method, an information processing system, and a storage medium. 
       BACKGROUND 
       [0003]    With the widespread use of data centers and on-premises cloud systems, the number of cases where multiple servers are arranged in each of racks and many servers are managed on a rack basis has been increasing. In such an information processing system, servers are installed in racks upon the shipment from a factory or are installed at a site such as a data center and connected to a network switch through cables. 
         [0004]    However, in order to manage materials and ensure the convenience of maintenance, the IDs of the servers and the like are associated with the positions of the servers and the like in the racks and managed. The IDs are serial numbers of electronic devices such as the servers, MAC addresses used in an administration LAN, or the like and are information specific to each of the electronic devices such as the servers, for example. 
         [0005]    Normally, the association of the IDs of the servers with the positions of the servers in the racks is executed by visually confirming the IDs of the servers and the positions in the racks and entering the IDs and the positions in a management ledger (for example, management software on a computer). However, if the IDs of the servers and the positions in the racks are manually associated, it takes great time and cost. Thus, techniques for automatically associating the IDs of servers with the positions of the servers in the racks have been researched. 
         [0006]    For example, a technique for attaching modules for providing positional information to racks, attaching sensors for reading the positional information from the modules to servers, and automatically associating the servers with the positions of the servers in the racks has been developed. In addition, a technique for identifying servers and the positions of the servers in racks using an intelligent power distribution unit (PDU) has been developed. 
         [0007]    Furthermore, a technique for using a temperature sensor to determine the position of a specific electronic device or the position of a hot spot in a processor has been developed (refer to, for example, Japanese Laid-open Patent Publication No. 7-152442 or Japanese Laid-open Patent Publication No. 2005-346590). 
         [0008]    In the aforementioned technique for automatically associating servers with the positions of the servers in racks, special devices (the modules and the sensors, the intelligent PDU, or the like) are used and thus costly. In addition, a system in which the special devices are not able to be installed exists. Thus, it is desirable to automatically associate electronic devices with information identifying the electronic devices without the special devices. 
       SUMMARY 
       [0009]    According to an aspect of the invention, a control method executed by an information processing system that includes a plurality of electronic devices arranged side by side in a single direction in a common housing and having temperature sensors and includes a managing device coupled to the plurality of electronic devices, the control method includes activating an electronic device among the plurality of electronic devices based on a predetermined order; receiving temperature information from the temperature sensors included in the plurality of electronic devices, the temperature information indicating temperatures of the plurality of electronic devices that are measured when any of the plurality of electronic devices operates and another one or more electronic devices excluding the operating electronic device do not operate; and identifying positions of the plurality of electronic devices arranged in the common housing, based on amounts of changes in temperatures of the plurality of electronic devices calculated using the temperature information. 
         [0010]    The object and advantages of the invention will be realized and attained by means of the elements and combinations particularly pointed out in the claims. 
         [0011]    It is to be understood that both the foregoing general description and the following detailed description are exemplary and explanatory and are not restrictive of the invention, as claimed. 
     
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
         [0012]      FIG. 1  is a schematic diagram illustrating an information processing system according to a first embodiment; 
           [0013]      FIG. 2  is a top view of an operation server; 
           [0014]      FIG. 3  is a schematic diagram illustrating a configuration of a managing device after dedicated software is read; 
           [0015]      FIG. 4  is a first flowchart of a control method to be executed by the information processing system according to the first embodiment; 
           [0016]      FIG. 5  is a second flowchart of the control method to be executed by the information processing system according to the first embodiment; 
           [0017]      FIG. 6  is a third flowchart of the control method to be executed by the information processing system according to the first embodiment; 
           [0018]      FIG. 7  is a diagram illustrating an example of a managed device information table; 
           [0019]      FIG. 8  is a diagram illustrating the managed device information table in which 1 is recorded as a rack position number of an operation server arranged on a top shelf of a rack; 
           [0020]      FIG. 9  is a diagram illustrating the managed device information table in which serial numbers of servers are recorded; 
           [0021]      FIG. 10  is a diagram illustrating an example of a temperature management information table; 
           [0022]      FIG. 11  is a diagram illustrating the temperature management information table when a server with a table identification number 1 operates; 
           [0023]      FIG. 12  is a diagram illustrating the temperature management information table after a sub-process executed for the second time is terminated; 
           [0024]      FIG. 13  is a diagram illustrating an example of a temperature change table; 
           [0025]      FIG. 14  is a diagram illustrating the managed device information table after rack position numbers of all the servers are recorded; 
           [0026]      FIG. 15  is a schematic diagram illustrating an information processing system according to a second embodiment; 
           [0027]      FIG. 16  is a first flowchart of a control method to be executed by the information processing system according to the second embodiment; 
           [0028]      FIG. 17  is a second flowchart of the control method to be executed by the information processing system according to the second embodiment; 
           [0029]      FIG. 18  is a third flowchart of the control method to be executed by the information processing system according to the second embodiment; 
           [0030]      FIG. 19  is a diagram illustrating an example of a managed device information table; 
           [0031]      FIG. 20  is a diagram illustrating the managed device information table in which serial numbers of servers are recorded; 
           [0032]      FIG. 21  is a diagram illustrating an example of a temperature management information table; 
           [0033]      FIG. 22  is a diagram illustrating the temperature management information table when a server with a table identification number 2 operates; 
           [0034]      FIG. 23  is a diagram illustrating the temperature management information table after a sub-process executed for the second time is terminated; 
           [0035]      FIG. 24  is a diagram illustrating an example of a temperature change table; 
           [0036]      FIG. 25  is a diagram illustrating the managed device information table after rack position numbers of all the servers are recorded; 
           [0037]      FIG. 26  is a schematic diagram illustrating an information processing system according to a third embodiment; 
           [0038]      FIG. 27  is a first flowchart of a control method to be executed by the information processing system according to the third embodiment; 
           [0039]      FIG. 28  is a second flowchart of the control method to be executed by the information processing system according to the third embodiment; 
           [0040]      FIG. 29  is a third flowchart of the control method to be executed by the information processing system according to the third embodiment; 
           [0041]      FIG. 30  is a diagram illustrating an example of a managed device information table; 
           [0042]      FIG. 31  is a diagram illustrating the managed device information table in which the serial numbers of servers are recorded; 
           [0043]      FIG. 32  is a diagram illustrating an example of a temperature management information table; 
           [0044]      FIG. 33  is a diagram illustrating the temperature management information table when the server with the table identification number 2 operates; 
           [0045]      FIG. 34  is a diagram illustrating the temperature management information table after a sub-process executed for the second time is terminated; 
           [0046]      FIG. 35  is a diagram illustrating an example of a temperature change table; 
           [0047]      FIG. 36  is a diagram illustrating the managed device information table after rack position numbers of all the servers are recorded; 
           [0048]      FIG. 37  is a schematic diagram illustrating an information processing system according to a fourth embodiment; 
           [0049]      FIG. 38  is a first flowchart of a control method to be executed by the information processing system according to the fourth embodiment; 
           [0050]      FIG. 39  is a second flowchart of the control method to be executed by the information processing system according to the fourth embodiment; 
           [0051]      FIG. 40  is a third flowchart of the control method to be executed by the information processing system according to the fourth embodiment; 
           [0052]      FIG. 41  is a fourth flowchart of the control method to be executed by the information processing system according to the fourth embodiment; 
           [0053]      FIG. 42  is a diagram illustrating a managed device information table; 
           [0054]      FIG. 43  is a diagram illustrating the managed device information table in which 1 is recorded as a rack position number of an operation server arranged on a top shelf of a rack; 
           [0055]      FIG. 44  is a diagram illustrating an example of a temperature management information table; 
           [0056]      FIG. 45  is a diagram illustrating the temperature management information table when the server with the table identification number 2 operates; 
           [0057]      FIG. 46  is a diagram illustrating the temperature management information table after a sub-process executed for the second time is terminated; 
           [0058]      FIG. 47  is a diagram illustrating an example of a temperature change table; 
           [0059]      FIG. 48  is a diagram illustrating the managed device information table after rack position numbers of all electronic devices are recorded; 
           [0060]      FIG. 49  is a schematic diagram illustrating an information processing system according to a fifth embodiment; 
           [0061]      FIG. 50  is a first flowchart of a control method to be executed by the information processing system according to the fifth embodiment; 
           [0062]      FIG. 51  is a second flowchart of the control method to be executed by the information processing system according to the fifth embodiment; 
           [0063]      FIG. 52  is a third flowchart of the control method to be executed by the information processing system according to the fifth embodiment; 
           [0064]      FIG. 53  is a diagram illustrating an example of a managed device information table; 
           [0065]      FIG. 54  is a diagram illustrating the managed device information table in which 1 is recorded as a rack position number of an operation server arranged on the leftmost side of a rack; 
           [0066]      FIG. 55  is a diagram illustrating the managed device information table in which serial numbers of servers are recorded; 
           [0067]      FIG. 56  is a diagram illustrating an example of a temperature management information table; 
           [0068]      FIG. 57  is a diagram illustrating the temperature management information table when the server with the table identification number 1 operates; 
           [0069]      FIG. 58  is a diagram illustrating the temperature management information table after a sub-process executed for the second time is terminated; 
           [0070]      FIG. 59  is a diagram illustrating an example of a temperature change table; and 
           [0071]      FIG. 60  is a diagram illustrating the managed device information table after rack position numbers of all the servers are described. 
       
    
    
     DESCRIPTION OF EMBODIMENTS 
       [0072]    Hereinafter, embodiments are described with reference to the accompanying drawings. 
       First Embodiment 
       [0073]      FIG. 1  is a schematic diagram illustrating an information processing system according to a first embodiment. 
         [0074]    The information processing system according to the first embodiment includes a managing device  11  and multiple operation servers  13  (hereinafter also merely referred to as “servers”) arranged in racks  12 . The managing device  11  and the operation servers  13  are connected to each other through a network  20 . 
         [0075]    Although  FIG. 1  illustrates a single rack  12 , the multiple racks  12  are included in the information processing system according to the first embodiment. In each of the racks  12 , multiple operation servers  13  are arranged. The managing device  11  is connected to the servers  13  through the network  20 . 
         [0076]    The operation servers  13  are an example of electronic devices. Each of the racks  12  is an example of a housing. In  FIG. 1 , the managing device  11  is arranged outside the rack  12 . The managing device  11 , however, may be arranged in the rack  12 . A specific operation server  13  arranged in the rack  12  may be used as the managing device  11 . 
         [0077]    The operation servers  13  have fans  14  for absorbing air within a room and cooling electronic parts (central processing units (CPUs) and the like) within the servers  13 . White arrows illustrated in  FIG. 1  indicate directions in which the air flows by the fans  14 . 
         [0078]    Hereinafter, surfaces of the racks  12  from which the air is absorbed into the racks  12  are referred to as absorption surfaces, while surfaces of the racks  12  from which the air is discharged from the racks  12  is referred to as discharge surfaces. The air that cools the electronic parts within the servers  13  and thereby increases in temperature is discharged from the discharge surfaces of the racks  12  to the outside of the racks  12 . 
         [0079]      FIG. 1  illustrates an example in which the fans  14  are arranged in housings of the servers  13 . The fans  14 , however, may be arranged outside the housings of the servers  13 . 
         [0080]    The servers  13  have temperature sensors  15   a  and temperature sensors  15   b . The temperature sensors  15   a  are arranged on the sides of the absorption surfaces of the racks  12  and configured to detect temperatures of the air that has flowed into the racks  12 , while the temperature sensors  15   b  are arranged on the sides of the discharge surfaces of the racks  12  and configured to detect temperatures of the servers  13 . 
         [0081]      FIG. 2  is a top view of an operation server  13 . In each of the operation servers  13 , the temperature sensor  15   a  is arranged at a position indicated by an ellipse A, and the temperature sensor  15   b  is arranged at a position indicated by an ellipse B, for example. 
         [0082]    In general servers, the temperature sensors  15   a  and  15   b  and base management controllers (BMCs)  16  are mounted as standard. The general servers may transmit information indicating temperatures of air on the sides of absorption and temperatures of the general servers to an external device through the BMCs  16 . The external device may control the fans  14  of the general servers through the BMCs  16 , turn on power sources of the general servers through the BMCs  16 , and turn off the power sources of the general servers through the BMCs  16 . 
         [0083]    In the first embodiment, the aforementioned general servers are used as the operation servers  13 , while temperature sensors  15   a  and  15   b  and BMCs  16  are not additionally prepared. A symbol  13   a  illustrated in  FIG. 2  indicates CPUs (heat generating parts) installed in the server  13 . 
         [0084]    The managing device  11  is a computer and includes a CPU  11   a , a storage device  17 , and a memory  19 , as illustrated in  FIG. 1 . Dedicated software is stored in the storage device  17 . As illustrated in  FIG. 3 , the managing device  11  includes a controller  18   a , a collector  18   b , and an associator  18   c . These functional blocks included in the managing device  11  are achieved by reading the software. 
         [0085]    As described later, the collector  18   b  collects temperature information of the servers  13  from the temperature sensors  15   a  and  15   b . The associator  18   c  associates the servers  13  with identification information (the positions of the servers in the racks  12  in the following example) specific to the servers  13  based on changes in the temperature information collected by the collector  18   b . The controller  18   a  controls operations of the servers  13  and executes processes in accordance with set procedures. 
         [0086]      FIGS. 4, 5, and 6  are flowcharts of a control method to be executed by the information processing system according to the first embodiment. 
         [0087]    In the first embodiment, specific management network addresses are set in the operation servers  13  by a network administrator in advance, respectively. Specific serial numbers (IDs) are set in the operation servers  13  by a manufacturer in advance, respectively. The managing device  11  may acquire the serial numbers from the operation servers  13  through the BMCs  16 . In addition, management network addresses of operation servers  13  arranged on top shelves (uppermost shelves) of the racks  12  are identified in advance. 
         [0088]    First, in S 11 , the managing device  11  (controller  18   a ) generates a managed device information table on the memory  19 . The managed device information table has a table identification number item, a management network address item, a serial number item, and a rack position number item, as illustrated in  FIG. 7 , for example.  FIG. 7  illustrates an example in which five operation servers  13  are arranged in a rack  12 . 
         [0089]    Next, a process illustrated in  FIG. 4  proceeds to S 12  and the managing device  11  (collector  18   b ) accesses, through the network  20 , all servers  13  to be managed and acquires management network addresses of the servers  13 . Then, the managing device  11  (collector  18   b ) records the acquired management network addresses in the managed device information table, as illustrated in  FIG. 7 . 
         [0090]    In the example illustrated in  FIG. 7 , table identification numbers are given to the operation servers  13  with the detected management network addresses in the order of the management network addresses. 
         [0091]    Next, the process proceeds to S 13  and the managing device  11  (controller  18   a ) records 1 as a rack position number of an operation server  13  arranged on the top shelf (uppermost shelf) of the rack  12 , as illustrated in  FIG. 8 . 
         [0092]    The rack position number 1 indicates that the operation server  13  is arranged on the top shelf of the rack  12 . As described above, the management network address of the operation server  13  arranged on the top shelf of the rack  12  is identified in advance. In this example, the operation server  13  with a management network address “192.168.0.11” is arranged on the top shelf of the rack  12 . 
         [0093]    Next, the process proceeds to S 14  and the managing device  11  (collector  18   b ) accesses the operation servers  13  through the network  20  and acquires serial numbers (IDs) of the servers  13 . Then, the managing device  11  (collector  18   b ) associates the serial numbers of the servers  13  with the table identification numbers and the management network addresses and records the serial numbers of the servers  13  in the managed device information table, as illustrated in  FIG. 9 . 
         [0094]    Next, the process proceeds to S 15  and the managing device  11  (controller  18   a ) selects a single server  13  from among the servers  13  to be managed. In this case, the managing device  11  selects the servers  13  in the order of the management network addresses. Thus, the server  13  with the management network address “192.168.0.11” (table identification number 1) is selected first. The order in which the servers  13  are selected, however, is not limited to this. 
         [0095]    After that, the process proceeds to S 16  and the managing device  11  executes a sub-process. The sub-process is described below with reference to  FIG. 5 . 
         [0096]    In S 21 , the managing device  11  (collector  18   b ) accesses, through the network  20 , all the servers to be managed and acquires absorbed air temperatures Ta and inside temperatures Ti of the servers  13 . The absorbed air temperatures Ta are detected by the temperature sensors  15   a , while the inside temperatures Ti are detected by the temperature sensors  15   b.    
         [0097]    Subsequently, the managing device  11  (controller  18   a ) calculates the differences ΔT (=Ti−Ta) between the inside temperatures Ti and the absorbed air temperatures Ta for the operation servers  13  and generates a temperature management information table on the memory  19 . 
         [0098]      FIG. 10  is a diagram illustrating an example of the temperature management information table. In  FIG. 10 , indices 0 for Ta, Ti, and ΔT indicate values (initial values) measured in the sub-process executed for the first time. 
         [0099]    As illustrated in  FIG. 10 , in the temperature management information table, the absorbed air temperatures Ta and inside temperatures Ti of the servers  13  and the differences ΔT between the inside temperatures Ti and the absorbed air temperatures Ta are recorded for the table identification numbers. 
         [0100]    Next, the sub-process proceeds to S 22  and the managing device  11  (controller  18   a ) stops the fan  14  of the selected server  13  (server with the table identification number 1 in the sub-process executed for the first time) through the network  20  and the BMC  16  of the selected server  13 . 
         [0101]    In this case, the fan  14  may not be stopped. However, in order to reduce a time period for which the inside temperature Ti increases upon an operation of the server  13  in the next process, the fan  14  is stopped in S 22  in the first embodiment. In order to further reduce the time period for which the inside temperature Ti increases, a specific program may be executed and apply a load to the CPUs included in the server  13 . 
         [0102]    Next, the sub-process proceeds to S 23  and the managing device  11  (controller  18   a ) turns on a power source of the selected server  13  through the network  20  and the BMC  16  of the selected server  13  and thereby causes the server  13  to operate. Due to the operation of the server  13 , the CPUs and I/O (input/output) of the server  13  are heated and the temperature Ti of the server  13  increases. The CPUs and the I/O are examples of heat generating parts. 
         [0103]    Next, the sub-process proceeds to S 24  and the managing device  11  (controller  18   a ) stands by (looping) until the difference ΔT of the selected server  13  increases by a predetermined temperature (of 10° C. in this example) or higher from an initial value of the difference ΔT. Then, when the difference ΔT of the selected server  13  increases by the predetermined temperature or higher from the initial value, the sub-process proceeds to S 25 . 
         [0104]    In S 25 , the managing device  11  (controller  18   a ) accesses, through the network  20 , all the servers  13  to be managed and acquires the absorbed air temperatures Ta and inside temperatures Ti of the servers  13 . The managing device  11  (controller  18   a ) calculates the differences ΔT between the absorbed air temperatures Ta and inside temperatures Ti of all the servers  13  to be managed. Then, the managing device  11  (controller  18   a ) stores the absorbed air temperatures Ta, the inside temperatures Ti, and the differences ΔT in the temperature management information table. 
         [0105]      FIG. 11  illustrates the temperature management information table in which absorbed air temperatures Ta 1 , inside temperatures Ti 1 , and the differences ΔT 1  between the absorbed air temperatures Ta 1  and the inside temperatures Ti 1  when the server  13  with the table identification number 1 operates are recorded. 
         [0106]    Next, the sub-process proceeds to S 26  and the managing device  11  (controller  18   a ) controls a rotation rate of the fan  14  of the selected server  13  so as to set the rotation rate of the fan  14  to the maximum rotation rate through the network  20  and the BMC  16  of the selected server  13 . In S 27 , the managing device  11  (controller  18   a ) turns off the power source of the selected server  13 . 
         [0107]    The rotation rate of the fan  14  is set to the maximum rotation rate in S 26  in order to reduce a time period for which the inside temperature Ti of the server  13  is reduced to an initial value (or the inside temperature Ti before the power source is turned on). In S 27 , the server  13  may become a sleep state or an idle state, instead of the turning-off of the power source of the server  13 . 
         [0108]    Next, the sub-process proceeds to S 28  and the managing device  11  (controller  18   a ) stands by (looping) until the difference ΔT of the server  13  that operates in S 23  becomes equal to or nearly equal to the initial value (or the difference ΔT before the server  13  operates). When the difference ΔT of the operating server  13  becomes equal to or nearly equal to the initial value, the sub-process proceeds to S 29  and the managing device  11  (controller  18   a ) returns control of the fan  14  of the server  13  to normal control (so that the rotation rate of the fan  14  is based on the inside temperature Ti, for example). Then, the managing device  11  terminates the sub-process and causes the process to proceed to S 17  illustrated in  FIG. 4 . 
         [0109]    In S 52 , the managing device  11  (controller  18   a ) determines whether or not the sub-process was executed on all the servers  13  to be managed. If the managing device  11  (controller  18   a ) determines that the sub-process is yet to be executed on at least any of all the servers  13  to be managed (No in S 17 ), the process returns to S 15  and the managing device  11  (controller  18   a ) selects a next server  13  among servers  13  that are yet to be subjected to the sub-process. After that, in S 16 , the sub-process (of S 21  to S 29 ) illustrated in  FIG. 5  is executed on the selected server  13 . 
         [0110]      FIG. 12  illustrates initial values of absorbed air temperatures Ta and inside temperatures Ti obtained in the sub-process executed for the first and second times, the differences ΔT between the initial values of the temperatures Ta and Ti obtained in the sub-process executed for the first and second times, values of absorbed air temperatures Ta and inside temperatures Ti obtained when specific servers (servers selected in S 15 ) operate, and the differences ΔT between the temperatures Ta and Ti obtained when the specific servers operate. 
         [0111]    As illustrated in  FIG. 12 , initial values of absorbed air temperatures Ta, initial values of inside temperatures Ti, the differences ΔT between the initial values of the temperatures Ta and Ti, values of absorbed air temperatures Ta and inside temperatures Ti when a server operates, and the differences ΔT between the temperatures Ta and Ti when the server operates, are recorded in the temperature management information table for each execution of the sub-process. 
         [0112]    If the managing device  11  (controller  18   a ) determines that the sub-process was executed on all the servers  13  to be managed (Yes in S 17 ), the process proceeds to S 18 . Then, the managing device  11  (controller  18   a ) generates a temperature change table from the temperature management information table and stores the generated temperature change table in the storage device  17 . 
         [0113]      FIG. 13  is a diagram illustrating an example of the temperature change table. As illustrated in  FIG. 13 , in the temperature change table, the differences ΔT between the absorbed air temperatures Ta and inside temperatures Ti of all the servers  13  when a specific server (server selected in S 15 ) operates are recorded for each execution of the sub-process. 
         [0114]    When generating the temperature change table, the managing device  11  starts a process indicated by the flowchart of  FIG. 6 . 
         [0115]    In S 31 , the managing device  11  (associator  18   c ) reads the temperature change table into the memory  19  from the storage device  17  and sets a variable N to 1 (N→1). 
         [0116]    Next, the process proceeds to S 32  and the managing device  11  (associator  18   c ) references the temperature change table and extracts a server whose difference ΔT changes by a threshold or larger when the server arranged on the top shelf of the rack  12  operates. 
         [0117]    In the first embodiment, the threshold is set to a value slightly lower than 2° C. The temperature change table illustrated in  FIG. 13  indicates that the difference ΔT between an absorbed air temperature Ta and inside temperature Ti of a server with a table identification number 5 changes by the threshold or larger when the server with the table identification number 1 operates. Thus, the managing device  11  (associator  18   c ) extracts the server with the table identification number 5. 
         [0118]    Next, the process proceeds to S 33  and the managing device  11  (associator  18   c ) determines whether or not the number of extracted servers is 1. If the number of extracted servers is 1 (Yes in S 33 ), the process proceeds to S 34 . If the number of extracted servers is 0 or 2 or larger (No in S 33 ), the managing device  11  assumes that an abnormality occurred for some reason and the managing device  11  terminates the process (abnormal termination). 
         [0119]    If the process proceeds from S 33  to S 34 , the managing device  11  (associator  18   c ) newly sets a value obtained by adding 1 to N to N (N+1→N). Then, the managing device  11  (associator  18   c ) determines that a rack position number of the server extracted in S 32  is N and the managing device  11  (associator  18   c ) records the determined rack position number in the managed device information table. 
         [0120]    Since the initial value of N is 1 as described above, the variable N becomes 2 in S 34 . Thus, the rack position number of the server  13  extracted in S 32  and having the table identification number 5 is “2”. Specifically, the server  13  with the table identification number 5 is determined as a server arranged on the second top shelf of the rack  12 . 
         [0121]    Next, the process proceeds to S 35  and the managing device  11  (associator  18   c ) extracts a server (however, a server with an undetermined rack position number) whose difference ΔT changes by the threshold or larger when the server  13  with the rack position number determined in S 34  operates. 
         [0122]    The temperature management information table illustrated in  FIG. 13  indicates that the differences ΔT of the servers with the table identification numbers 1 and 3 when the server with the table identification number 5 operates change by the threshold or larger. Since the rack position number of the server with the table identification number 1 is already determined to be “1”, the server with the table identification number 3 is extracted in S 35 . 
         [0123]    Next, the process proceeds to S 36  and the managing device  11  (associator  18   c ) determines whether or not the number of extracted servers is 1. If the number of extracted servers is 1 (Yes in S 36 ), the process proceeds to S 37 . If the number of extracted servers is 0 or 2 or larger (No in S 36 ), the managing device  11  assumes that an abnormality occurred for some reason and the managing device  11  terminates the process (abnormal termination). 
         [0124]    If the process proceeds from S 36  to S 37 , the managing device  11  newly sets a value obtained by adding 1 to N to N (N+1→N). Then, the managing device  11  sets, to N, a rack position number of the server extracted in S 35  and records the rack position number in the managed device information table. 
         [0125]    Since the variable N becomes 2 in S 34 , the variable N becomes 3 in S 37 . Thus, the rack position number of the server with the table identification number 3 is “3”. Specifically, the server  13  with the table identification number 3 is determined as a server arranged on the third top shelf of the rack  12 . 
         [0126]    Next, the process proceeds to S 38  and the managing device  11  (associator  18   c ) determines whether or not rack position numbers of all the servers  13  were determined. If the managing device  11  (associator  18   c ) determines that a rack position number of at least any of all the servers  13  is yet to be determined (No in S 38 ), the process returns to S 35  and the managing device  11  (associator  18   c ) extracts a next server and determines a rack position number of the extracted server in S 37 . 
         [0127]    By repeating a loop of S 35  to S 38  in the aforementioned manner, the rack position numbers of all the servers  13  to be managed are determined and recorded in the managed device information table.  FIG. 14  illustrates the managed device information table after the rack position numbers of all the servers  13  are recorded. 
         [0128]    If the managing device  11  (associator  18   c ) determines that the rack position numbers of all the servers  13  were determined (Yes in S 38 ), the managing device  11  terminates the process (normal termination). 
         [0129]    In the first embodiment, the temperature sensors  15   a  and  15   b  and BMCs  16  that are mounted as standard in the servers  13  are used, and the operation servers  13  are automatically associated with the positions of the operation servers  13  in the racks  12 . In the first embodiment, a module storing positional information and a sensor for acquiring the positional information are not used or a specific device such as a PDU is not used, and thus effects of improving general versatility and causing installation cost to be relatively low are obtained. 
         [0130]    The effects depend on the performance of the managing device  11 , the performance of the servers  13 , and the like. In the first embodiment, however, it takes about 6 minutes (excluding a time period for activation caused by turning-on of a power source) to determine the position of each server  13 . Processes of determining the positions of electronic devices (servers  13  and the like) arranged in the racks  12  may be executed in parallel. 
         [0131]    The first embodiment describes the case where the management network addresses of the servers  13  arranged on the top shelves (uppermost shelves) of the racks  12  are identified in advance. The techniques disclosed herein, however, are applicable to a case where management network addresses of servers  13  arranged on bottom shelves (lowermost shelves) of the racks  12  are identified in advance. In this case, rack position numbers of the servers  13  are determined in descending order, like a third embodiment described later. 
         [0132]    The first embodiment describes the case where the electronic devices are the operation servers. The electronic devices are not limited to the operation servers. A part or all of the electronic devices may be storage devices, switch devices, or the like. 
       Second Embodiment 
       [0133]      FIG. 15  is a schematic diagram illustrating an information processing system according to a second embodiment. In  FIG. 15 , parts that are the same as those illustrated in  FIG. 1  are indicated by the same reference numbers and symbols as those illustrated in  FIG. 1 . 
         [0134]    In the second embodiment, a network switch  21  is arranged on the top shelf (uppermost shelf) of a rack  12 , as illustrated in  FIG. 15 . The operation servers  13  are arranged on the second to sixth shelves of the rack  12 . 
         [0135]    The managing device  11  is connected to the operation servers  13  through the network switch  21 . The network switch  21  includes a fan  22 , a temperature sensor  23   a  for detecting a temperature on the side of air absorption, and a temperature sensor  23   b  for detecting temperatures of the servers  13 . 
         [0136]    Hereinafter, the network switch  21  and the operation servers  13  are collectively referred to as electronic devices. 
         [0137]      FIGS. 16, 17, and 18  are flowcharts of a control method to be executed by the information processing system according to the second embodiment. 
         [0138]    In the second embodiment, specific management network addresses are set in the electronic devices (network switch  21  and servers  13 ) by a network administrator in advance, respectively. Specific serial numbers (IDs) are set in the electronic devices by a manufacturer in advance, respectively. The managing device  11  may access the electronic devices and acquire the serial numbers from the electronic devices. 
         [0139]    In addition, the network switch  21  is identified to be arranged on the top shelf of the rack  12  and the management network address of the network switch  21  is identified. It is assumed that the management network address of the network switch  21  is “192.168.0.1”. 
         [0140]    In S 41 , the managing device  11  generates a managed device information table on the memory  19 . The managed device information table has a table identification number item, a management network address item, a serial number item, and a rack position number item, as illustrated in  FIG. 19 , for example. 
         [0141]    Next, a process illustrated in  FIG. 16  proceeds to S 42  and the managing device  11  accesses the electronic devices (network switch  21  and operation servers  13 ) through the network  20  and acquires management network addresses of the electronic devices. Then, the managing device  11  records the acquired management network addresses in the managed device information table, as illustrated in  FIG. 19 . 
         [0142]    In the example illustrated in  FIG. 19 , a table identification number of the network switch  21  is 1. Table identification numbers 2 to 6 are given to the operation servers  13  with the detected management network addresses in the order of the management network addresses. 
         [0143]    Next, the process proceeds to S 43  and the managing device  11  records 1 as a rack position number of the network switch  21  arranged on the top shelf of the rack  12 . 
         [0144]    Next, the process proceeds to S 44  and the managing device  11  accesses the electronic devices (network switch  21  and operation servers  13 ) through the network  20  and acquires the serial numbers (IDs) of the electronic devices. Then, the managing device  11  associates the serial numbers of the electronic devices with the table identification numbers and the management network addresses and records the serial numbers in the managed device information table, as illustrated in  FIG. 20 . 
         [0145]    Next, the process proceeds to S 45  and the managing device  11  selects a single server  13  among the servers  13  to be managed. The managing device  11  selects the servers  13  in the order of the management network addresses. Thus, the server  13  with the management network address “192.168.0.11” (table identification number 2) is selected first. 
         [0146]    After that, the process proceeds to S 46  and the managing device  11  executes a sub-process. The sub-process is described below with reference to  FIG. 17 . 
         [0147]    In S 51 , the managing device  11  accesses, through the network  20 , the electronic devices (network switch  21  and operation servers  13 ) and acquires absorbed air temperatures Ta and inside temperatures Ti of the electronic devices. 
         [0148]    Subsequently, the managing device  11  calculates the differences ΔT (=Ti−Ta) between the inside temperatures Ti and the absorbed air temperatures Ta for the electronic devices and generates a temperature management information table on the memory  19 . 
         [0149]      FIG. 21  is a diagram illustrating an example of the temperature management information table. As illustrated in  FIG. 21 , in the temperature management information table, the absorbed air temperatures Ta and inside temperatures Ti of the electronic devices (network switch  21  and operation servers  13 ) and the differences ΔT between the absorbed air temperatures Ta and the inside temperatures Ti are recorded. 
         [0150]    Next, the process proceeds to S 52  and the managing device  11  stops the fan  14  of the selected server  13  (server with the table identification number 2 in the sub-process executed for the first time) through the network  20  and the BMC  16  of the selected server  13 . 
         [0151]    Next, the process proceeds to S 53  and the managing device  11  turns on a power source of the selected server  13  through the network  20  and the BMC  16  of the selected server  13  and thereby causes the server  13  to operate. Due to the operation of the server  13 , the CPUs and I/O of the server  13  are heated and the inside temperature Ti of the server  13  increases. 
         [0152]    Next, the process proceeds to S 54  and the managing device  11  stands by (looping) until the difference ΔT of the selected server  13  increases by a predetermined temperature (of 10° C. in this example) or higher from an initial value of the difference ΔT. When the difference ΔT of the selected server  13  increases by the predetermined temperature or higher from the initial value, the process proceeds to S 55 . 
         [0153]    In S 55 , the managing device  11  accesses, through the network  20 , the electronic devices (network switch  21  and operation servers  13 ) to be managed and acquires the absorbed air temperatures Ta and inside temperatures Ti of the electronic devices. The managing device  11  calculates the differences ΔT between the absorbed air temperatures Ta and inside temperatures Ti of the electronic devices. Then, the managing device  11  stores the absorbed air temperatures Ta, the inside temperatures Ti, and the differences ΔT in the temperature management information table. 
         [0154]      FIG. 22  illustrates the temperature management information table in which absorbed air temperatures Ta 1 , inside temperatures Ti 1 , and the differences ΔT 1  between the absorbed air temperatures Ta 1  and the inside temperatures Ti 1  when the server  13  with the table identification number 2 operates are recorded. 
         [0155]    Next, the process proceeds to S 56  and the managing device  11  controls a rotation rate of the fan  14  of the selected server  13  so as to set the rotation rate to the maximum rotation rate through the network  20  and the BMC  16  of the selected server  13 . In S 57 , the managing device  11  turns off the power source of the server  13 . 
         [0156]    Next, the process proceeds to S 58  and the managing device  11  stands by (looping) until the difference ΔT of the server  13  whose power source is turned on in S 53  becomes equal to or nearly equal to the initial value (or the difference ΔT before the server  13  operates). When the difference ΔT of the server  13  whose power source is turned on becomes equal to or nearly equal to the initial value, the process proceeds to S 59  and the managing device  11  returns control of the fan  14  of the server  13  to normal control (so that the rotation rate of the fan  14  is based on the inside temperature Ti, for example). Then, the managing device  11  terminates the sub-process and causes the process to proceed to S 47  of the flowchart illustrated in  FIG. 16 . 
         [0157]    In S 47 , the managing device  11  determines whether or not the sub-process was executed on all the servers  13  to be managed. If the managing device  11  determines that the sub-process is yet to be executed on at least any of all the servers  13  to be managed (No in S 47 ), the process returns to S 45  and the managing device  11  selects a next server  13  among servers  13  that are yet to be subjected to the sub-process. After that, in S 46 , the managing device  11  executes the sub-process (of S 51  to S 59 ) illustrated in  FIG. 17 . 
         [0158]      FIG. 23  illustrates initial values of absorbed air temperatures Ta and inside temperatures Ti obtained in the sub-process executed for the first and second times, the differences ΔT between the initial values of the temperatures Ta and Ti obtained in the sub-process executed for the first and second times, values of absorbed air temperatures Ta and inside temperatures Ti obtained when specific servers (servers selected in S 45 ) operate, and the differences ΔT between the temperatures Ta and Ti obtained when the specific servers operate. 
         [0159]    As illustrated in  FIG. 23 , initial values of absorbed air temperatures Ta, initial values of inside temperatures Ti, the differences ΔT between the initial values of the temperatures Ta and Ti, values of absorbed air temperatures Ta and inside temperatures Ti when a server operates, and the differences ΔT between the temperatures Ta and Ti when the server operates, are recorded in the temperature management information table for each execution of the sub-process. 
         [0160]    If the managing device  11  determines whether or not the sub-process was executed on all the servers  13  to be managed (Yes in S 47 ), the process proceeds to S 48 . Then, the managing device  11  generates a temperature change table from the temperature management information table and stores the generated temperature change table in the storage device  17 . 
         [0161]      FIG. 24  is a diagram illustrating an example of the temperature change table. As illustrated in  FIG. 24 , in the temperature change table, the differences ΔT between absorbed air temperatures Ta and inside temperatures Ti of the electronic devices when a specific server (server selected in S 45 ) operates are recorded for each execution of the sub-process. 
         [0162]    When generating the temperature change table, the managing device  11  starts a process indicated by the flowchart of  FIG. 18 . 
         [0163]    In S 61 , the managing device  11  reads the temperature change table into the memory  19  from the storage device  17  and sets the variable N to 1 (N→1). 
         [0164]    Next, the process proceeds to S 62  and the managing device  11  references the temperature change table and extracts a server that is arranged on the top shelf of the rack  12  and operates and causes the difference ΔT of the network switch  21  to change by a threshold or larger. 
         [0165]    In the second embodiment, the threshold is set to a value slightly lower than 2° C. The temperature change table illustrated in  FIG. 24  indicates that the difference ΔT of the network switch  21  changes by the threshold or larger when the server with the table identification number 2 operates. Thus, the managing device  11  extracts the server with the table identification number 2. 
         [0166]    Next, the process proceeds to S 63  and the managing device  11  determines whether or not the number of extracted servers is 1. If the number of extracted servers is 1 (Yes in S 63 ), the process proceeds to S 64 . If the number of extracted servers is 0 or 2 or larger (No in S 63 ), the managing device  11  assumes that an abnormality occurred for some reason and the managing device  11  terminates the process (abnormal termination). 
         [0167]    If the process proceeds from S 63  to S 64 , the managing device  11  newly sets a value obtained by adding 1 to N to N (N+1→N). Then, the managing device  11  determines that a rack position number of the server extracted in S 62  is N and the managing device  11  records the rack position number in the managed device information table. 
         [0168]    Since the initial value of N is 1 as described above, the variable N becomes 2 in S 64 . Thus, the rack position number of the server  13  extracted in S 62  and having the table identification number 2 is “2”. Specifically, the server  13  with the table identification number 2 is determined as a server arranged on the second top shelf of the rack  12 . 
         [0169]    Next, the process proceeds to S 65  and the managing device  11  extracts a server (however, a server with an undetermined rack position number) whose difference ΔT changes by the threshold or larger when the server  13  with the rack position number determined in S 64  operates. 
         [0170]    The temperature management information table illustrated in  FIG. 24  indicates that the difference ΔT between an absorbed air temperature Ta and inside temperature of a server with a table identification number 6 changes by the threshold or larger when the server with the table identification number 2 operates. Thus, the server with the table identification number 6 is extracted in S 65 . 
         [0171]    Next, the process proceeds to S 66  and the managing device  11  determines whether or not the number of extracted servers is 1. If the number of extracted servers is 1 (Yes in S 66 ), the process proceeds to S 67 . If the number of extracted servers is 0 or 2 or larger (No in S 66 ), the managing device  11  assumes that an abnormality occurred for some reason and the managing device  11  terminates the process (abnormal termination). 
         [0172]    If the process proceeds from S 66  to S 67 , the managing device  11  newly sets a value obtained by adding 1 to N to N (N+1→N). Then, the managing device  11  sets, to N, a rack position number of the server extracted in S 65  and records the rack position number in the managed device information table. 
         [0173]    Since the variable N becomes 2 in S 64 , the variable N becomes 3 in S 67 . Thus, the rack position number of the server with the table identification number 6 is “3”. Specifically, the server  13  with the table identification number 6 is determined as a server arranged on the third top shelf of the rack  12 . 
         [0174]    Next, the process proceeds to S 68  and the managing device  11  determines whether or not rack position numbers of all the servers  13  were determined. If the managing device  11  determines that a rack position number of at least any of all the servers  13  is yet to be determined (No in S 68 ), the process returns to S 65  and the managing device  11  extracts a next server and determines a rack position number of the extracted server in S 67 . 
         [0175]    By repeating a loop of S 65  to S 68  in the aforementioned manner, the rack position numbers of all the servers  13  to be managed are determined and recorded in the managed device information table.  FIG. 25  illustrates the managed device information table after the rack position numbers of all the servers  13  are recorded. 
         [0176]    If the managing device  11  determines that the rack position numbers of all the servers  13  to be managed were determined (Yes in S 68 ), the managing device  11  terminates the process (normal termination). 
         [0177]    In the second embodiment, the temperature sensors  15   a  and  15   b  and BMCs  16  that are mounted as standard in the servers  13  are used, and the operation servers  13  are automatically associated with the positions of the operation servers  13  in the rack  12 . In the second embodiment, a module storing positional information and a sensor for acquiring the positional information are not used or a specific device such as a PDU is not used, and thus effects of improving general versatility and causing installation cost to be relatively low are obtained. 
       Third Embodiment 
       [0178]      FIG. 26  is a schematic diagram illustrating an information processing system according to the third embodiment. In  FIG. 26 , parts that are the same as those illustrated in  FIG. 15  are indicated by the same reference numbers and symbols as those illustrated in  FIG. 15 . 
         [0179]    In the third embodiment, the network switch  21  is arranged on the bottom shelf (sixth shelf) of the rack  12 , as illustrated in  FIG. 26 . The operation servers  13  are arranged on the first to fifth shelves of the rack  12 . 
         [0180]      FIGS. 27, 28, and 29  are flowcharts of a control method to be executed by the information processing system according to the third embodiment. 
         [0181]    In the third embodiment, specific management network addresses are set in the electronic devices (network switch  21  and servers  13 ) by the network administrator in advance, respectively. Specific serial numbers (IDs) are set in the electronic devices by the manufacturer in advance, respectively. The managing device  11  may access the electronic devices and acquire the serial numbers from the electronic devices. 
         [0182]    In addition, the network switch  21  is identified to be arranged on the bottom shelf of the rack  12 . The management network address of the network switch  21  is identified. It is assumed that the management network address of the network switch  21  is “192.168.0.1”. 
         [0183]    In S 71 , the managing device  11  generates a managed device information table on the memory  19 . The managed device information table has a table identification number item, a management network address item, a serial number item, and a rack position number item, as illustrated in  FIG. 30 , for example. 
         [0184]    Next, a process illustrated in  FIG. 27  proceeds to S 72  and the managing device  11  accesses, through the network  20 , the electronic devices (network switch  21  and operation servers  13 ) to be managed and acquires the management network addresses of the electronic devices. Then, the managing device  11  records the acquired management network addresses in the managed device information table, as illustrated in  FIG. 30 . 
         [0185]    In the example illustrated in  FIG. 30 , the table identification number of the network switch  21  is 1. The table identification numbers 2 to 6 are given to the operation servers  13  with the detected management network addresses in the order of the table identification numbers. 
         [0186]    Next, the process proceeds to S 73  and the managing device  11  records 6 as a rack position number of the network switch  21  arranged on the bottom shelf (sixth shelf) of the rack  12 . 
         [0187]    Then, the process proceeds to S 74  and the managing device  11  accesses the electronic devices (network switch  21  and operation servers  13 ) through the network  20  and acquires the serial numbers (IDs) of the electronic devices. Then, the managing device  11  associates the serial numbers of the electronic devices with the table identification numbers and the management network addresses and records the serial numbers in the managed device information table, as illustrated in  FIG. 31 . 
         [0188]    Next, the process proceeds to S 75  and the managing device  11  selects a single server  13  from among the servers  13  to be managed. The managing device  11  selects the servers  13  in the order of the management network addresses. Thus, the server  13  with the management network address “192.168.0.11” (table identification number 2) is selected first. 
         [0189]    After that, the process proceeds to S 76  and the managing device  11  executes a sub-process. The sub-process is described below with reference to  FIG. 28 . 
         [0190]    In S 81 , the managing device  11  accesses, through the network  20 , the electronic devices (network switch  21  and operation servers  13 ) to be managed and acquires absorbed air temperatures Ta and inside temperatures Ti of the electronic devices. 
         [0191]    Then, the managing device  11  calculates the differences ΔT (=Ti−Ta) between the inside temperatures Ti and the absorbed air temperatures Ta for the electronic devices and generates a temperature management information table on the memory  19 . 
         [0192]      FIG. 32  is a diagram illustrating an example of the temperature management information table. As illustrated in  FIG. 32 , in the temperature management information table, the absorbed air temperatures Ta and inside temperatures Ti of the electronic devices (network switch  21  and operation servers  13 ) and the differences ΔT between the absorbed air temperatures Ta and the inside temperatures Ti are recorded in the temperature management information table for the table identification numbers. 
         [0193]    Next, the process proceeds to S 82  and the managing device  11  stops the fan  14  of the selected server  13  (server with the table identification number 2 in the sub-process executed for the first time) through the network  20  and the BMC  16  of the selected server  13 . 
         [0194]    Next, the process proceeds to S 83  and the managing device  11  turns on a power source of the selected server  13  through the network  20  and the BMC  16  of the selected server  13  and thereby causes the selected server  13  to operate. Due to the operation of the server  13 , the CPUs and I/O of the server  13  are heated and the inside temperature Ti of the server  13  increases. 
         [0195]    Next, the process proceeds to S 84  and the managing device  11  stands by (looping) until the difference ΔT of the selected server  13  increases by a predetermined temperature (of 10° C. in this example) or higher from an initial value of the difference ΔT. When the difference ΔT of the selected server  13  increases by the predetermined temperature or higher from the initial value, the process proceeds to S 85 . 
         [0196]    In S 85 , the managing device  11  accesses, through the network  20 , the electronic devices (network switch  21  and operation servers  13 ) to be managed and acquires the absorbed air temperatures Ta and inside temperatures Ti of the electronic devices. The managing device  11  calculates the differences ΔT between the absorbed air temperatures Ta and inside temperatures Ti of the electronic devices. Then, the managing devices stores the absorbed air temperatures Ta, the inside temperatures Ti, and the differences ΔT in the temperature management information table. 
         [0197]      FIG. 33  illustrates the temperature management information table in which absorbed air temperatures Ta 1 , inside temperatures Ti 1 , and the differences ΔT 1  between the absorbed air temperature Ta 1  and the inside temperatures Ti 1  when the server  13  with the table identification number 2 operates are recorded. 
         [0198]    Next, the process proceeds to S 86  and the managing device  11  controls a rotation rate of the fan  14  of the selected server  13  through the network  20  and the BMC  16  of the selected server  13  so as to set the rotation rate to the maximum rotation rate. Subsequently, in S 87 , the managing device  11  turns off the power source of the selected server  13 . 
         [0199]    Next, the process proceeds to S 88  and the managing device  11  stands by (looping) until the difference ΔT of the server  13  that operates in S 83  becomes equal to or nearly equal to the initial value (or the difference ΔT before the server  13  operates). When the difference ΔT of the server  13  that operates in S 83  becomes equal to or nearly equal to the initial value, the process proceeds to S 89  and the managing device  11  returns control of the fan  14  of the server  13  to normal control (so that the rotation rate is based on the inside temperature Ti, for example). Then, the managing device  11  terminates the sub-process and causes the process to proceed to S 77  of the flowchart illustrated in  FIG. 27 . 
         [0200]    In S 77 , the managing device  11  determines whether or not the sub-process was executed on all the servers  13  to be managed. If the managing device  11  determines that the sub-process is yet to be executed on at least any of all the servers  13  to be managed (No in S 77 ), the process returns to S 75  and the managing device  11  selects a next server  13  from among servers  13  that are yet to be subjected to the sub-process. After that, in S 76 , the sub-process (of S 81  to S 89 ) illustrated in  FIG. 28  is executed on the selected server  13 . 
         [0201]      FIG. 34  illustrates initial values of absorbed air temperatures Ta and inside temperatures Ti obtained in the sub-process executed for the first and second times, the differences ΔT between the initial values of the temperatures Ta and Ti obtained in the sub-process executed for the first and second times, values of absorbed air temperatures Ta and inside temperatures Ti obtained when specific servers (servers selected in S 75 ) operate, and the differences ΔT between the temperatures Ta and Ti obtained when the specific servers operate. 
         [0202]    As illustrated in  FIG. 34 , initial values of absorbed air temperatures Ta, initial values of inside temperatures Ti, the differences ΔT between the initial values of the temperatures Ta and Ti, values of absorbed air temperatures Ta and inside temperatures Ti when a server operates, and the differences ΔT between the temperatures Ta and Ti when the server operates, are recorded in the temperature management information table for each execution of the sub-process. 
         [0203]    If the managing device  11  determines that the sub-process was executed on all the servers  13  to be managed (Yes in S 77 ), the process proceeds to S 78 . Then, the managing device  11  generates a temperature change table from the temperature management information table and stores the generated temperature change table in the storage device  17 . 
         [0204]      FIG. 35  is a diagram illustrating an example of the temperature change table. As illustrated in  FIG. 35 , in the temperature change table, the differences ΔT between absorbed air temperatures Ta and inside temperatures Ti of the electronic devices when a specific server (server selected in S 75 ) are recorded for each execution of the sub-process. 
         [0205]    When generating the temperature change table, the managing device  11  starts a process indicated by the flowchart of  FIG. 29 . 
         [0206]    In S 91 , the managing device  11  reads the temperature change table into the memory  19  from the storage device  17  and sets the variable N to 6 (N→6). 
         [0207]    Next, the process proceeds to S 92  and the managing device  11  references the temperature change table and extracts a server that operates and causes the difference ΔT of the network switch  21  arranged on the bottom shelf of the rack  12  to change by a threshold or larger. 
         [0208]    In the third embodiment, the threshold is set to a value slightly lower than 2° C. The temperature change table illustrated in  FIG. 35  indicates that the difference ΔT of the network switch  21  (with the table identification number 1) when the server with the table identification number 3 operates changes by the threshold or larger. Thus, the managing device  11  extracts the server  3  with the table identification number 3. 
         [0209]    Next, the process proceeds to S 93  and the managing device  11  determines whether or not the number of extracted servers is 1. If the number of extracted servers is 1 (Yes in S 93 ), the process proceeds to S 94 . If the number of extracted servers is 0 or 2 or larger (No in S 93 ), the managing device  11  assumes that an abnormality occurred for some reason and the managing device  11  terminates the process (abnormal termination). 
         [0210]    If the process proceeds from S 93  to S 94 , the managing device  11  newly sets a value obtained by subtracting 1 from N to N (N−1→N). Then, the managing device  11  determines that a rack position number of the server extracted in S 92  is N and the managing device  11  records the rack position number in the managed device information table. 
         [0211]    Since the initial value of N is 6 as described above, the variable N becomes 5 in S 94 . Thus, the rack position number of the server  13  extracted in S 92  and having the table identification number 3 is “5”. Specifically, the server  13  with the table identification number 3 is determined as a server arranged on the fifth top shelf of the rack  12 . 
         [0212]    Next, the process proceeds to S 95  and the managing device  11  extracts a server (however, a server with an undetermined rack position number) whose difference ΔT changes by the threshold or larger when the server  13  with the rack position number determined in S 94  operates. 
         [0213]    The temperature management information table illustrated in  FIG. 35  indicates that the difference ΔT of the server with the table identification number 5 changes by the threshold or larger when the server with the table identification number 3 operates. Thus, the server with the table identification number 5 is extracted in S 95 . 
         [0214]    Next, the process proceeds to S 96  and the managing device  11  determines whether or not the number of extracted servers is 1. If the number of extracted servers is 1 (Yes in S 96 ), the process proceeds to S 97 . If the number of extracted servers is 0 or 2 or larger (No in S 96 ), the managing device  11  assumes that an abnormality occurred for some reason and the managing device  11  terminates the process (abnormal termination). 
         [0215]    If the process proceeds from S 96  to S 97 , the managing device  11  newly sets a value obtained by subtracting 1 from N to N (N−1→N). Then, the managing device  11  sets, to N, a rack position number of the server extracted in S 95  and records the rack position number in the managed device information table. 
         [0216]    Since the variable N becomes 5 in S 94 , the variable N becomes 4 in S 97 . Thus, the rack position number of the server with the table identification number 5 is “4”. Specifically, the server  13  with the table identification number 5 is determined as a server arranged on the fourth top shelf of the rack  12 . 
         [0217]    Next, the process proceeds to S 98  and the managing device  11  determines whether or not rack position numbers of all the servers  13  were determined. If the managing device  11  determines that a rack position number of at least any of all the servers  13  is yet to be determined (No in S 98 ), the process returns to S 95  and the managing device  11  extracts a next server in S 95  and determines a rack position number of the extracted server in S 97 . 
         [0218]    By repeating a loop of S 95  to S 98  in the aforementioned manner, the rack position numbers of all the servers  13  to be managed are determined and recorded in the managed device information table.  FIG. 36  illustrates the managed device information table after the rack position numbers of all the servers  13  are recorded. 
         [0219]    If the managing device  11  determines that the rack position numbers of all the servers  13  to be managed were determined (Yes in S 98 ), the managing device  11  terminates the process (normal termination). 
         [0220]    In the third embodiment, the temperature sensors  15   a  and  15   b  and BMCs  16  that are mounted as standard in the servers  13  are used and the operation servers  13  are automatically associated with the positions of the operation servers  13  in the racks  12 . In the third embodiment, a module storing positional information and a sensor for acquiring the positional information are not used or a specific device such as a PDU is not used, and thus effects of improving general versatility and causing installation cost to be relatively low are obtained. 
       Fourth Embodiment 
       [0221]      FIG. 37  is a schematic diagram illustrating an information processing system according to a fourth embodiment. In  FIG. 37 , parts that are the same as those illustrated in  FIG. 15  are indicated by the same reference numbers and symbols as those illustrated in  FIG. 15 . 
         [0222]    In the fourth embodiment, as illustrated in  FIG. 37 , the network switch  21  is arranged on a middle shelf of the rack  12 . The operation servers  13  are arranged on the other shelves of the rack  12 . 
         [0223]    The managing device  11  is connected to the operation servers  13  through the network switch  21 . The network switch  21  has the fan  22 , the temperature sensor  23   a  for detecting a temperature on the side of air absorption, and the temperature sensor  23   b  for detecting temperatures of the operation servers  13 . 
         [0224]      FIGS. 38, 39, 40, and 41  are flowcharts of a control method to be executed by the information processing system according to the fourth embodiment. 
         [0225]    In the fourth embodiment, specific management network addresses are set in the electronic devices (network switch  21  and servers  13 ) by the network administrator in advance, respectively. Specific serial numbers (IDs) are set in the electronic devices by the manufacturer in advance, respectively. The managing device  11  may access the electronic devices and acquire the serial numbers from the electronic devices. 
         [0226]    It is assumed that a management network address of an operation server  13  arranged on the top shelf (uppermost shelf) of the rack  12  is identified in advance. It is assumed that the management network address of the operation server  13  arranged on the top shelf (uppermost shelf) of the rack  12  is “192.168.0.11”. 
         [0227]    In S 101 , the managing device  11  generates a managed device information table on the memory  19 . The managed device information table has a table identification number item, a management network address item, a serial number item, and a rack position number item, as illustrated in  FIG. 42 , for example. 
         [0228]    Next, a process illustrated in  FIG. 38  proceeds to S 102  and the managing device  11  accesses, through the network  20 , the electronic devices (network switch  21  and operation servers  13 ) to be managed and acquires the management network addresses of the electronic devices. Then, the managing device  11  records the management network addresses in the managed device information table, as illustrated in  FIG. 42 . 
         [0229]    Next, the process proceeds to S 103  and the managing device  11  records 1 as a rack position number of the operation server  13  arranged on the top shelf of the rack  12 , as illustrated in  FIG. 43 . As described above, the management network address of the operation server  13  arranged on the top shelf of the rack  12  is identified in advance. The managed device information table illustrated in  FIG. 43  indicates that the server  13  with the table identification number 2 is arranged on the top shelf of the rack  12 . 
         [0230]    Next, the process proceeds to S 104  and the managing device  11  accesses, through the network  20 , the electronic devices (network switch  21  and operation servers  13 ) to be managed and acquires the serial numbers (IDs) of the electronic devices. Then, the managing device  11  associates the serial numbers of the electronic devices with the table identification numbers and the management network addresses and records the serial numbers in the managed device information table, as illustrated in  FIG. 43 . 
         [0231]    Next, the process proceeds to S 105  and the managing device  11  selects a single server  13  from among the servers  13  to be managed. The managing device  11  selects the servers  13  in the order of the management network addresses. Thus, the server  13  with the management network address “192.168.0.11” (table identification number 2) is selected first. 
         [0232]    After that, the process proceeds to S 46  and the managing device  11  executes a sub-process. The sub-process is described below with reference to  FIG. 39 . 
         [0233]    In S 111 , the managing device  11  accesses, through the network  20 , the electronic devices (network switch  21  and operation servers  13 ) to be managed and acquires absorbed air temperatures Ta and inside temperatures Ti of the electronic devices. 
         [0234]    Then, the managing device  11  calculates the differences ΔT (=Ti−Ta) between the inside temperatures Ti and the absorbed air temperatures Ta for the electronic devices and generates a temperature management information table on the memory  19 . 
         [0235]      FIG. 44  is a diagram illustrating an example of the temperature management information table. As illustrated in  FIG. 44 , in the temperature management information table, the absorbed air temperatures Ta and inside temperatures Ti of the electronic devices (network switch  21  and operation servers  13 ) and the differences ΔT between the absorbed air temperatures Ta and the inside temperatures Ti are recorded for the table identification numbers. 
         [0236]    Next, the process proceeds to S 112  and the managing device  11  stops the fan  14  of the selected server  13  (server  13  with the table identification number 2 in the sub-process executed for the first time) through the network  20  and the BMC  16  of the selected server  13 . 
         [0237]    Next, the process proceeds to S 113  and the managing device  11  turns on a power source of the selected server  13  through the network  20  and the BMC  16  of the selected server  13  and thereby causes the server  13  to operate. Due to the operation of the server  13 , the CPUs and I/O of the server  13  are heated and the inside temperature Ti of the server  13  increases. 
         [0238]    Next, the process proceeds to S 114  and the managing device  11  stands by (looping) until the difference ΔT of the selected server  13  increases by a predetermined temperature (of 10° C. in this example) or higher from an initial value of the difference ΔT. When the difference ΔT of the selected server  13  increases by the predetermined temperature or higher from the initial value, the process proceeds to S 115 . 
         [0239]    In S 115 , the managing device  11  accesses, through the network  20 , the electronic devices (network switch  21  and operation servers  13 ) to be managed and acquires the absorbed air temperatures Ta and inside temperatures Ti of the electronic devices. The managing device  11  calculates the differences ΔT between the absorbed air temperatures Ta and inside temperatures Ti of the electronic devices. Then, the managing device  11  stores the absorbed air temperatures Ta, the inside temperatures Ti, and the differences ΔT in the temperature management information table. 
         [0240]      FIG. 45  illustrates the temperature management information table in which absorbed air temperatures Ta 1 , inside temperatures Ti 1 , and the differences ΔT 1  between the absorbed air temperatures Ta 1  and the inside temperatures Ti 1  when the server  13  with the table identification number 2 operates are recorded. 
         [0241]    Next, the process proceeds to S 116  and the managing device  11  controls a rotation rate of the fan  14  of the selected server  13  through the network  20  and the BMC  16  of the selected server  13  so as to set the rotation rate to the maximum rotation rate. Subsequently, in S 117 , the managing device  11  turns off the power source of the selected server  13 . 
         [0242]    Next, the process proceeds to S 118  and the managing device  11  stands by (looping) until the difference ΔT of the server  13  that operates in S 113  becomes equal to or nearly equal to the initial value (or the difference ΔT before the server  13  operates). When the difference ΔT of the server  13  that operates in S 113  becomes equal to or nearly equal to the initial value, the process proceeds to S 119  and the managing device  11  returns control of the fan  14  of the server  13  to normal control (so that the rotation rate of the fan  14  is based on the inside temperature Ti, for example). Then, the managing device  11  terminates the sub-process and causes the process to proceed to S 107  of the flowchart illustrated in  FIG. 38 . 
         [0243]    In S 107 , the managing device  11  determines whether or not the sub-process was executed on all the servers  13  to be managed. If the managing device  11  determines that the sub-process is yet to be executed on at least any of all the servers  13  to be managed (No in S 107 ), the process returns to S 105  and the managing device  11  selects a next server  13  from among servers  13  that are yet to be subjected to the sub-process. After that, in S 106 , the managing device  11  executes the sub-process (of S 111  to S 119 ) illustrated in  FIG. 39 . 
         [0244]      FIG. 46  illustrates initial values of absorbed air temperatures Ta and inside temperatures Ti obtained in the sub-process executed for the first and second times, the differences ΔT between the initial values of the temperatures Ta and Ti obtained in the sub-process executed for the first and second times, values of absorbed air temperatures Ta and inside temperatures Ti obtained when specific servers (servers selected in S 105 ) operate, and the differences ΔT between the temperatures Ta and Ti obtained when the specific servers operate. 
         [0245]    As illustrated in  FIG. 46 , initial values of absorbed air temperatures Ta, initial values of inside temperatures Ti, the differences ΔT between the initial values of the temperatures Ta and Ti, values of absorbed air temperatures Ta and inside temperatures Ti when a server operates, and the differences ΔT between the temperatures Ta and Ti when the server operates, are recorded in the temperature management information table for each execution of the sub-process. 
         [0246]    If the managing device  11  determines that the sub-process was executed on all the servers  13  to be managed (Yes in S 107 ), the process proceeds to S 108 . Then, the managing device  11  generates a temperature change table from the temperature management information table and stores the generated temperature change table in the storage device  17 . 
         [0247]      FIG. 47  is a diagram illustrating an example of the temperature change table. As illustrated in  FIG. 47 , in the temperature change table, the differences ΔT between absorbed air temperatures Ta and inside temperatures Ti of the electronic devices when a specific server (selected in S 105 ) operates are recorded for each execution of the sub-process. 
         [0248]    When generating the temperature change table, the managing device  11  starts a process indicated by the flowchart of  FIGS. 40 and 41 . 
         [0249]    In S 121 , the managing device  11  reads the temperature change table into the memory  19  from the storage device  17  and sets the variable N to 1 (N→1). 
         [0250]    Next, the process proceeds to S 122  and the managing device  11  references the temperature change table and extracts an electronic device whose difference ΔT changes by a threshold or larger when the server  13  (server with the table identification number 2) arranged on the top shelf of the rack  12  operates. 
         [0251]    In the fourth embodiment, the threshold is set to a value slightly lower than 2° C. The temperature change table illustrated in  FIG. 47  indicates that the difference ΔT of the server  13  with the table identification number 6 changes by the threshold or larger when the server with the table identification number 2 operates. Thus, the managing device  11  extracts the server with the table identification number 6. 
         [0252]    Next, the process proceeds to S 123  and the managing device  11  determines whether or not the number of extracted electronic devices is 1. If the number of extracted electronic devices is 1 (Yes in S 123 ), the process proceeds to S 124 . If the number of extracted electronic devices is 0 or 2 or larger (No in S 123 ), the managing device  11  assumes that an abnormality occurred for some reason and the managing device  11  terminates the process (abnormal termination). 
         [0253]    If the process proceeds from S 123  to S 124 , the managing device  11  newly sets a value obtained by adding 1 to N to N (N+1→N). Then, the managing device  11  determines that a rack position number of the electronic device extracted in S 122  is N and the managing device  11  records the rack position number in the managed device information table. 
         [0254]    Since the initial value of N is 1 as described above, the variable N becomes 2 in S 124 . Thus, the rack position number of the electronic device extracted in S 122  and having the table identification number 6 is “2”. Specifically, the electronic device with the table identification number 6 is determined to be arranged on the second top shelf of the rack  12 . 
         [0255]    Next, the process proceeds to S 125  and the managing device  11  determines whether or not the electronic device extracted in S 122  is a server  13 . In the determination, the management network addresses and the serial numbers are used. 
         [0256]    For example, the management network addresses assigned to the operation servers  13  and the network switch  21  are stored in the managing device  11  in advance. Thus, the managing device  11  may determine, based on the management network addresses, that the electronic device with the table identification number 6 is the operation server  13 . If the managing device  11  determines that the extracted electronic device is the server (Yes in S 125 ), the process proceeds from S 125  to S 126 . 
         [0257]    In S 126 , the managing device  11  extracts an electronic device with an undetermined rack position number from electronic devices whose differences ΔT change by the threshold or larger when the server (server with the table identification number 6) with the determined rack position number operates. In the example illustrated in  FIG. 47 , when the server  13  with the table identification number 6 operates, the differences ΔT of the electronic devices with the table identification numbers 1 and 2 change by the threshold or larger. Since the rack position number of the electronic device with the table identification number 2 is determined to be “1”, the electronic device extracted in S 126  has the table identification number 1. 
         [0258]    After that, in S 127 , the managing device  11  determines whether or not the number of extracted electronic devices is 1. If the number of extracted electronic devices is 1 (Yes in S 127 ), the process proceeds to S 128 . If the number of extracted electronic devices is 0 or 2 or larger (No in S 127 ), the managing device  11  assumes that an abnormality occurred for some reason and the managing device  11  terminates the process (abnormal termination). 
         [0259]    If the process proceeds from S 127  to S 128 , the managing device  11  newly sets a value obtained by adding 1 to N to N (N+1→N). Then, the managing device  11  sets, to N, a rack position number of the electronic device extracted in S 127  and records the rack position number in the managed device information table. 
         [0260]    Since the variable N becomes 2 in S 124 , the variable N becomes 3 in S 128 . Thus, the rack position number of the electronic device with the table identification number 1 is “3”. Specifically, the electronic device with the table identification number 1 is determined to be arranged on the third top shelf of the rack  12 . 
         [0261]    Next, the process proceeds to S 129  and the managing device  11  determines whether or not rack position numbers of all the electronic devices were determined. If the managing device  11  determines that a rack position number of at least any of all the electronic devices is yet to be determined (No in S 129 ), the process returns to S 125  and the managing device  11  extracts a next electronic device. 
         [0262]    In the aforementioned case, the rack position numbers of the electronic devices with the table identification numbers 1, 6, and 2 are already determined, but the rack position numbers of the electronic devices with the table identification numbers 3, 4, and 5 are yet to be determined. Thus, the process proceeds from S 129  to S 125 . 
         [0263]    If the managing device  11  determines that the rack position numbers of all the electronic devices were determined in S 129 , the network switch  21  is not detected and thus the managing device  11  assumes that an abnormality occurred for some reason and the managing device  11  terminates the process (abnormal termination). 
         [0264]    If the electronic device with the table identification number 1 is extracted in S 126  and the process proceeds from S 129  to S 125 , the managing device  11  determines that the extracted electronic device is the network switch  21  based on the management network addresses and the serial numbers. Thus, the process proceeds from S 125  to S 131 . 
         [0265]    In S 131 , the managing device  11  extracts a server  13  whose rack position number is yet to be determined and that causes the difference ΔT of the electronic device (network switch  21 ) with the table identification number 1 to change by the threshold or larger. In the example illustrated in  FIG. 47 , the servers with the table identification numbers 4 and 6 cause the difference ΔT of the electronic device with the table identification number 1 to change by the threshold or larger. Since the rack position number of the server with the table identification number 6 is already determined to be “2”, the server with the table identification number 4 is extracted in S 131 . 
         [0266]    Next, the process proceeds to S 132  and the managing device  11  determines whether or not the number of extracted servers is 1. If the number of extracted servers is 1 (Yes in S 132 ), the process proceeds to S 133 . If the number of extracted servers is 0 or 2 or larger (No in S 132 ), the managing device  11  assumes that an abnormality occurred for some reason and the managing device  11  terminates the process (abnormal termination). 
         [0267]    In S 133 , the managing device  11  newly sets a value obtained by adding 1 to N to N (N+1→N). Then, the managing device  11  sets, to N, a rack position number of the server extracted in S 131  and records the rack position number in the managed device information table. 
         [0268]    Since the variable N becomes 3 in S 128 , the variable N becomes 4 in S 133 . Thus, the rack position number of the server with the table identification number 4 is “4”. 
         [0269]    Next, the process proceeds to S 134  and the managing device  11  extracts an electronic device (however, an electronic device with an undetermined rack position number) whose difference ΔT changes by the threshold or larger when the server with the rack position number determined in S 133  operates. 
         [0270]    The temperature change table illustrated in  FIG. 47  indicates that the differences ΔT of the electronic devices with the table identification numbers 1 and 5 change by the threshold or larger when the server with the table identification number 4 operates. Since the rack position number of the electronic device with the table identification number 1 is already determined to be “3”, the electronic device with the table identification number 5 is extracted in S 134 . 
         [0271]    Next, the process proceeds to S 135  and the managing device  11  determines whether or not the number of extracted electronic devices is 1. If the number of extracted electronic devices is 1 (Yes in S 135 ), the process proceeds to S 136 . If the number of extracted electronic devices is 0 or 2 or larger (No in S 136 ), the managing device  11  assumes that an abnormality occurred for some reason and the managing device  11  terminates the process (abnormal termination). 
         [0272]    Next, in S 136 , the managing device  11  newly sets a value obtained by adding 1 to N to N (N+1→N). Then, the managing device  11  sets, to N, a rack position number of the electronic device extracted in S 134  and records the rack position number in the managed device information table. 
         [0273]    Since the variable N becomes 4 in S 133 , the variable N becomes 5 in S 136 . Thus, the rack position number of the electronic device (server  13 ) with the table identification number 5 is “5”. 
         [0274]    Next, the process proceeds to S 137  and the managing device  11  determines whether or not rack position numbers of all the electronic devices to be managed were determined. If the managing device  11  determines that a rack position number of at least any of all the electronic devices to be managed is yet to be determined (No in S 137 ), the process returns to S 134  and the managing device  11  extracts an electronic device whose rack position number will be determined next. Subsequently, in S 136 , the managing device  11  determines the rack position number. In this manner, the rack position numbers of all the electronic devices to be managed are determined. If the managing device  11  determines that the rack position numbers of all the electronic devices to be managed were determined in S 137 , the managing device  11  terminates the process (normal termination). 
         [0275]      FIG. 48  illustrates the managed device information table after the rack position numbers of the electronic devices (network switch  21  and operation servers  13 ) are recorded. 
         [0276]    In the fourth embodiment, the temperature sensors  15   a  and  15   b  and BMCs  16  that are mounted as standard in the servers  13  are used, and the operation servers  13  are automatically associated with the positions of the operation servers  13  in the racks  12 . In the fourth embodiment, a module storing positional information and a sensor for acquiring the positional information are not used or a specific device such as a PDU is not used, and thus effects of improving general versatility and causing installation cost to be relatively low are obtained. 
       Fifth Embodiment 
       [0277]      FIG. 49  is a schematic diagram illustrating an information processing system according to a fifth embodiment. In  FIG. 49 , parts that are the same as those illustrated in  FIG. 1  are indicated by the same reference numbers and symbols as those illustrated in  FIG. 1 . 
         [0278]    In the fifth embodiment, five servers  13  are arranged side by side in a rack  12 , as illustrated in  FIG. 47 . In the same manner as the first embodiment, the servers  13  each have a fan  14 , temperature sensors  15   a  and  15   b  and a BMC  16  (refer to  FIG. 1 ). The managing device  11  is connected to the servers  13  through the network  20 . 
         [0279]      FIGS. 50, 51, and 52  are flowcharts of a control method to be executed by the information processing system according to the fifth embodiment. 
         [0280]    In the fifth embodiment, specific management network addresses are set in the electronic devices (network switch  21  and servers  13 ) by the network administrator in advance, respectively. Specific serial numbers (IDs) are set in the electronic devices by the manufacturer in advance, respectively. The managing device  11  may acquire the serial numbers from the operation servers  13  through the BMCs  16 . It is assumed that a management network address of an operation server  13  arranged on the leftmost side of the rack  12  is identified in advance. 
         [0281]    In S 141 , the managing device  11  generates a managed device information table on the memory  19 . The managed device information table has a table identification number item, a management network address item, a serial number item, and a rack position number item, as illustrated in  FIG. 53 , for example. 
         [0282]    Next, a process illustrated in  FIG. 50  proceeds to S 142  and the managing device  11  accesses, through the network  20 , all the servers  13  to be managed and acquires the management network addresses of the servers  13 . Then, the managing device  11  records the management network addresses in the managed device information table, as illustrated in  FIG. 53 . 
         [0283]    In the example illustrated in  FIG. 53 , table identification numbers are given to the operation servers  13  with the detected management network addresses in the order of the management network addresses. 
         [0284]    Next, the process proceeds to S 143  and the managing device  11  records 1 as a rack position number of the operation server  13  arranged on the leftmost side of the rack  12 , as illustrated in  FIG. 8 . 
         [0285]    The rack position number 1 indicates that the operation server  13  is arranged on the leftmost side of the rack  12 . As described above, the management network address of the operation server  13  arranged on the leftmost side of the rack  12  is identified in advance. In this example, the operation server  13  with the management network address “192.168.0.11” is arranged on the leftmost side of the rack  12 . 
         [0286]    Next, the process proceeds to S 144  and the managing device  11  accesses the operation servers  13  through the network  20  and acquires the serial numbers (IDs) of the servers  13 . Then, the managing device  11  associates the serial numbers of the servers  13  with the table identification numbers and the management network addresses and records the serial numbers in the managed device information table, as illustrated in  FIG. 55 . 
         [0287]    Next, the process proceeds to S 145  and the managing device  11  selects a single server  13  from among the servers  13  to be managed. The managing device  11  selects the servers  13  in the order of the management network addresses. Thus, the server  13  with the management network address “192.168.0.11” (table identification number 1) is selected first. 
         [0288]    After that, the process proceeds to S 146  and the managing device  11  executes a sub-process. The sub-process is described below with reference to  FIG. 51 . 
         [0289]    In S 151 , the managing device  11  accesses, through the network  20 , all the servers  13  to be managed and acquires absorbed air temperatures Ta and inside temperatures Ti of the servers  13 . Then, the managing device  11  calculates the differences ΔT (=Ti−Ta) between the inside temperatures Ti and the absorbed air temperatures Ta for the operation servers  13  and generates a temperature management information table on the memory  19 . 
         [0290]      FIG. 56  is a diagram illustrating an example of the temperature management information table. As illustrated in  FIG. 56 , in the temperature management information table, the absorbed air temperatures Ta and inside temperatures Ti of the servers  13  and the differences ΔT between the absorbed air temperatures Ta and the inside temperatures Ti are recorded for the table identification numbers. 
         [0291]    Next, the process proceeds to S 152  and the managing device  11  stops the fan  14  of the selected server  13  (server with the table identification number 1 in the sub-process executed for the first time) through the network  20 . 
         [0292]    Next, the process proceeds to S 153  and the managing device  11  turns on a power source of the selected server  13  through the network  20  and thereby causes the selected server  13  to operate. Due to the operation of the server  13 , the CPUs and I/O of the server  13  are heated and the inside temperature Ti of the server  13  increases. 
         [0293]    Next, the process proceeds to S 154  and the managing device  11  stands by (looping) until the difference ΔT of the selected server  13  increases by a predetermined temperature (of 10° C. in this example) or higher from an initial value of the difference ΔT. When the difference ΔT of the selected server  13  increases by the predetermined temperature or higher from the initial value, the process proceeds to S 155 . 
         [0294]    In S 155 , the managing device  11  accesses, through the network  20 , all the servers  13  to be managed and acquires the absorbed air temperatures Ta and inside temperatures Ti of the servers  13 . The managing device  11  calculates the differences ΔT between the absorbed air temperatures Ta and inside temperatures Ti of all the servers  13  to be managed. Then, the managing device  11  stores the absorbed air temperatures Ta, the inside temperatures Ti, and the differences ΔT in the temperature management information table. 
         [0295]      FIG. 57  illustrates the temperature management information table in which absorbed air temperatures Ta 1 , inside temperatures Ti 1 , and the differences ΔT 1  between the absorbed air temperatures Ta 1  and the inside temperatures Ti 1  when the server  13  with the table identification number 1 operates are recorded. 
         [0296]    Next, the process proceeds to S 156  and the managing device  11  controls a rotation rate of the fan  14  of the selected server  13  through the network  20  so as to set the rotation rate to the maximum rotation rate. Subsequently, in S 157 , the managing device  11  turns off the power source of the selected server  13 . 
         [0297]    Next, the process proceeds to S 158  and the managing device  11  stands by (looping) until the difference ΔT of the server  13  that operates in S 153  becomes equal to or nearly equal to an initial value (or the difference ΔT before the server  13  operates). When difference ΔT of the server  13  that operates in S 153  becomes equal to or nearly equal to the initial value, the process proceeds to S 159  and the managing device  11  returns control of the fan  14  of the server  13  to normal control (so that the rotation rate of the fan  14  is based on the inside temperature Ti, for example). Then, the managing device  11  terminates the sub-process and causes the process to proceed to S 147  of the flowchart illustrated in  FIG. 50 . 
         [0298]    In S 147 , the managing device  11  determines whether or not the sub-process was executed on all the servers  13  to be managed. If the managing device  11  determines that the sub-process is yet to be executed on at least any of all the servers  13  to be managed, the process returns to S 145  and the managing device  11  selects a next server  13  from among servers  13  that are yet to be subjected to the sub-process. After that, in S 146 , the sub-process (of S 151  to S 159 ) illustrated in  FIG. 51  is executed on the selected server  13 . 
         [0299]      FIG. 58  illustrates initial values of absorbed air temperatures Ta and inside temperatures Ti obtained in the sub-process executed for the first and second times, the differences ΔT between the initial values of the temperatures Ta and Ti obtained in the sub-process executed for the first and second times, values of absorbed air temperatures Ta and inside temperatures Ti obtained when specific servers (servers selected in S 145 ) operate, and the differences ΔT between the temperatures Ta and Ti obtained when the specific servers operate. 
         [0300]    As illustrated in  FIG. 58 , initial values of absorbed air temperatures Ta, initial values of inside temperatures Ti, the differences ΔT between the initial values of the temperatures Ta and Ti, values of absorbed air temperatures Ta and inside temperatures Ti when a server operates, and the differences ΔT between the temperatures Ta and Ti when the server operates, are recorded in the temperature management information table for each execution of the sub-process. 
         [0301]    If the managing device  11  determines that the sub-process was executed on all the servers  13  to be managed (Yes in S 147 ), the process proceeds to S 148 . Then, the managing device  11  generates a temperature change table from the temperature management information table and stores the generated temperature change table in the storage device  17 . 
         [0302]      FIG. 59  is a diagram illustrating an example of the temperature change table. As illustrated in  FIG. 59 , in the temperature change table, the differences ΔT between absorbed air temperatures Ta and inside temperatures Ti of all the servers  13  when a specific server (server selected in S 145 ) operates are recorded for each execution of the sub-process. 
         [0303]    When generating the temperature change table, the managing device  11  starts a process indicated by the flowchart of  FIG. 52 . 
         [0304]    In S 161 , the managing device  11  reads the temperature change table into the memory  19  from the storage device  17  and sets the variable N to 1 (N→1). 
         [0305]    Next, the process proceeds to S 162  and the managing device  11  references the temperature change table and extracts a server whose difference ΔT changes by a threshold or larger when the server arranged on the leftmost side of the rack  12  operates. 
         [0306]    In the fifth embodiment, the threshold is set to a value slightly lower than 2° C. The temperature change table illustrated in  FIG. 59  indicates that the difference ΔT of the server with the table identification number 5 changes by the threshold or larger when the server with the table identification number 1 operates. Thus, the managing device  11  extracts the server with the table identification number 5. 
         [0307]    Next, the process proceeds to S 163  and the managing device determines whether or not the number of extracted servers is 1. If the number of extracted servers is 1 (Yes in S 163 ), the process proceeds to S 164 . If the number of extracted servers is 0 or 2 or larger (No in S 163 ), the managing device  11  assumes that an abnormality occurred for some reason and the managing device  11  terminates the process (abnormal termination). 
         [0308]    If the process proceeds from S 163  to S 164 , the managing device  11  newly sets a value obtained by adding 1 to N to N (N+1→N). Then, the managing device  11  determines that a rack position number of the server extracted in S 162  is N and the managing device  11  records the rack position number in the managed device information table. 
         [0309]    Since the initial value of N is 1 as described above, the variable N becomes 2 in S 164 . Thus, the rack position number of the server  13  extracted in S 162  and having the table identification number 5 is “2”. Specifically, the server  13  with the table identification number 5 is determined as a server arranged on the second top shelf of the rack  12 . 
         [0310]    Next, the process proceeds to S 165  and the managing device  11  extracts a server (however, a server with an undetermined rack position number) whose difference ΔT changes by the threshold or larger when the server  13  with the rack position number determined in S 164  operates. 
         [0311]    The temperature management information table illustrated in  FIG. 59  indicates that the differences ΔT of the servers with the table identification numbers 1 and 3 change by the threshold or larger when the server with the table identification number 5 operates. Since the rack position number of the server with the table identification number 1 is already determined to be “1”, the server with the table identification number 3 is extracted in S 165 . 
         [0312]    Next, the process proceeds to S 166  and the managing device  11  determines whether or not the number of extracted servers is 1. If the number of extracted servers is 1 (Yes in S 166 ), the process proceeds to S 167 . If the number of extracted servers is 0 or 2 or larger (No in S 166 ), the managing device  11  assumes that an abnormality occurred for some reason and the managing device  11  terminates the process (abnormal termination). 
         [0313]    If the process proceeds from S 166  to S 167 , the managing device  11  newly sets a value obtained by adding 1 to N to N (N+1→N). Then, the managing device  11  sets, to N, a rack position number of the server extracted in S 165  and records the rack position number in the managed device information table. 
         [0314]    Since the variable N becomes 2 in S 164 , the variable N becomes 3 in S 167 . Thus, the rack position number of the server with the table identification number 3 is “3”. Specifically, the server  13  with the table identification number 3 is determined as a server arranged on the third shelf of the rack  12  from the left. 
         [0315]    Next, the process proceeds to S 168  and the managing device  11  determines whether or not rack position numbers of all the servers  13  were determined. If the managing device  11  determines that a rack position number of at least any of all the servers  13  is yet to be determined (No in S 168 ), the process returns to S 165  and the managing device  11  extracts a next server. Subsequently, in S 167 , the managing device  11  determines a rack position number of the extracted server. 
         [0316]    By repeating the loop of S 165  to S 168  in the aforementioned manner, the rack position numbers of all the servers  13  to be managed are determined and recorded in the managed device information table.  FIG. 60  illustrates the managed device information table after the rack position numbers of all the servers  13  are recorded. 
         [0317]    If the managing device  11  determines that the rack position numbers of all the servers  13  to be managed were determined (Yes in S 168 ), the managing device  11  terminates the process (normal termination). 
         [0318]    In the fifth embodiment, the temperature sensors  15   a  and  15   b  and BMCs  16  that are mounted as standard in the servers  13  are used, and the operation servers  13  are automatically associated with the positions of the operation servers  13  in the racks  12 . In the fifth embodiment, a module storing positional information and a sensor for acquiring the positional information are not used or a specific device such as a PDU is not used, and thus effects of improving general versatility and causing installation cost to be relatively low are obtained. 
         [0319]    All examples and conditional language recited herein are intended for pedagogical purposes to aid the reader in understanding the invention and the concepts contributed by the inventor to furthering the art, and are to be construed as being without limitation to such specifically recited examples and conditions, nor does the organization of such examples in the specification relate to a showing of the superiority and inferiority of the invention. Although the embodiments of the present invention have been described in detail, it should be understood that the various changes, substitutions, and alterations could be made hereto without departing from the spirit and scope of the invention.