JP4872934B2 - Computer system, client computer, OS termination method, and OS termination program - Google Patents

Description

  The present invention relates to a computer having a diagnostic processor connected to an external server via a network, and more particularly to processing when an OS running on the computer is terminated.

  In order to increase the reliability of the computer, there is a computer system in which each client computer is provided with a diagnostic processor, and information from the diagnostic processor is collected in a server to remotely monitor operations and facilitate management of a large number of computers. is there.

  The diagnostic processor is connected to devices such as a CPU, a main storage device, an input / output path, a control device, and the like constituting the client computer through a diagnostic path that is separate from a path used in normal processing of the client computer. The device status is monitored. Communication between the diagnostic processor and the server is performed in a diagnostic network that is different from the network (hereinafter referred to as the OS network) used in normal processing of the client computer.

  Each client computer includes a boot loader. The boot loader loads an OS running on the client computer into the main storage device and executes it on the CPU. The boot loader can also read and execute large-scale software such as the OS and applications from the server via the OS network. Further, the boot loader can reside in the main storage device even during execution of the OS, and can terminate the OS being executed on the CPU.

  At that time, the diagnostic processor monitors the status of software running on the CPU, and notifies the server of information about software stalls (hereinafter sometimes referred to as SW stalls) or device malfunctions via the diagnostic network. To do. Incidentally, a stall means that the execution of an instruction in the CPU is stopped due to a condition such as an instruction dependency.

  In addition, the following is a technical document related to computer status monitoring by a diagnostic processor. Patent Document 1 discloses a technique of storing a console message generated at the time of a failure as a file and transferring it by ftp. Patent Document 2 discloses a technique of substituting the operation with another SVP when an SVP fails. Patent Document 3 discloses a technique for selecting an optimum route for transmitting a message.

  Patent Documents 4 to 6 disclose examples of methods for changing a message output destination. Patent Document 7 discloses a technique in which, when a failure of a local console is found, the console is switched to another computer connected via a network to continue operation. Patent Document 8 discloses an example of a method for changing the input / output path of a computer.

JP 2001-243136 A JP 2004-341982 A JP 2006-333486 A Japanese Patent Laid-Open No. 06-161919 Japanese Patent Laid-Open No. 06-223018 Japanese Patent Application Laid-Open No. 07-219886 JP 11-338730 A Japanese Patent No. 2762453

  Now, consider a case where a boot loader resident in a main storage device terminates an OS read and executed from a server in a client computer having a diagnostic processor as described above. If the diagnostic processor is normal, a message indicating that the OS has been terminated, and if there is a malfunctioning device, information about the device is sent to the server via the diagnostic network and output to the server via the diagnostic network To do.

  However, if a failure occurs in the diagnostic processor, a message indicating that the OS has ended cannot be output to the server. For this reason, the process for terminating the OS stops there. In this case, not only the OS cannot be terminated, but also information about each device detected by the boot loader during the process of forcibly terminating the OS due to the occurrence of an abnormality is not output to the server. It will also be difficult.

  Incidentally, none of the above-mentioned Patent Documents 1 to 8 has a configuration that can be applied to the case where the OS is terminated by a client computer having a diagnostic processor to solve the above-described problems.

  An object of the present invention is to provide a computer system, a client computer, an OS termination method, and an OS termination program that enable a boot loader message to be output and an OS termination by the boot loader even when a diagnostic processor fails.

To achieve the above object, a computer system according to the present invention includes a CPU, a main storage device, a diagnostic processor, a client computer having an input / output path, a server, an OS network connecting the input / output path and the server, A computer system having a diagnostic network that connects a diagnostic processor and a server and outputs an error message issued from the CPU to the server via the diagnostic processor , wherein the client computer initializes the input / output path A boot loader that later stores the OS on the main storage device and starts up on the CPU, and communication between the operating OS and the diagnostic processor to detect whether or not a fault has occurred in the diagnostic processor Diagnostic processor communication when ending OS and OS operation The diagnostic processor failure and having a OS shutdown processing unit for outputting the error message to the server through the OS network when it is detected that is caused by.

In order to achieve the above object, a client computer according to the present invention has a CPU, a main storage device, a diagnostic processor, and an input / output path. The OS operates and is connected to a server by an OS network connected to the input / output path. A client computer connected to the server by a diagnostic network connected to the diagnostic processor, and outputting an error message issued from the CPU to the server through the diagnostic processor and the diagnostic network, the input / output path being initialized A boot loader that later stores the OS on the main storage device and starts up on the CPU, and communication between the operating OS and the diagnostic processor to detect whether or not a fault has occurred in the diagnostic processor And the diagnostic processor when the OS operation is terminated. And an OS shutdown processing unit that outputs an error message to the server through the OS network when it is detected by the communication unit that a failure has occurred in the diagnostic processor.

In order to achieve the above object, an OS termination method according to the present invention includes a CPU, a main storage device, a diagnostic processor, and an input / output path, and includes a client computer on which the OS operates, a server, an input / output path, and a server. A computer system having an OS network to be connected and a diagnostic network that connects the diagnostic processor and the server and outputs an error message issued from the CPU to the server via the diagnostic processor , and terminates the OS. A method for storing an OS on a main storage device after initializing an input / output path and starting it on a CPU, and communicating between the OS and a diagnostic processor when the operation of the OS is terminated. A diagnostic processor communication process for detecting whether or not a fault has occurred in the diagnostic processor, and It is characterized by having an error message output step of outputting an error message to the server through the OS network when it is detected that the diagnosis processor has failed in step.

In order to achieve the above object, an OS termination program according to the present invention includes a CPU, a main storage device, a diagnostic processor, and an input / output path, and includes a client computer on which the OS operates, a server, an input / output path, and a server. A computer system having an OS network to be connected, and a diagnostic network that connects the diagnostic processor and the server and outputs an error message issued from the CPU to the server via the diagnostic processor . After the input / output path is initialized, the OS is stored in the main storage device and started on the CPU, and the OS and the diagnostic processor communicate with each other when the operation of the OS is terminated. Diagnostic processor communication processing that detects whether or not a failure has occurred and a diagnostic processor Characterized in that to execute the error message output process of outputting the error message to the server through the OS network when it is detected that fault diagnosis processor communication is occurring.

  Since the present invention is configured to output an error message to the server through the OS network if the diagnostic processor is stalled, the OS can be terminated by outputting an error message to the server. Thus, it is possible to provide a superior computer system, client computer, OS termination method, and OS termination program capable of outputting a boot loader message and allowing the boot loader to terminate the OS even when the diagnostic processor fails. it can.

[First Embodiment]
FIG. 1 is a block diagram showing a configuration of a computer system 100 and a client computer 1 included in the computer system 100 according to the first embodiment of the present invention. The client computer 1 includes a CPU 2, a main storage unit 3, a control unit 4, an input / output device 5, and a diagnostic processor 6. The diagnostic processor 6 has a nonvolatile memory 7 therein, and is connected to other devices in the client computer 1 via a diagnostic path 8 and is connected to a server 9 outside the client computer 1 via a diagnostic network 10.

  The input / output device 5 and the server 9 in the client computer 1 are connected via the OS network 11. The server 9 includes an external storage device 12 (HDD) that stores the OS 15b. On the other hand, a boot loader 14 b is stored in the nonvolatile memory 7 of the diagnostic processor 6. The boot loader 14b and the OS 15b are read into the CPU 2 and the main storage unit 3, and are executed as the boot loader 14 and the OS 15, respectively.

  When the client computer 1 is started, the boot loader 14 is first read. The boot loader 14 initializes and incorporates the input / output device 5, and software including the OS 15 b from the external storage device 12 of the server 9 via the OS network 11. The data necessary for the operation is read, and the read OS 15 is started. A message from the OS 15 is output to the console screen 13 on the server 9 via the OS network 11.

  FIG. 2 is a block diagram illustrating functions of the OS 15, the boot loader 14, and the diagnostic processor 6 that are executed on the CPU 2 disclosed in FIG. 1. In FIG. 2, various data including an instruction code group and a configuration management table 31 required when the OS 15 and the boot loader 14 are executed on the CPU 2 are stored in the main storage unit 3.

  During operation on the CPU 2, the OS 15 has a software (SW) stall monitoring timer reset function 211 and a configuration management function 212, and the boot loader 14 has an I / O initialization function 222, an OS load function 223, and a SW stall monitoring timer start. A function 224 and an OS shutdown function 225 that are implemented by the CPU include a communication function 221 with a diagnostic processor.

  The diagnostic processor 6 has a CPU communication function 61, a diagnostic path control function 62, a device access function 63, a SW stall monitoring timer 64, and a server communication function 65. The main processing contents of the OS 15 and the boot loader 14 other than those shown in FIG. 2 are well known to those skilled in the art and are not directly related to the present invention, so that they are not particularly mentioned.

  FIG. 3 is a flowchart showing the operation of the diagnostic processor 6 disclosed in FIGS. 1 and 2. The diagnostic processor 6 is activated when the client computer 1 is powered on, and waits for an operator's instruction to the client computer 1 while being in an operating state. After that, the diagnostic processor 6 operates according to an instruction from the operator when the processing (step S301) from the power-on of each device until each device becomes usable through initialization, initial diagnosis, and the like is completed. Start processing.

  The diagnostic processor 6 stores the instruction code group of the boot loader 14b stored in the nonvolatile memory 7 in the main storage unit 3 by the initial boot load (step S302), and then issues an interrupt to the CPU 2 (step S303). The boot loader 14 is activated. In the initial boot load of step S302, the diagnostic path control function 62 of the diagnostic processor 6 is used to access the designated address area of the main storage unit 3 from the diagnostic processor 6 and write data. In step S303, the CPU communication function 61 is used to interrupt the CPU via the diagnostic path 8.

  Thereafter, the diagnostic processor 6 waits for each processing request in order to perform processing according to the processing request (step S304). If the received processing request is a SW stall monitoring timer start request or a SW stall timer reset request, the SW stall monitoring timer 64 is started (step S305) and the SW stall is monitored while being updated.

  When the SW stall monitoring timer 64 has timed out (step S306), the system is forcibly terminated according to the judgment of the diagnostic processor 6 (step S307). ) Will continue.

  For example, when the diagnostic processor 6 accepts a data transmission request, the apparatus specified by the data transmission request is accessed via the diagnostic path 8 by the diagnostic path control function 62 (step S308), and the data is transmitted by the apparatus access function 63. Data designated by the sending request is read (step S309), and sent to the server 9 via the diagnostic network 10 by the server communication function 65 (step S310).

  FIG. 4 is a flowchart showing the operation of the CPU 2 disclosed in FIGS. 1 and 2. After the boot loader 14 is written in the designated address area of the main storage unit 3 by the diagnostic processor 6, each function shown in FIG. 2 starts to operate in response to a CPU interrupt by CPU communication (step S 303 in FIG. 3).

  When the boot loader 14 stored in the main storage unit 3 and stored in the diagnostic processor 6 is activated (step S401), the CPU 2 uses the I / O initialization function 222 to load an I / O path necessary for loading the OS 15 from the external storage device 12. The peripheral device is initialized and incorporated in the configuration managed by the software (step S402).

  When the I / O path and the peripheral device become usable, the CPU 2 writes the usable I / O path to the configuration management table 31 of the main storage unit 3 by the OS load function 223, and uses the usable I / O path. The OS 15b is read from the external recording device 12 to the main storage unit 3 (step S403), and the SW stall monitoring timer 64 is used to detect the stall of the OS 15 by the SW stall monitoring timer start function. Is instructed to the diagnostic processor 6 using the communication function 221 with the diagnostic processor (step S404, corresponding to steps S305 to 307 in FIG. 3), and the process is switched to pass control to the OS 15 (step S405). ).

  When the control unit 4 that has received the communication process executed on the CPU 2 determines that the transmission destination of the communication is the diagnostic processor 6, it notifies the diagnostic processor 6 of the content of the communication via the diagnostic path 8. The method is well known and will not be described in detail.

  In the operation of the OS 15 after the control is transferred by the process switching in step S405, the SW stall monitoring timer reset function 211 first resets the SW stall monitoring timer 64 (step S406), and thereafter, the diagnostic processor 6 detects the SW stall. Timer monitoring is continued so that the SW stall monitoring timer 64 is periodically reset (typically, one minute before SW stall detection is detected) (step S407). As a result, unless the SW stall occurs, the SW stall monitoring timer 64 does not time up and the OS 15 continues to operate.

  In the OS 15, if there are I / O paths and peripheral devices other than those initialized and incorporated by the boot loader 14, they are initialized by the configuration management function 212 and incorporated into the configuration managed by the software to update the configuration management table 31. (Step S408), and thereafter, processing such as activation and use of various applications is performed based on a request from the operator.

  Here, when the use of the OS environment is terminated by receiving an OS termination instruction from the operator (step S409), OS shutdown processing is started by the OS shutdown function 225 of the boot loader 14 (step S410).

  In the process by the boot loader 14, a message is displayed on the console screen 13 on the server 9 via the diagnosis processor 6 for the process progress or an abnormality detected during the process. However, if a failure occurs in the diagnostic processor 6, a message cannot be displayed on the console screen 13.

  Therefore, in the present embodiment, the boot loader 14 determines whether or not a failure has occurred in the diagnostic processor 6 (step S411). More specifically, it can be determined that a failure has occurred in the diagnostic processor 6 in the case where the communication function 221 with the diagnostic processor executed for displaying the above-mentioned message has not responded for a certain period of time.

  If it is determined that a failure has occurred, the OS shutdown function 225 of the boot loader 14 refers to the configuration management table 31 updated by the peripheral device incorporation processing in step S408 (step S412), and the I / O path used by the OS A message is output via (step S413). In this case, a message is output to the console screen 13 on the server 9 via the OS network 11. If no failure has occurred, a message is displayed on the console screen 13 on the server 9 via the diagnostic network 10 as usual (step S413).

  As described above, in the first embodiment described above, when it is determined that a failure has occurred in the diagnostic processor 6, the configuration management table 31 updated by the processing of the OS 15 is referred to and the peripherals incorporated in the OS 15. A message is output to the device (in this case, the console screen 13 on the server 9 via the OS network 11). Therefore, even when a failure occurs in the diagnostic processor 6, an error message from the boot loader 14 can be output to the console screen 13 on the server 9, and the shutdown of the OS 15 can be completed.

[Second Embodiment]
In the second embodiment of the present invention, the configuration of the apparatus is the same as that of the computer system 100 described with reference to FIGS. Further, the operation of the diagnostic processor 6 is the same as the operation shown in the flowchart of FIG. Accordingly, only the differences will be described here, and points not corresponding to the differences will not be described.

  FIG. 5 is a flowchart showing the operation of the CPU 2 according to the second embodiment of the present invention. FIG. 5 also includes many operations common to those in FIG. 4 according to the first embodiment of the present invention, and therefore common operations are denoted by the same reference numerals. 5 first performs the same operation as FIG. 4 until the operation of resetting the SW stall monitoring timer 64 in step S406. After step S406, the communication function 221 with the diagnostic processor includes an operation of monitoring whether or not there is a response from the diagnostic processor 6 (step S451).

  If there is a response from the diagnostic processor 6 in step S451, the process proceeds to monitoring until the SW stall monitoring timer 64 shown in step S407 is reset, and thereafter the same operation as in FIG. 4 is continued. If there is no response from the diagnostic processor 6 in step S451, it is determined that a failure has occurred in the diagnostic processor 6, and the process proceeds to OS shutdown processing in steps S410 to 413.

  With this configuration, the failure of the diagnostic processor 6 can be monitored during the operation of the OS 15, and the OS 15 can be promptly terminated when a failure occurs.

  In the first and second embodiments of the present invention described above, the boot loader 14 may be stored not in the nonvolatile memory 7 in the diagnostic processor 6 but in the external storage device 12 in the same manner as the OS 15. Good. In that case, when each device becomes usable after power-on (step S301), the boot loader 14 is sent from the server 9 to the diagnostic processor 6 as data in response to a file transfer request from the diagnostic processor 6 to the server 9, or the like. To.

[Third Embodiment]
In the third embodiment of the present invention, the configuration of the apparatus is the same as that of the computer system 100 described with reference to FIG. 1, but there is a difference in the configuration of functions executed there. FIG. 6 is a block diagram showing functions of the OS 15, boot loader 14, diagnostic processor 6, and server 9 executed on the CPU 2 in the computer system 100 according to the third embodiment of the present invention.

  In FIG. 6, the functions of the OS 15, the boot loader 14, and the diagnostic processor 6 are the same as those in the first and second embodiments of the present invention described in FIG. In addition to them, in the third embodiment of the present invention, the server 9 monitors the state of the diagnostic processor through periodic communication and detects a failure, and the OS notification function notifies the OS 15. 92.

  When the server 9 detects a failure of the diagnostic processor 6 by the diagnostic processor monitoring function 91, the OS notification function 92 notifies the OS 15 of the failure of the diagnostic processor 6. The processing executed on the CPU 2 is the same as the flowchart according to the second embodiment of the present invention described with reference to FIG. When a failure of the diagnostic processor 6 is notified from the server 9 by the OS notification function 92, processing when a failure occurs in the diagnostic processor 6 is performed in step S451.

  Accordingly, since there is no need to wait for a response from the diagnostic processor 6 in the client computer 1 in which the diagnostic processor 6 is in a failure state, the OS 15 can be terminated more quickly.

  In the embodiment described above, the OS 15 operating on the client computer 1 is read from the server 9 via the OS network 11 and activated, but the present invention is not limited to this embodiment. The OS 15 may be stored in the client computer 1, for example, or may be read from a server different from the server 9 having the console screen 13. Further, the OS 15 can be read from another computer or an external storage device connected by a network or interface different from either the diagnostic network 10 or the OS network 11.

  Although the present invention has been described with the specific embodiments shown in the drawings, the present invention is not limited to the embodiments shown in the drawings, and is known so far as long as the effects of the present invention are achieved. It goes without saying that any configuration can be adopted.

  It can be applied to a client computer equipped with a diagnostic processor. In particular, it is suitable for those that read and execute an OS from a server.

It is a block diagram which shows the structure of the computer system which concerns on the 1st Embodiment of this invention, and the client computer contained in this computer system. It is a block diagram which shows the function which OS and boot loader which are performed on CPU disclosed in FIG. 1, and a diagnostic processor have. It is a flowchart showing operation | movement of the diagnostic processor disclosed by FIG. 1 and FIG. It is a flowchart showing operation | movement of CPU disclosed in FIG. 1 and FIG. It is a flowchart showing operation | movement of CPU which concerns on the 2nd Embodiment of this invention. It is a block diagram which shows the function which OS and boot loader, diagnostic processor 6, and server 9 which are performed on CPU in the computer system concerning 3rd Embodiment have.

Explanation of symbols

1 Client computer 2 CPU
3 Main storage unit 4 Control unit 5 Input / output device 6 Diagnostic processor 7 Non-volatile memory 8 Diagnostic path 9 Server 10 Network for diagnosis 11 Network for OS 12 External storage device 13 Console screen 14, 14b Boot loader 15, 15b OS
31 Configuration Management Table 61 CPU Communication Function 62 Diagnostic Path Control Function 63 Device Access Function 64 SW Stall Monitoring Timer 65 Server Communication Function 91 Diagnostic Processor Monitoring Function 92 OS Notification Function 100 Computer System 211 SW Stall Monitoring Timer Reset Function 212 Configuration Management Function 222 I / O initialization function 223 OS load function 224 SW stall monitoring timer start function 225 OS shutdown function 221 Communication function with diagnostic processor

Claims (21)

A client computer having a CPU, a main storage device, a diagnostic processor, and an input / output path, on which an OS operates, a server, an OS network connecting the input / output path and the server, the diagnostic processor, and the server And a diagnostic network that outputs an error message issued from the CPU to the server via the diagnostic processor .
The client computer is
A boot loader that stores the OS on the main storage device after the input / output path is initialized and starts the CPU on the CPU;
A diagnostic processor communication unit that communicates between the operating OS and the diagnostic processor to detect whether or not a fault has occurred in the diagnostic processor;
An OS shutdown that outputs the error message to the server through the OS network when the diagnostic processor communication unit detects that a failure has occurred in the diagnostic processor communication unit when terminating the operation of the OS And a processing unit. The client computer has a configuration management table for storing a configuration for the OS to output the error message to the server through the OS network;
The computer system according to claim 1, wherein the OS shutdown processing unit outputs the error message to the server through the OS network with reference to the configuration stored in the configuration management table. . The server has an external storage device including an OS that runs on the client computer,
The computer system according to claim 2, wherein the boot loader reads the OS from the external storage device of the server and starts it on the CPU.   The computer system according to claim 2, wherein the boot loader is stored inside the diagnostic processor.   The computer system according to claim 2, wherein the boot loader is stored in the external storage device. The diagnostic processor has a monitoring timer for detecting whether software operating on the CPU is in a stalled state;
The computer system according to claim 2, wherein the OS includes a monitoring timer reset unit that periodically resets the monitoring timer.   3. The operation of the OS according to claim 2, wherein the diagnostic processor communication unit monitors whether or not there is a response from the diagnostic processor during the operation of the OS, and terminates the operation of the OS if there is no response from the diagnostic processor. The computer system described.   8. The computer according to claim 7, wherein the server monitors whether or not there is a response from the diagnostic processor during the operation of the OS, and terminates the operation of the OS if there is no response from the diagnostic processor. system. A CPU, a main storage device, a diagnostic processor, and an input / output path; the OS is operated; the OS is connected to the input / output path; the server is connected to the server; and the diagnostic network connected to the diagnostic processor A client computer connected to a server and outputting an error message issued from the CPU to the server through the diagnostic processor and the diagnostic network;
A boot loader that stores the OS on the main storage device after the input / output path is initialized and starts the CPU on the CPU;
A diagnostic processor communication unit that communicates between the operating OS and the diagnostic processor to detect whether or not a fault has occurred in the diagnostic processor;
An OS shutdown that outputs the error message to the server through the OS network when the diagnostic processor communication unit detects that a failure has occurred in the diagnostic processor communication unit when terminating the operation of the OS A client computer comprising: a processing unit. A configuration management table storing a configuration for the OS to output the error message to the server through the OS network;
10. The client computer according to claim 9, wherein the OS shutdown processing unit outputs the error message to the server through the OS network with reference to the configuration stored in the configuration management table. .   The client computer according to claim 10, wherein the boot loader reads the OS from the server and starts it on the CPU.   The client computer according to claim 10, wherein the boot loader is stored in the diagnostic processor.   The client computer according to claim 10, wherein the boot loader stored in the external storage device is read from the server through the OS network. The diagnostic processor has a monitoring timer for detecting whether software operating on the CPU is in a stalled state;
The client computer according to claim 10, wherein the OS includes a monitoring timer reset unit that periodically resets the monitoring timer.   11. The operation of the OS according to claim 10, wherein the diagnostic processor communication unit monitors whether or not there is a response from the diagnostic processor during the operation of the OS, and terminates the operation of the OS if there is no response from the diagnostic processor. The client computer described.   The client computer according to claim 15, wherein the operation of the OS is terminated when a signal indicating that there is no response from the diagnostic processor is received from the server during the operation of the OS. A client computer having a CPU, a main storage device, a diagnostic processor, and an input / output path, on which an OS operates, a server, an OS network connecting the input / output path and the server, the diagnostic processor, and the server And a diagnostic network for outputting an error message issued from the CPU to the server via the diagnostic processor, and terminating the OS.
An OS activation step of storing the OS on the main storage device after the input / output path is initialized and starting the CPU on the CPU;
A diagnostic processor communication step of performing communication between the OS and the diagnostic processor when the operation of the OS is terminated, and detecting whether or not a failure has occurred in the diagnostic processor;
An error message output step of outputting the error message to the server through the OS network when it is detected in the diagnostic processor communication step that a failure has occurred in the diagnostic processor. OS termination method. The OS startup step includes a configuration management table storage step for storing a configuration for the OS to output the error message to the server through the OS network,
The OS termination method according to claim 17, wherein the error message output step includes a configuration management table reference step for referring to the configuration stored in the configuration management table storage step.   19. The OS termination method according to claim 18, wherein the OS activation step reads the OS from the server and activates the OS on the CPU. A client computer having a CPU, a main storage device, a diagnostic processor, and an input / output path, on which an OS operates, a server, an OS network connecting the input / output path and the server, the diagnostic processor, and the server And a diagnostic network for outputting an error message issued from the CPU to the server via the diagnostic processor, and connecting the client computer to the client computer,
An OS activation process for storing the OS on the main storage device after the input / output path is initialized and starting the CPU on the CPU;
A diagnostic processor communication process for performing communication between the OS and the diagnostic processor when the operation of the OS is terminated, and detecting whether or not a failure has occurred in the diagnostic processor;
An error message output process for outputting the error message to the server through the OS network when it is detected in the diagnostic processor communication process that a failure has occurred in the diagnostic processor. OS termination program.   21. The OS termination program according to claim 20, wherein the OS activation process reads the OS from the server and activates the OS on the CPU.

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