KR20220107775A - Apparatus and method for preventing bootstorm in No-HDD service - Google Patents

Abstract

Disclosed is an apparatus and a method for preventing a boot storm from occurring by appropriately distributing simultaneous access requests from multiple users in consideration of the data capacity of a central infrastructure in providing a No-HDD service. According to an embodiment, the apparatus for providing a no-hard (No-HDD) service to a plurality of user terminals without a disk comprises: a pre-boot group creation unit for creating a pre-boot group for each time zone for the plurality of user terminals based on available resources; an image allocator unit for allocating a booting image to each user terminal and storing the booting image of each user terminal in a storage unit; and a remote booting unit for remotely booting by transmitting the booting image to at least one user terminal belonging to the pre-booting group for each time slot.

Description

Apparatus and method for preventing bootstorm in No-HDD service

The present invention relates to an apparatus and method for a no-hard service, and more particularly, to an apparatus and method for preventing a boot storm.

DaaS (Desktop as a Service) is a service that allows users to access and use their computer from a remote location regardless of location. Such DaaS includes a Virtual Desktop Infrastructure (VDI) method and a No-HDD method depending on the provision method. The VDI service is a service that runs a virtual desktop instance by driving a virtual machine through a hypervisor on the host server, accesses the virtual machine from a remote client, and receives the screen of the virtual machine to stream. That is, all computing operations are performed on the host server, and the remote client receives and processes only the computing screen. The no-hard service is a method in which a physical disk such as a computer's hard disk is centralized in a central server with only computer peripherals such as computing devices, monitors, and keyboards in the user's personal space, that is, the client.

In the case of the no-hard method, the initial construction cost is low and management is easy because it provides computing functions based on the cloud environment. Because of these characteristics, a number of banks, corporations, and public institutions are currently adopting the no-hard method for the purpose of providing work computers. However, when the no-hard method is used for business purposes, the nature of the business computer causes a large number of employees to boot the computer at the same time during work hours. There is a problem that (Boot Storm) occurs. To date, various solutions have been proposed to solve the bootstorm issue, but there are disadvantages in terms of cost or performance.

The present invention provides an apparatus and method for preventing a bootstorm from occurring by appropriately distributing simultaneous access requests of multiple users in consideration of the data capacity of a central infrastructure in providing a no-HDD service but it has a purpose.

According to an embodiment, an apparatus for providing a No-HDD service to a plurality of user terminals without a disk includes generating a pre-boot group for each time period for the plurality of user terminals based on available resources. pre-boot group creation unit; an image allocator for allocating a boot image to each user terminal and storing the boot image of each user terminal in a storage unit; and a remote booting unit for remote booting by transmitting the booting image to at least one user terminal belonging to the pre-booting group for each time period.

The pre-boot group generation unit may calculate the maximum number of acceptable user terminals using the total network bandwidth and the network bandwidth required for booting one user terminal, and create a pre-boot group based on the maximum number of user terminals. have.

The pre-boot group generator may create a pre-boot group such that the number of user terminals in each pre-boot group is equal to or less than the maximum number of user terminals.

The pre-boot group generator may calculate the maximum number of acceptable user terminals by adding a buffer value to a network bandwidth required for booting the one user terminal.

The pre-boot group generator may calculate a boot-up time required for each user terminal in the pre-boot group for each pre-boot group, and set a pre-boot time period for each pre-boot group based on the calculation time.

The pre-boot group generator may set a pre-boot time period based on a boot time of a user terminal having the longest boot time in each pre-boot group.

The pre-boot group generation unit may set the pre-boot time period by further considering a buffer time to a boot time of the user terminal having the longest boot time.

The image allocating unit allocates a disk drive image to each user terminal and stores the disk drive image of each user terminal in the storage unit, wherein the device is a user terminal for which remote booting is completed by the remote booting unit. It may further include a service providing unit for transmitting the image.

A method of providing a no-HDD service from a central server to a plurality of user terminals without a disk according to an embodiment is a method of providing a pre-boot group for each time period for the plurality of user terminals based on available resources. generating; allocating a boot image to each user terminal and storing the boot image of each user terminal in a storage unit; and transmitting the booting image to at least one user terminal belonging to the pre-booting group for each time period to remotely boot the booting image.

In the step of creating the pre-boot group, the maximum number of acceptable user terminals is calculated using the total network bandwidth and the network bandwidth required for booting one user terminal, and a pre-boot group is formed based on the maximum number of user terminals. can create

The generating of the pre-boot group may include creating the pre-boot group such that the number of user terminals in each pre-boot group is equal to or less than the maximum number of user terminals.

The generating of the pre-boot group may include calculating the maximum number of acceptable user terminals by adding a buffer value to a network bandwidth required for booting the one user terminal.

The generating of the pre-boot group may include calculating a booting time required for each user terminal in the pre-boot group for each pre-boot group, and setting a pre-boot time period for each pre-boot group based on the calculation.

In the step of creating the pre-boot group, the pre-boot time period may be set based on a boot-up time of a user terminal having the longest boot-up time in each pre-boot group.

In the step of creating the pre-boot group, the pre-boot time period may be set by further considering a buffer time to a boot-up time of the user terminal having the longest boot-up time.

The method includes: allocating a disk drive image to each user terminal and storing the disk drive image of each user terminal in the storage unit; The method may further include transmitting the disk drive image to the user terminal on which the remote booting has been completed.

According to the present invention, in providing a no-hard service, simultaneous multiple connections of users can be distributed, thereby reducing the load on a central server that provides a no-hard service, and preventing an exception from this, and the access of user terminals time can be reduced.

According to the present invention, in providing a no-hard service, it is possible to provide an optimal service while reducing costs because a separate infrastructure expansion for solving the boot storm is not required.

1 is a diagram illustrating a no-hard service system according to an embodiment of the present invention.
2 is a diagram showing the configuration of a central server according to an embodiment of the present invention.
3 is a flowchart illustrating a method of preventing a bootstorm in a no-HDD service according to an embodiment of the present invention.

The above-described objects, features, and advantages will become more apparent through the following detailed description in relation to the accompanying drawings, and accordingly, those of ordinary skill in the art to which the present invention pertains can easily implement the technical idea of the present invention. There will be. In addition, in the description of the present invention, when it is determined that a detailed description of a known technology related to the present invention may unnecessarily obscure the gist of the present invention, the detailed description thereof will be omitted. Hereinafter, a preferred embodiment according to the present invention will be described in detail with reference to the accompanying drawings.

1 is a view showing a no-hard service system according to an embodiment of the present invention. Referring to FIG. 1 , the no-hard service system according to this embodiment includes a central server 110 , a plurality of user terminals 130 and and a network 150 connecting the central server 110 and the plurality of user terminals 130 .

The user terminal 130 is a arithmetic device without a physical disk, and includes a central processing unit (CPU), a graphic controller, and an input/output (I/O) device, and the input/output (I/O) device is a serial port It may include, but is not limited to, a controller, a parallel port controller, a USB controller, a keyboard, and a mouse. The CPU is coupled to system memory including dynamic random access memory (DRAM) and may include non-volatile memory such as programmable read only memory (PROM) or flash memory. The user terminal 130 without a physical disk may be referred to as a diskless user terminal or a no-hard user terminal.

When the user terminal 130 receives a signal for remote booting (eg, Wake On Lan (WOL)) from the central server 110 through the network 150, the user terminal 130 automatically turns on the power, and PXE ( Pre-boot eXecution Environment) requests booting data to the central server 110 according to the booting order, and completes booting by receiving a boot image and system data from the central server 110 . When booting is completed, the disk drive image allocated from the central server 110 is mounted on the user terminal 130 .

The central server 110 is a device that includes a mass storage device, such as one or more physical disks, and provides a virtual disk drive for a plurality of user terminals 130 without a physical disk to provide a computing environment. The central server 110 includes a NIC, a mass storage device, a CPU, an optical drive, and an input/output (I/O) device. The NIC provides an interface to the network 150 . The mass storage device may be configured as one or more RAID arrays or may include one or more hard disk drives operating independently. Alternatively, the mass storage device may be implemented using a storage area network (SAN) or network attached storage (NAS) subsystem.

The central server 110 creates pre-boot groups in order to properly distribute the load according to the simultaneous access requests of the user terminals 130 , that is, to prevent a boot storm, and a user belonging to the pre-boot groups For the terminals 130 , booting is performed in advance before the corresponding user terminals 130 connect. Accordingly, the bootstorm is prevented by properly distributing the connections of the user terminals 130 . This will be described in more detail below with reference to the drawings.

The network 150 refers to a connection structure capable of exchanging information between nodes such as terminals and servers, and includes a local area network (LAN), a wide area network (WAN), and the Internet. (WWW: World Wide Web), wired and wireless data networks, telephone networks, wired and wireless television networks, and the like. Examples of wireless data communication networks include 3G, 4G, 5G, 3rd Generation Partnership Project (3GPP), Long Term Evolution (LTE), World Interoperability for Microwave Access (WIMAX), Wi-Fi, Bluetooth communication, infrared communication, ultrasound communication, Visible Light Communication (VLC), LiFi, and the like, but are not limited thereto.

2 is a diagram showing the configuration of a central server according to an embodiment of the present invention. Referring to FIG. 2 , the central server 110 according to the present embodiment includes a pre-boot group creation unit 210 , an image allocator 220 , a remote boot unit 230 , a service provider 240 , and a storage unit. 250 , which may be implemented as a program, stored in a memory, and executed by at least one processor, or may be implemented as a combination of software and hardware.

The pre-boot group generator 210 creates pre-boot groups for performing pre-booting for each of the plurality of user terminals 130 irrespective of the user terminal 130's request. The pre-boot group generator 210 may create pre-boot groups based on available resources of the central server 110 and set a boot time period for each pre-boot group.

The pre-boot group generator 210 calculates the maximum number of acceptable user terminals based on the available resources of the central server 110 and the time required for booting each user terminal 130 , and then Based on the maximum number of user terminals and the booting time required for each user terminal, pre-boot groups are created, and a booting time period of each pre-boot group is set. Here, the usable resources include a network bandwidth required for booting one user terminal and a total network bandwidth of the central server 110 .

The pre-boot group generation unit 210 calculates the maximum number of user terminals that can be accommodated in the central server 110 by using the total network bandwidth of the central server 110 and the network bandwidth required for booting one user terminal 130 . Calculate. If this is expressed as an equation, it is as follows (Equation 1).

(Equation 1)

Maximum number of user terminals that can be accommodated =

Total network bandwidth of central server/1 network bandwidth required for booting of one user terminal

The maximum number of acceptable user terminals calculated by Equation 1 above means the maximum number of user terminals that can be simultaneously processed in parallel by the central server 110 . Accordingly, the pre-boot group generator 210 sets the number of user terminals belonging to each pre-boot group within the maximum number of acceptable user terminals calculated by Equation 1 above. Preferably, in order to prepare for the case where any user terminal 130 not belonging to the pre-boot group boots while performing the pre-boot for the pre-boot group, the number of user terminals in each pre-boot group is It is preferable to set less than the number of acceptable maximum user terminals calculated by (Equation 1). To this end, by adding a buffer value to the network bandwidth required for booting of one user terminal substituted into the denominator of the right term of Equation 1 above, the number of the maximum allowable user terminals can be calculated to be small. For example, when the maximum number of simultaneously accommodated user terminals of the central server 110 is 70, a plurality of pre-boot groups may be created and then 65 user terminals may be allocated to each pre-boot group.

When the pre-boot groups are determined, the pre-boot group generator 210 sets a pre-boot time period for each pre-boot group. First, the pre-boot group generator 210 calculates a time required for booting each user terminal 130 for each pre-boot group. The time required for booting of the user terminal 130 (ie, the time required for booting) is calculated by the following (Equation 2).

(Equation 2)

boot time =

Total amount of data generated during booting of one user terminal/1 network bandwidth required for booting of one user terminal

For example, based on Windows 10, the total amount of data generated during booting of one user terminal 130 is about 1083 MB. When the network bandwidth required for booting of the specific user terminal 130 is 18 MB/s, the booting time of the corresponding user terminal 130 is about 60 seconds (1083/18).

The pre-boot group generator 210 calculates the booting time required for each user terminal 130 for each pre-boot group, and then, based on the user terminal 130 having the longest booting time for each pre-boot group. Set the pre-boot time zone of the pre-boot group. For example, if the number of user terminals 130 in the pre-boot group A is 70, and the booting time of the user terminal 130 having the longest booting time among them is 1 minute and 30 seconds, the buffer is set to 1 minute and 30 seconds. By adding the time (eg, 30 seconds), 8:40 to 8:42 is set as the pre-boot time of the corresponding pre-boot group A. Here, it is described as adding the buffer time, but is not limited thereto, and the pre-boot time period may be set without considering the buffer time.

The pre-boot group generation unit 210 stores information of each generated pre-boot group in the storage unit 250 . The pre-boot group information includes identification information of the user terminal 130 belonging to each pre-boot group and a pre-boot time period of each pre-boot group.

Referring back to FIG. 2 , the image allocator 220 allocates a boot image and a disk drive image to each user terminal 130 . Here, the boot image is an ISO image that is transmitted to the remote user terminal 130 so that the user terminal 130 can perform a booting operation, and the disk drive image is a disk drive image in which an operating system and various programs are installed. . Preferably, the image allocator 220 creates a master disk drive image and then allocates the copied disk drive image to each user terminal 130 . The image allocator 220 matches and stores the boot image and disk drive image allocated to each user terminal 130 in the storage 250 together with identification information of each user terminal 130 .

The remote booting unit 230 remotely boots the user terminals 130 of each prebooting group based on the information of each prebooting group stored in the storage 250 at a specified prebooting time period. Specifically, the remote booting unit 230 turns on the power of each user terminal 130 using a Wake On Lan (WOL) function, and for each turned on user terminal 130 , a Pre-boot eXecution Environment (PXE) ) to boot. The remote booting unit 230 searches the storage unit 250 for a booting image corresponding to the user terminal 130 and transmits the booting image and system data to the user terminal 130 .

For example, the pre-boot time zone for pre-boot group A is 8:40 to 8:42, the pre-boot time for pre-boot group B is from 8:42 to 8:45, and 70 When the user terminals 130 are allocated, at 8:40, 70 user terminals 130 belonging to the pre-booting group A are simultaneously remotely booted, and at 8:42, 70 user terminals belonging to the pre-booting group B are remotely booted. (130) at the same time remote boot. Therefore, if the present invention is applied in a company, the user terminals 130 of the employees are in a booted state before the employees in the company go to work.

The service providing unit 240 provides a no-hard service to the user terminal 130 successfully booted by the remote booting unit 230 , that is, the service providing unit 240 , the booting successful user terminal 130 . The disk drive image of the corresponding user terminal 130 stored in the storage unit 250 is transmitted to be mounted on the corresponding user terminal 130 . Accordingly, the user can perform tasks using the operating system and application programs as if there is a physical disk in his or her user terminal 130 . When the operation is terminated by the user terminal 130 , the service providing unit 240 updates the disk drive image reflecting the operation data to the storage unit 250 so that the existing operation is maintained when the user reconnects later. do.

3 is a flowchart illustrating a method of preventing a bootstorm in a no-HDD service according to an embodiment of the present invention.

Referring to FIG. 3 , in step S301 , the central server 110 accommodates the central server 110 using the entire network bandwidth of the central server 110 and the network bandwidth required for booting one user terminal 130 . Calculate the maximum possible number of user terminals. That is, the maximum number of user terminals that can be accommodated is calculated by Equation 1 above. The maximum number of user terminals that can be accommodated means the maximum number of user terminals that can be simultaneously processed in parallel by the central server 110 .

In one embodiment, the central server 110 may provide the maximum number of acceptable users in case any user terminal 130 not belonging to the pre-boot group boots while performing the pre-boot on the pre-boot group. As the number of terminals, it is preferable to set it to be smaller than the actual number of acceptable maximum user terminals calculated by Equation 1 above. To this end, by adding a buffer value to the network bandwidth required for booting of one user terminal substituted into the denominator of the right term of Equation 1 above, the number of the maximum allowable user terminals can be calculated to be small.

In step S302, the central server 110 creates a pre-boot group based on the number of acceptable maximum user terminals calculated in step S301. The central server 110 creates the pre-boot group so that the number of user terminals in the pre-boot group is less than or equal to the maximum number of user terminals that can be accommodated. The central server 110 may create a plurality of pre-boot groups. The central server 110 matches information of the pre-boot group, for example, group identification information and identification information of each user terminal 130 , and stores the matching information in the storage unit 250 .

In step S303 , the central server 110 calculates a time required for booting each user terminal 130 (ie, a boot demand time) for each pre-boot group. The boot-up time required for the user terminal 130 is calculated by Equation 2 above. For example, based on Windows 10, the total amount of data generated during booting of one user terminal 130 is about 1083 MB. When the network bandwidth required for booting of the specific user terminal 130 is 18 MB/s, the booting time of the corresponding user terminal 130 is about 60 seconds (1083/18).

In step S304, the central server 110 sets a pre-boot time period of each pre-boot group created in step S302 based on the boot-up time required for each user terminal 130 calculated in step S303. For example, if the number of user terminals 130 in the pre-boot group A is 70, and the booting time of the user terminal 130 having the longest booting time among them is 1 minute and 30 seconds, the buffer is set to 1 minute and 30 seconds. By adding the time (eg, 30 seconds), 8:40 to 8:42 is set as the pre-boot time of the corresponding pre-boot group A. Here, it is described as adding the buffer time, but is not limited thereto, and the pre-boot time period may be set without considering the buffer time. The central server 110 stores the pre-boot time information of the pre-boot group in the storage unit 250 .

In step S305, the central server 110 allocates a boot image and a disk drive image to each user terminal 130 belonging to each pre-boot group. Here, the boot image is an ISO image that is transmitted to the remote user terminal 130 so that the user terminal 130 can perform a booting operation, and the disk drive image is a disk drive image in which an operating system and various programs are installed. . Preferably, the central server 110 creates a master disk drive image and then allocates the copied disk drive image to each user terminal 130 . The central server 110 matches and stores the boot image and the disk drive image allocated to each user terminal 130 in the storage unit 250 together with the identification information of each user terminal 130 .

In step S306, the central server 110 determines whether the pre-boot time has arrived. The central server 110 may determine whether the pre-boot time has arrived based on the pre-boot time information of each pre-boot group stored in the storage unit 250 .

When the pre-boot time of the specific pre-boot group arrives, in step S307, the central server 110 remotely boots each user terminal 130 of the specific pre-boot group. Specifically, the central server 110 turns on the power of each user terminal 130 using a Wake On Lan (WOL) function, and PXE (Pre-boot eXecution Environment) for each user terminal 130 that is powered on perform boot. The central server 110 searches the storage unit 250 for a booting image corresponding to the user terminal 130 and transmits the booting image and system data to the user terminal 130 .

After completing the remote booting of a specific pre-boot group, in step S308, the central server 110 checks whether the remote booting of all pre-boot groups is completed, and if there are remaining pre-boot groups to perform pre-booting, step S308 Returning to S306, the process of checking whether the pre-boot time has arrived, and steps S307 and S308 are repeatedly performed. When remote booting of all of the pre-boot groups is completed, the central server 110 ends the pre-booting operation. This pre-booting operation may be performed once a day, every day.

After the remote booting is completed, the central server 110 inquires the disk drive image assigned to each user terminal 130 from the storage unit 250 and transmits it. Accordingly, the disk drive image is mounted on the corresponding user terminal 130 , and the user can perform an operation using the operating system and the application program as if there is a physical disk in the user terminal 130 .

In the embodiment with reference to FIGS. 1 to 3 above, it has been described that users directly physically use the user terminal 130 as an example. That is, the diskless user terminal 130 is provided for each employee in the company, and before the user goes to work, the user terminal 130 of each user is pre-booted, and the user goes to work and separates the user terminal ( 130), you can work immediately without booting. However, it is not limited to this embodiment, and the user accesses the user terminal 130 using TeamViewer or a remote desktop protocol using a computing device such as a personal computer or notebook computer in another remote location, and , it is also possible to receive a screen image from the user terminal 130 to control the user terminal 130 remotely.

While this specification contains many features, such features should not be construed as limiting the scope of the invention or the claims. Also, features described in individual embodiments herein may be implemented in combination in a single embodiment. Conversely, various features described herein in a single embodiment may be implemented in various embodiments individually, or may be implemented in appropriate combination.

Although acts are described in a particular order in the drawings, it should not be understood that such acts are performed in the particular order as shown, or that all of the described acts are performed in a continuous order, or to obtain a desired result. . Multitasking and parallel processing may be advantageous in certain circumstances. In addition, it should be understood that the division of various system components in the above-described embodiments does not require such division in all embodiments. The program components and systems described above may generally be implemented as a package in a single software product or multiple software products.

The method of the present invention as described above may be implemented as a program and stored in a computer-readable form in a recording medium (CD-ROM, RAM, ROM, floppy disk, hard disk, magneto-optical disk, etc.). Since this process can be easily performed by a person of ordinary skill in the art to which the present invention pertains, it will not be described in detail any longer.

The present invention described above, for those of ordinary skill in the art to which the present invention pertains, various substitutions, modifications and changes are possible without departing from the technical spirit of the present invention. It is not limited by the drawings.

110: central server
130: user terminal
150: network
210: pre-boot group creation unit
220: image allocation unit
230: remote boot unit
240: service provider
250: storage

Claims (17)

In the device for providing a no-hard (No-HDD) service to a plurality of user terminals without a disk,
a pre-boot group generator for generating a pre-boot group for each time zone for the plurality of user terminals based on available resources;
an image allocator for allocating a booting image to each user terminal and storing the booting image of each user terminal in a storage unit; and
and a remote booting unit configured to remotely boot by transmitting the booting image to at least one user terminal belonging to the pre-booting group for each time period. According to claim 1,
The pre-boot group creation unit,
An apparatus comprising: calculating the maximum number of acceptable user terminals using the total network bandwidth and the network bandwidth required for booting one user terminal; and creating a pre-boot group based on the maximum number of user terminals. 3. The method of claim 2,
The pre-boot group creation unit,
The apparatus of claim 1, wherein the pre-boot group is created such that the number of user terminals in each pre-boot group is equal to or less than the maximum number of user terminals. 3. The method of claim 2,
The pre-boot group creation unit,
and calculating the maximum number of acceptable user terminals by adding a buffer value to a network bandwidth required for booting the one user terminal. According to claim 1,
The pre-boot group creation unit,
A device, characterized in that for each pre-boot group, a time required for booting each user terminal in the pre-boot group is calculated, and a pre-boot time period of each pre-boot group is set based on the calculation. 6. The method of claim 5,
The pre-boot group creation unit,
A device characterized in that the pre-boot time period is set based on the boot-up time of a user terminal having the longest boot-up time in each pre-boot group. 7. The method of claim 6,
The pre-boot group creation unit,
A device characterized in that the pre-boot time period is set by further considering the buffer time to the booting time of the user terminal having the longest booting time. According to claim 1,
The image allocator,
Allocating a disk drive image to each user terminal and storing the disk drive image of each user terminal in the storage unit,
The device is
The apparatus of claim 1, further comprising a service providing unit for transmitting the disk drive image to a user terminal on which remote booting has been completed by the remote booting unit. In the method of providing a no-HDD service to a plurality of user terminals without a disk in a central server,
creating a pre-boot group for each time zone for the plurality of user terminals based on available resources;
allocating a boot image to each user terminal and storing the boot image of each user terminal in a storage unit; and
and transmitting the booting image to at least one user terminal belonging to the pre-booting group for each time period and remotely booting the booting image. 10. The method of claim 9,
The step of creating the pre-boot group includes:
A method, comprising: calculating the maximum number of acceptable user terminals using the total network bandwidth and the network bandwidth required for booting one user terminal, and creating a pre-boot group based on the maximum number of user terminals. 11. The method of claim 10,
The step of creating the pre-boot group includes:
A method, characterized in that the pre-boot group is created such that the number of user terminals in each pre-boot group is equal to or less than the maximum number of user terminals. 11. The method of claim 10,
The step of creating the pre-boot group includes:
The method according to claim 1, wherein the maximum number of acceptable user terminals is calculated by adding a buffer value to the network bandwidth required for booting the one user terminal. 10. The method of claim 9,
The step of creating the pre-boot group includes:
A method comprising calculating a booting time required for each user terminal in the pre-boot group for each pre-boot group, and setting a pre-boot time period for each pre-boot group based on the calculation. 14. The method of claim 13,
The step of creating the pre-boot group includes:
A method characterized in that the pre-boot time period is set based on the boot-up time of a user terminal having the longest boot-up time in each pre-boot group. 15. The method of claim 14,
The step of creating the pre-boot group includes:
A method characterized in that the pre-boot time zone is set by further considering the buffer time to the boot time of the user terminal having the longest boot time. 10. The method of claim 9,
allocating a disk drive image to each user terminal and storing the disk drive image of each user terminal in the storage unit; and
The method further comprising the step of transmitting the disk drive image to the user terminal on which the remote booting has been completed. A computer program stored in a computer-readable recording medium as a computer program for executing the method according to any one of claims 9 to 16 through a computer system.

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