JP4325048B2 - Boot server selection system - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a boot server selection system for selecting a boot server on a network from which a network computer receives a bootstrap program necessary for startup.
[0002]
[Prior art]
A network computer does not have a mass storage device such as a hard disk for storing software like a normal personal computer, but receives software from the resources of servers connected to the network via the network. It functions as a computer.
[0003]
The boot server supplies a bootstrap program, which is software necessary for startup, when a network computer connected to the network is turned on and the user tries to start using it.
[0004]
FIG. 2 is an explanatory diagram of the boot server selection system. Here, the signal flow when the NCa 203 of the network computers NCa203, NCb204, and NCc205 connected to the network 206 is turned on at the start of use is shown.
[0005]
When the boot request 208 is broadcast and transmitted to the network 206, the boot server A 201 and the boot server B 202 connected to the network 206 receive the boot request 208 and transmit a boot response 207 or 209, respectively. Thereafter, the network computer NCa203 that has received the response performs a boot process with the boot server that sent the response that was received first, and the system operation of the network computer NCa203 is started.
[0006]
As described above, conventionally, by connecting a plurality of boot servers for network computers on the network, even if one of the boot servers fails, the boot program can be supplied from the remaining boot servers. I was able to.
[0007]
As a result, the network computer can be activated if any one of the plurality of boot servers on the network to which the network computer belongs operates normally.
[0008]
FIG. 15 is an operation explanatory diagram of a conventional boot server selection system. FIG. 15 shows an example of the signal flow of the boot server selection system shown in FIG.
[0009]
The boot request transmitted from the network computer NCa1501 is received as 1504 or 1505 by the boot server A 1502 and the boot server B 1503 via a network (not shown). Each boot server sends a response to the network at a timing according to the progress of each process.
[0010]
The response is received by each boot server and network computer. This figure shows a case where a response 1506 from the boot server A 1502 happens to be received by the network computer NCa 1501 first, and a state in which the boot process 1510 is executed with the boot server A 1502 is shown. The response 1508 from the boot server B 1503 arrives at the network NCa 1501 with a delay, but this is discarded.
[0011]
[Problems to be solved by the invention]
As can be seen from the above description of the conventional boot server selection system, it is undefined which boot server responds first to a message broadcast by a network computer at startup.
[0012]
In other words, without specifying the boot server to be used by the administrator, one of the boot servers installed on the network is automatically selected according to the timing determined by the system environment and performance. A problem arises that the network system administrator cannot manage the operation of each computer.
[0013]
Further, when a boot server connected to the same network as the network computer fails, even if there is a boot server connected to another network, the network computer cannot be started using the boot server.
[0014]
In view of these points, the present invention
An object of the present invention is to provide means for selecting from which boot server a network computer is connected on one network or a complex network.
[0015]
[Means for Solving the Problems]
The above problem is solved by a boot server selection system configured as described below and a boot server or a boot relay device that configures the system.
[0016]
FIG. 1 is a block diagram of the present invention.
[0017]
In FIG. 1, 20 is a network computer, and 10 is a boot server that performs a boot process in response to a boot request from the network computer 20 on the network.
[0018]
11 is a boot request receiving means for receiving a boot request from the network computer 20, and 12 is a time passage detecting means for detecting the passage of a preset time. Reference numeral 13 denotes boot response transmission means for transmitting a boot response when the time elapsed detection means 12 activated after receiving the boot request detects the passage of time.
[0019]
By the above means, the boot server 10 that first responds to the boot request transmitted by the network computer 20 executes the boot process of the network computer 20. In other words, the boot server that responds first can be determined based on the time from when the request is received for each boot server set in advance to when the response is transmitted. Also, even if the boot server response order is determined by setting the time to response in this way, depending on the boot server status, it may not be possible to respond immediately. When the boot server that has been set so as to respond in the next order when it fails, the boot process is performed with the network computer when the response is made after the set time has elapsed.
[0020]
As described above, the order of selecting a plurality of boot servers installed as a countermeasure against the failure can be controlled only by setting the response timing to each boot server. (Claim 1, Claim 2, Claim 6)
FIG. 3 is an explanatory diagram of the operation of the boot server (Claim 2), and FIG. 4 is a flowchart of the operation of the boot server (Claim 2). The boot server A302 is set to T1 as the waiting time until the response after receiving the request, and the boot server B303 is set to T2. When T1 <T2, the boot process 310 is executed using the response b306. When the network computer NC301 cannot receive the response b, the boot processing 311 is executed using the response c309.
[0021]
In the operation flowchart of FIG. 4, in step S41, the boot server waits for a signal. Here, in particular, when a boot request from a network computer is waited and a boot request message sent to the network is received, a timer value is set for each boot server in step S42. The set waiting time Tn is set as the response monitoring time. It then waits for the timer to complete.
[0022]
When the timeout occurs, a boot response to the boot request is sent to the network in step S43. Each boot server controls the timing of the boot response by the response monitoring time Tn. (Claim 2)
Next, in claim 3, the boot server 10 in FIG. 1 receives a boot response transmitted from another boot server installed on the same network as the network computer, and stores the received boot response. The response reception means 14 is additionally provided so that the boot response transmission means 13 suppresses the transmission of the boot response when the boot response reception means 14 stores that the boot response has been received. This reduces the number of signals on the network and the processing of each boot server by preventing other boot servers connected to the same network from processing subsequent boot responses when they have already returned a boot response. I am trying.
[0023]
FIG. 5 shows an operation explanatory diagram of the boot server (Claim 3), and FIG. 6 shows an operation flowchart of the boot server (Claim 3).
[0024]
In FIG. 5, the network computer NC501 sends the request a to the network, but the boot server A502 is out of order and cannot respond after receiving the request a504, or cannot even receive it and cannot send the response b to the network. Shows the signal flow.
[0025]
Since the boot server B 503 cannot receive the response b transmitted from the boot server A 502 until the own monitoring time T 2, the boot server B 503 waits for the elapse of T 2 time after receiving the request a 505 and sends a response c 507. The network computer NC501 executes a boot process with the boot server B503 using the response c508.
[0026]
Also, if the boot server A502 operates normally and sends a response b before the time T2, the boot server B503 receives the response b before the time T2 and does not send the response c. Therefore, the subsequent processing corresponding to the request a505 is not performed.
[0027]
This will be explained with reference to the flowchart of FIG. 6. When a boot request message is received in step S61, when a boot request message is received, a timer is issued in step S62, the timer is completed, and a response is received from another server. Become. At this time, a timer value Tn determined for each boot server is set.
[0028]
If another response is received here, control is transferred to step S61 so that the request is discarded in step S64 without waiting for completion of the timer and a new boot request is waited. If a time-out occurs without receiving a response, a response is transmitted in step S63 and the network computer is booted. (Claim 3)
In the above, a system for selecting a boot server on the same network that performs boot processing in response to a boot request from a network computer has been shown. However, from the following, a boot server on another network connected by a router or the like is used. 1 shows a boot server selection system including a boot relay device when boot processing is performed.
[0029]
In FIG. 1, 30 is a boot relay device that relays a boot request of the network computer 20 to another network, 31 is a boot request receiving means for receiving a boot request from the network computer 20 via the network, and 32 is Time elapse detecting means for detecting elapse of a preset time, 33 is a boot response receiving means for receiving the boot response transmitted from the boot server 10 and storing the reception, and 34 is activated after receiving the boot request. Boot request relay means for relaying a boot request to a boot server or a boot relay device on another network set in advance when the passage of time detection means 32 detects the passage of time and the reception of the boot response is not stored. It is.
[0030]
FIG. 7 is an explanatory diagram of a boot relay device in the boot server selection system. The configuration of the boot server selection system includes three networks 723, 721, and 724 including a network computer and a boot server, a boot relay device having a function of connecting the networks, and a network 722 connected to each other by a router. Is.
[0031]
For convenience of explanation, it is assumed that the network computer that makes a boot request is NCa 709 and the boot server A 705 on the network 723 cannot respond due to a failure. Therefore, there is no boot server that responds to boot on the network 723, and a boot request is sent to the boot server on another network via the boot relay device X706 to perform boot processing with the boot server that has obtained the boot response. Show the case.
[0032]
The boot relay device X706 designates the boot server C702 on the network 721 or the boot server D708 on the network 724, and relays and transmits the boot request from the network computer NCa709. The network 722 and the network 721 are connected by a router M701, and the network 722 and the network 724 are connected by a router N707. The operation of the boot relay device will be described below.
[0033]
FIG. 8 is a diagram for explaining the operation of the boot relay device (Claim 4), and FIG. 9 is a flowchart for the operation of the boot relay device (Claim 4).
[0034]
In FIG. 8, the boot relay device X 803 is connected to the same network as the network computer NC 801 and the boot server A 802, and the request a transmitted by the 801 is received as 806. Since the boot server A 802 cannot respond due to the occurrence of a failure, when the waiting time T2 until the response after the request set in 803 elapses, the boot relay device responds to the boot server C 804 on another preset network. The request a806 is relayed as 808 and transmitted.
[0035]
The boot server C804 can set the time from the reception of the boot request to the boot response in the same manner as the other boot servers, but the response can be returned immediately by setting this time to zero. The response c810 is transmitted as a response c809 to the requesting network computer NC801 via the boot relay device X803.
[0036]
The network computer NC801 executes the boot process 811 with the boot server C804 using the response c809 received first.
[0037]
The operation of the boot server relay device will be described according to the steps of the flowchart of FIG. While waiting for the reception of the boot request in step S91, if the request message is received, the received request is stored in step S92. Immediately issue a timer for monitoring the time after reception, and wait for completion of the timer and reception of a response from another boot server.
[0038]
When a response is received, the request is discarded in step S93, and the process returns to step S91 to wait for the next request. By receiving a boot response from another boot server, it is understood that the boot process of the network computer has been performed by the boot server that responded, so it is not necessary to continue the processing of the stored boot request. Processing will be terminated.
[0039]
On the other hand, when a timeout occurs, no boot server on the same network has responded to the boot request for some reason, so that the boot request detected and stored in step S94 is set in the boot relay device. Relay to other boot servers on the network. Thereafter, when a boot response is received from the destination boot server, the boot relay device relays the response and transmits it to the requesting network computer in step S95, and returns to step S91 to wait for a new request.
[0040]
The network computer that has received the response executes boot processing with the boot server of the other network that has responded. As a result, even if a boot server on the same network does not function, or there is no boot server on the same network, the boot relay device can be connected to a boot server on another network to perform boot processing. can do. (Claim 4, Claim 7)
Although the boot relay device described above has a relay function to a specific boot server on another network, one or more boot servers or boot relays connected to the boot relay device on an arbitrary number of arbitrary networks It is also possible to have a function of storing and setting devices and relaying them to these devices.
[0041]
In the boot relay device 30 of FIG. 1, 35 monitors the boot request relay priority corresponding to the boot request relay selection order of one or more boot servers or boot relay devices on another network, and the boot response after the boot request relay. A device-by-device response waiting time storage means for storing the boot response waiting time, 36 designates one or more boot servers or boot relay devices stored in the device-by-device response waiting time storage means 35 as relay destination devices in the order of selection priority of boot request relay It is a relay order setting means for setting the response waiting time stored and correspondingly stored in the time passage detection means 32 to set the relay order of the boot requests. The boot request relay means 34 is received by the relay order setting means 36. Relay the boot request to the configured boot server or boot relay device,
The time elapse detection means 32 detects the elapse of time, and when the reception of the boot response is not stored, the boot request relay means 34 is activated again. An example of these operations and a flowchart will be described below.
[0042]
FIG. 10 and FIG. 11 are diagrams for explaining the operation of the boot relay device (Claim 5) and an operation flowchart of the boot relay device (Claim 5).
[0043]
Since the boot server A705 on the same network as the boot relay device X706 of the boot server selection system shown in FIG. 7 is out of order, one or more boot server boot servers C702 connected to other networks (also assumed to be faulty), An example of the operation when sequentially specifying and selecting the boot server D708 will be described.
[0044]
In FIG. 10, first, a boot request a transmitted from the network computer NC1001 is transmitted to the boot server A1002 and the boot relay device X1003 on the same network.
[0045]
The boot relay device X1003 receives the request and sets the response monitoring time T2 of its own other boot server in the timer. Since the boot server A 1002 cannot transmit a response due to the occurrence of a failure, the boot relay device X 1003 relays and transmits the request a as 1009 to the boot server C 1004 after T2 time without receiving a response from the boot server of the same network. It is assumed that the boot server C1004 and the boot server D1005 are set and stored as response monitoring times T3 and T4 as boot servers on other networks in the boot relay device.
[0046]
Since the boot server C1004 cannot respond, the boot relay device X relays the request a as 1010 to the boot server D1005 after T3 time by the timer. The boot server D immediately transmits a response d to the boot relay device X1003. The boot relay device X also immediately relays it and transmits it to the network computer NC1001.
[0047]
The network computer NC1001 that has received the relayed response 1012 executes the boot process 1014 with the response source boot server D1005.
[0048]
FIG. 11 shows an operation flowchart of a boot relay device that relays a boot request from a network computer to one or more other boot servers or boot relay devices on the network. The operation will be described below step by step.
[0049]
In step S111, the boot relay apparatus waits for a boot request that can be received. When the request message is received, the received boot request is cached in step S112. That is, the boot request to be relayed is stored.
[0050]
In step S113, similarly to the other boot servers, a monitoring time for waiting for reception of a boot response from another boot server after receiving a boot request is set in the timer to wait for completion of the timer. The boot relay device also monitors the response to the boot request relayed by itself. Further, here, a response reception wait is also performed.
[0051]
When it receives a response from a boot server on the same network as itself, it is no longer necessary to relay the request, so the boot request stored in step S114 is discarded and the process returns to step S111 to wait for a new boot request.
[0052]
When time-out occurs, in step S115, the relay server boot server is searched for a stored table (not shown), and the boot server or boot relay device name stored in order of relay priority and the time for monitoring each response are extracted. To do. The boot request is relayed and transmitted to the boot server or boot relay device on the other extracted network, and the process waits for a response in step S117 and returns to step S113. In step S113, the extracted monitoring time Tn is set in a timer to wait for completion.
[0053]
When a response is received from a boot server in another network, control is transferred to step S116, and the response is relayed to the network computer. The stored request is discarded and the process returns to step S111 to wait for a new boot request.
[0054]
As described above, the boot relay device monitors the response of the boot server on its own network, and when none responds, it sequentially relays the boot request to one or more boot servers on another network to obtain the response. The computer boot process can be performed.
[0055]
Further, the relay of the boot request can relay the network to other boot relay devices in multiple stages and connect the boot server to the network computer to execute the boot process. As a result, the boot server can be selected flexibly, and appropriate boot server placement and failure countermeasures can be performed.
[0056]
DETAILED DESCRIPTION OF THE INVENTION
In the present embodiment, a form realized by a computer program executed on a computer used for a general purpose such as a personal computer or workstation used for a server or a node computer such as a router. Indicates.
[0057]
The boot server selection system of the present invention is realized by executing a computer program on a computer including a processing device, a main storage device, an auxiliary storage device, an input / output device, and the like. The computer program is stored and provided in a portable medium such as a floppy disk or CD-ROM, or in a main storage device or auxiliary storage device of another computer connected to the network. The recording medium of the present invention corresponds to the portable medium, the main storage device, and the auxiliary storage device.
[0058]
The provided computer program is loaded directly from the portable medium into the main storage device of the computer, or once copied or installed from the portable medium to the auxiliary storage device, then loaded into the main storage device and executed. In addition, when the data is stored and provided in another device connected to the network, it is copied to the auxiliary storage device after being received from the other device via the network, and loaded into the main storage device for execution.
[0059]
FIG. 12 shows a configuration diagram of the embodiment of the present invention. The embodiment of the present invention uses a boot server on each network as a boot server for booting network computers on other networks in a system in which a large number of network computers are installed and operated on each floor network. This is a boot server selection system that can be used. As a result, an economical and practical network computer system can be constructed by applying a boot server on another network to the same network without installing many boot servers on the same network. It is also possible to set the boot server to be forced by a network computer on multiple floors.
[0060]
In FIG. 12, a network computer and a boot server are arranged on four networks. These networks are connected by a boot relay device or a router.
[0061]
In FIG. 12, 1220, 1216, 1221, and 1217 are networks installed on each floor, 1220 includes network computers 1212 and 1213 and a boot server 1207, 1216 includes a network computer 1203 and a boot server 1202, and 1221 includes The network computers 1214 and 1215 and the boot server 1210 are operated while the network computer 1205 and the boot server 1204 are connected to 1217 and operated. There are 1218 and 1219 as networks connecting these networks, and the network of the network computer system on each floor is connected by boot relay devices 1208 or 1209 and routers 1201 and 1211 via these networks. Here, the boot relay device also has a router function, but the server may have this function.
[0062]
In this embodiment, as an example, the network computer NCa 1212 transmits a boot request, and a boot server selection system is set in which each boot server is set to have a role of a standby machine for boot processing in sequence. Each network has one boot server as an example, but a plurality of boot servers may be provided, or in some cases, 0 boot servers may be provided.
[0063]
Although the boot server selection priority order of the network computer NCa1212 shown as an example here is determined by the setting of the time monitoring table of each device, the structure of the table can be created symmetrically, so the same effect can be obtained for network computers on any network. It is easy to show.
[0064]
FIG. 13 illustrates an example of a time monitoring table according to the embodiment of this invention. The table is composed of a start timer value after receiving a request and a response waiting table after request relay transmission for each boot server or boot relay device. The response waiting table after request relay transmission is set only in the boot relay device. The start timer after receiving the request is meaningful for the boot server or boot relay device connected to the same network as the network computer that sends the boot request. In such a case, the value is set to 0.
[0065]
The boot server A in FIG. 13 (a) belongs to the same network as the network computer that sends the boot request, and is a single boot server. Ta = 0 is set.
[0066]
The boot relay X in FIG. 13B is on the same network as the boot server A, and Tx = 3 seconds so that the boot server A operates for the first time when the boot server A fails and cannot send a boot response. When the response from the boot server A is not received even after this time has elapsed, the boot relay X monitors the request relay destination device name and the request relay transmission so as to relay the boot request to the boot server on another network. A post-request-relay response wait table with a response wait timer value as a pair is provided. Here, the boot server B on the network 1216 in FIG. 12 is set to the first priority order, and the response waiting timer value is set to Txb = 2 seconds. As the second priority device, the boot relay Y and the response waiting timer value Txy = 10 seconds are set. That is, it means that the boot request is first relayed and transmitted to the boot server B, and when there is no response after 2 seconds, the boot request is relayed to the boot relay Y. Here, if there is no response after waiting for Txy = 10 seconds, it means that all boot servers at the relay destination are faulty.
[0067]
In FIG. 13C, when a boot request is relayed from the boot relay X, the boot relay Y has a start timer value Ty = 0 after receiving the request so that the relay processing is immediately started. Similarly, the relay destination device name and the response wait timer value are set in the response wait table after request relay transmission. For boot server C, Tyc = 2 seconds, boot server. For D, Tyd = 5 seconds is set. By setting in this way, the boot request of the network computer can be used for boot processing on the boot server on the network that is connected via the boot relay X and the boot relay Y and separated by multiple stages. it can.
[0068]
The operation of the network computer boot server selection system set as described with reference to FIGS. 12 and 13 will be described below along the time axis according to the operation explanatory diagram of the embodiment of the present invention shown in FIG.
[0069]
FIG. 14 shows devices connected to the networks (1), (2), (3), and (4) on the horizontal axis, that is, a network computer that transmits a boot request, a boot server, and a boot relay. The vertical axis indicates the time elapsed in seconds with the time point when the network computer NC-a issues a request being 00. However, this explanatory diagram is for explaining the order of events that occur, and the scale has no meaning. Further, although the time is shown in seconds, it shows a number for explanation, and it is in accordance with the example illustrated in the table of FIG. 13 and does not represent a practically ideal value.
[0070]
Based on the values in the time monitoring table in FIG. 13, the events on the network having the configuration in FIG. 12 will be described in order with reference to FIG.
[0071]
At time = 00, the network computer NC-a sends a boot request to the network (1) in a broadcast format. The boot server BS-A and the boot relay BR-X connected to the same network receive this boot request. At this time, BS-A sets Ta = 0, starts the timer, and immediately times out. However, the boot response cannot be returned for some reason. When receiving a request, BR-X on the same network sets Tx = 3 and starts a timer to monitor and wait for a response from a boot server on the same network.
[0072]
When time = 03, BR-X times out (Tx = 3). In other words, the boot server on the same network as the network computer that issued the request does not respond, so that it is necessary to request the boot processing to a boot server on another network.
[0073]
The boot relay device BR-X searches the response waiting table TBL-X after the request relay transmission set for itself and relays the request from the network computer to the first priority device, the boot server BS-B. send. A response waiting timer value Txb = 2 for monitoring a boot response to the boot request transmitted at the same time is set to start the timer and wait for a response.
[0074]
The request transmitted through the relay is sent to BS-B of network (2) and received. However, this also elapses in a state where a response cannot be returned due to a failure.
[0075]
When time = 05, that is, when the set BR-X timer times out with Txb = 2, BR-X is the boot relay of the next priority in table TBL-X, BR-Y on network (3) Relay requests to. At this time, the timer value Txy = 10 is set to monitor the time and wait for a response. Since the boot server on the network {circle around (2)} also failed to respond to booting, the operation proceeds to a relay operation to a boot server on another network.
[0076]
Similarly to the reception of the request, the boot relay BR-Y searches the table TBL-Y and first relays the request to the boot server BS-C in the order of priority. The monitoring timer waits for a response with Tyc = 2.
[0077]
It is assumed that the transmitted request is received by the boot server BS-C on the same network as BR-Y but cannot respond.
[0078]
When time = 07 and the timer of the boot relay device BR-Y times out with Tyc = 2, the boot relay device BR-Y searches for the next device in the table and makes a request to the boot server BS-D on the network (4). Is relayed and sent. The boot relay device BR-Y sets Tyd = 5 in the timer and waits for a response.
[0079]
This time, the boot server BS-D functions normally and returns a boot response when receiving the request. The response is received by the boot relay device BR-Y that relayed the request, the timer for monitoring the response is reset, and relayed sequentially to transmit the response to the request source. The boot relay device BR-X also resets the timer when receiving the response.
[0080]
The network computer NC-a that has received the response performs a boot process with the boot server BS-D on the network {circle around (4)} that is the source of the response. As a result, even when the boot servers BS-A, BS-B, and BS-C assumed here cannot return a response, the boot relay devices BR-X and BR-Y relay to another network. It is shown that the boot server BS-D can be selected to perform the boot process.
[0081]
【The invention's effect】
As is apparent from the above description, according to the present invention, when a plurality of boot servers are installed on the same network as the network computer that makes a boot request, the use priority can be easily set, and the boot server can be easily managed. A network computer system that is resistant to server failure by being able to relay boot requests between networks using a boot relay device and by enabling multiple boot server operations including boot servers on other networks. There is an effect that can be easily realized at low cost.
[0082]
In addition, there is also an effect that it is possible to realize a construction of a network computer system with a reduced cost in which boot processing of a network computer on a network having no boot server is performed by a boot server on another network.
[Brief description of the drawings]
FIG. 1 is a block diagram of the present invention.
FIG. 2 is an explanatory diagram of a boot server selection system.
FIG. 3 is an explanatory diagram of the operation of the boot server (claim 2).
FIG. 4 is a flowchart of the operation of the boot server (claim 2).
FIG. 5 is an operation explanatory diagram of a boot server (claim 3).
FIG. 6 is a flowchart of the operation of the boot server (claim 3).
FIG. 7 is an explanatory diagram of a boot relay device.
FIG. 8 is an explanatory diagram of the operation of the boot relay device (claim 4).
FIG. 9 is a flowchart of the operation of the boot relay device (claim 4).
FIG. 10 is an explanatory diagram of the operation of the boot relay device (claim 5).
FIG. 11 is an operation flowchart of the boot relay device (claim 5);
FIG. 12 is a configuration diagram of an embodiment of the present invention.
FIG. 13 is an explanatory diagram of an example of a time monitoring table according to the embodiment of this invention;
FIG. 14 is an explanatory diagram of an operation example of the embodiment of the present invention.
FIG. 15 is an operation explanatory diagram of a conventional boot server selection system.
[Explanation of symbols]
10 Boot server
11 Boot request receiving means
12 hour passage detection means
13 Boot response sending means
14 Boot response receiving means
20 Network computer
21 Boot request sending means
22 Boot response receiving means
30 Boot relay device
31 Boot request receiving means
32 hour passage detection means
33 Boot response receiving means
34 Boot request relay means
35 Device-specific response waiting time storage means
36 Relay order setting means

Claims (7)

To one or more boot servers that perform boot processing in response to boot requests from network computers on the network,
Boot request receiving means for receiving a boot request from a network computer;
A time elapse detecting means for detecting elapse of a preset time to be different for each boot server ;
A boot response sending means for sending a boot response when the time passage detecting means activated after receiving the boot request detects the passage of time;
A boot server selection system characterized in that a boot server that responds first executes a boot process of a network computer. In a boot server selection system for selecting a boot server that executes a boot process of a network computer from one or more boot servers,
A boot server installed on the same network as the network computer,
Boot request receiving means for receiving a boot request from a network computer;
A time elapse detecting means for detecting elapse of a preset time to be different for each boot server after receiving the boot request;
A boot response sending means for sending a boot response when the time passage detecting means detects the passage of time;
A boot server comprising: A boot response receiving means for receiving a boot response transmitted from another boot server installed on the same network as the network computer and storing the received response is provided.
3. The boot server according to claim 2, wherein the boot response transmitting means suppresses the transmission of the boot response when the boot response receiving means stores that the boot response has been received. In a boot server selection system for selecting a boot server that executes a boot process of a network computer from one or more boot servers,
A boot relay device that relays a network computer boot request to another network,
Boot request receiving means for receiving a boot request from a network computer;
A time elapse detecting means for detecting elapse of a preset time;
A boot response receiving means for receiving a boot response transmitted from the boot server and storing the received response;
Boot request relay means for relaying a boot request to a boot server or boot relay device on another network that is set in advance as a relay destination device,
The time elapse detecting means activated after receiving the boot request detects the elapse of time, and when the reception of the boot response is not stored, the boot request relay means relays the boot request to another network. A boot relay device. Device-specific response waiting for storing boot request relay selection priority order of one or more boot servers or boot relay devices on other networks and boot response waiting time for monitoring the boot response after boot request relaying correspondingly Time storage means;
One or more boot servers or boot relay devices stored in the device-specific response waiting time storage means are set as relay destination devices in the order of selection priority for boot request relaying, and the response waiting time stored correspondingly is detected as time passage detecting means. Relay order setting means for setting the relay order of boot requests by setting to
The boot request relay means relays the boot request to the boot server or the boot relay device set by the relay order setting means,
5. The boot relay device according to claim 4, wherein the time elapse detecting means detects elapse of time and activates the boot request relay means again when the reception of the boot response is not stored. In a boot server selection system for selecting a boot server that executes a boot process of a network computer from one or more boot servers,
A boot server program installed on the same network as the network computer,
Boot request receiving means for receiving a boot request from a network computer;
A time elapse detecting means for detecting elapse of a preset time so as to be different for each boot server after receiving the boot request;
A boot response sending means for sending a boot response when the time passage detecting means detects the passage of time;
A computer-readable recording medium in which a program for functioning as a computer is recorded. In a boot server selection system for selecting a boot server that executes a boot process of a network computer from one or more boot servers, a program for a boot relay device that relays a boot request of a network computer to another network,
Boot request receiving means for receiving a boot request from a network computer;
Time elapse detecting means for detecting elapse of a preset time,
A boot response receiving means for receiving a boot response transmitted from the boot server and storing the received response;
A boot request relay means for relaying a boot request to a boot server or boot relay device on another network set in advance as a relay destination device;
The time elapse detecting means activated after receiving the boot request detects the elapse of time, and when the reception of the boot response is not stored, the boot request relay means relays the boot request to another network. A computer-readable recording medium on which the program is recorded.

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