JP2009223467A - Server device, client device, server base computing system, and program - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To achieve the high speed operation of display in a client device by optimizing the data quantity of picture data to be created by a server device by using a program and to be transmitted to a client device by reducing the data quantity without losing visibility when the quality of communication is unsatisfactory in a server base computing system. <P>SOLUTION: The quality of communication is determined, and the performance mode of a program is changed based on the quality of communication, and when the quality of communication is satisfactory, the picture data of a display format suitable for the quality of communication are generated so that a display mode with a large data quantity is adopted when the quality of communication is satisfactory, and that the display mode with a small data quantity is adopted when the quality of communication is unsatisfactory. Thus, the high speed operation of display is achieved by optimizing the data quantity to be transmitted. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  In the present invention, an execution result of an application program executed by an operation instruction from a client device in a server device under an SBC (Server Based Computing) environment is connected to the network via the network. The present invention relates to a server device, a client device, a remote connection system, and a program that can be displayed on the client device.

  In the server-based computing system, the server device executes a program for the client device to create display data, and sends this to the client device. In the client device, operation information such as a user's key and mouse device is sent to the server device via the network, and the display data for the client device created on the server device side is received and displayed. The client device only needs to include an input device such as a network device, a display device, a mouse device, or a keyboard. Since no data is stored in the client device, a storage device such as a hard disk is basically unnecessary. Is not executed, the processing load required for the client device is light.

  However, when transmitting the display data for the client device created on the server device side, there is a problem that if the amount of display data is large, the communication time becomes long and it takes time to display.

  Further, even when the display data is frequently updated, it is necessary to transmit the updated display data every time the display data is updated. Therefore, there is a problem that the communication time becomes long and it takes time until the display data is displayed.

  In order to shorten the communication time when transmitting the display data, the display data is cached in the RAM of the client device, and when the same display data as the cached display data is displayed, the display data is not transmitted. In some cases, a method is used. However, a cache memory is required, and a load on the CPU for managing the cache is also applied. Also, it is generally difficult to increase the cache hit rate.

  There is a method of compressing and transmitting the display data, but if the display data compression rate is increased, the screen displayed on the client becomes unnecessarily rough. Also, if you use a lot of toolbars or detailed icons, or if you use a program that uses a lot of animated animations, you cannot increase the compression rate of the display data so much. There is a problem that it cannot be reduced.

  In addition, the server device first transmits the image data of the updated area as low-quality image data, and then transmits the image data as high-quality image data again to the client device, thereby speeding up the apparent display. Techniques for realizing it are disclosed. (For example, refer to Patent Document 1.)

JP 2006-246153 A

  In the method of Patent Document 1, the server device transmits the image data of the updated area with low image quality first, and then transmits the image data to the client device with high image quality again, so that the apparent display speed is high. Has been realized. Therefore, the time from the start of transmission to the end of transmission is not shortened, and there is a problem that the image quality of the screen data transmitted first is not good.

  The object of the present invention is to optimize the amount of screen data created by a server device by a program and transmitted to a client device by reducing the amount of screen data without losing visibility when the communication quality is poor. It is to realize high-speed display.

  The server device according to claim 1 is a server device that operates a program based on a service request from a client device via a network and transmits screen data corresponding to the service request to the client device. The operation data receiving means for receiving operation data from the client apparatus, the execution mode receiving means for receiving instruction data of the execution mode for changing the execution contents of the program from the client apparatus, and the delay state of communication with the client apparatus Communication quality determining means for determining communication quality, execution mode setting means for setting an execution mode of a program based on the determined communication quality or instruction data of the execution mode from the client device, and the set execution Run the program according to the mode And program executing means for generating data, is characterized by and a screen data transmission unit that transmits the screen data to the client device.

  According to a second aspect of the present invention, the server device operates according to the execution mode so as to change a display mode when the program is executed according to a large amount of data for display.

  The server apparatus according to claim 3 is characterized in that the quality of the communication includes quality due to a difference in transmission media such as a wired LAN and a wireless LAN.

  5. The client device according to claim 4, wherein the client device makes a service request to a server device connected via a network, and receives screen data in accordance with an operation of a program corresponding to the service request. Operation data transmitting means for transmitting to the server apparatus, execution mode transmitting means for transmitting execution mode instruction data for changing the execution contents of the program to the server apparatus, and screen data for receiving screen data from the server apparatus And receiving means.

  The client device according to claim 5 is characterized in that, according to the execution mode, the display mode when the program is executed is instructed to change depending on whether the data amount for display is large or small.

  According to a sixth aspect of the present invention, there is provided a server-based computing system comprising: a client device that makes a service request to a server device that operates a program; and a server device that operates a program based on a service request from the client device. In the server-based computing system configured to be mutually connectable via the server, the server device receives operation data from the client device and execution for changing the execution contents of the program from the client device Execution mode reception means for receiving mode instruction data, communication quality determination means for determining communication quality according to a delay state of communication with the client apparatus, and the determined communication quality or the execution from the client apparatus Mode Execution mode setting means for setting the execution mode of the program according to the display data, program execution means for generating the screen data by executing the program according to the set execution mode, and screen data for transmitting the screen data to the client device Transmission means, and the client device transmits operation data to the server device, operation data transmission means for transmitting operation data to the server device, and execution mode transmission for transmitting execution mode instruction data for changing the execution contents of the program to the server device. Means, and screen data receiving means for receiving screen data from the server device.

  8. The server device program according to claim 7, wherein the server device computer receives operation data receiving means for receiving operation data from the client device, and execution mode instruction data for changing execution contents of the program from the client device. Execution mode receiving means, communication quality determining means for determining communication quality according to a delay state of communication with the client apparatus, execution of a program based on the determined communication quality or the execution mode instruction data from the client apparatus An execution mode setting means for setting a mode, a program execution means for generating screen data by executing a program according to the set execution mode, and a screen data transmission means for transmitting the screen data to the client device. It is a feature.

  The program of the client device according to claim 8, wherein the computer of the client device transmits operation data transmitting means for transmitting operation data to the server device, and execution mode instruction data for changing execution contents of the program to the server device. It is characterized by functioning as an execution mode transmitting means for performing screen data receiving means for receiving screen data from the server device.

  According to the present invention, since the execution mode of the program is changed depending on the communication quality, the program screen can be displayed with a sufficient response speed without impairing the visibility of the user of the client device even when the communication quality is poor. . Further, since the user can set the execution mode of the program at an arbitrary timing, the screen data in a format that meets the user's request can be changed at an arbitrary timing.

Embodiments of the present invention will be described below with reference to the drawings.
First, the configuration in the present embodiment will be described.
FIG. 1 is a block diagram showing the overall configuration of a server-based computing system according to an embodiment of the present invention.

  This server-based computing system includes a server device 1 and a plurality of client devices 2 connected on a network 3 composed of a LAN (Local Area Network) or a WAN (Wide Area Network). The client device 2 is also called a thin client.

  The server device 1 has a plurality of programs such as a document creation processing program, a spreadsheet processing program, a presentation material creation program, a mail processing program, an Internet connection processing program, and a Web browser, and is a client device connected to the server device 1 2 is started in response to an operation input (input event) signal from 2 and the process is executed.

  In this server apparatus 1, the screen data for display output generated on the terminal frame buffer 14 a, which will be described later, with the execution of the program according to the operation input signal from the client apparatus 2 is the client apparatus 2 that is the access source. Sent to.

In the client device 2, the screen data transferred from the server device 1 is expanded in the frame buffer 25 and displayed on the display unit.
That is, each client device 2 in this server-based computing system has an input function corresponding to a user operation such as a keyboard and a mouse and an output function to a display unit as main functions, and at least the server device 1 has It does not have any function to execute various programs or data file management function.

FIG. 2 is a block diagram illustrating a configuration of main parts of the server device 1 according to the present embodiment.
The server device 1 includes a CPU 11 as a computer, and a ROM 13, a RAM 14, a frame buffer RAM 15, and a display device 16 are connected to the CPU 11 via a bus 12. The RAM 14 includes a terminal frame buffer 14a, an execution mode setting table A14b, and an execution mode setting table B14c.

  Further, an input device 17 such as a keyboard and a mouse, an external storage device 18 such as a hard disk, and a communication I / F (interface) 19 with the client device 2 are connected to the CPU 11 via the bus 12.

  The CPU 11 controls the operation of each part of the circuit by using the RAM 14 as a working memory according to a system control program or various programs stored in the ROM 13 in advance, via a key input signal from the input device 17 or a communication I / F 19. The various programs are started and executed in response to a processing command signal corresponding to a user operation (input event) from the client apparatus 2 received.

  In this server device 1, various data generated according to a program that is activated and executed in response to an input event signal from the client device 2 is stored in the external storage device 18 in association with the user ID, for example. The display screen data is generated using the terminal frame buffer 14a in the RAM 14, and is transferred from the communication I / F 19 to the client device 2 for display output.

  Note that screen data to be displayed on the display device 16 of the server device 1 itself is generated on the frame buffer RAM 15.

FIG. 3 is a block diagram illustrating a configuration of main parts of the client device 2 according to the present embodiment.
The client apparatus 2 includes a CPU 21 as a computer, and a ROM 23, a RAM 24, and a frame buffer RAM 25 are connected to the CPU 21 via a bus 22. The screen data written in the frame buffer RAM 25 is output to the display device 26 and displayed.

  Further, an input device 27 such as a keyboard, a mouse, a microphone, and an optical sensor, an external storage device 28 such as a flash memory, and a communication I / F (interface) 29 with the server device 1 are connected to the CPU 21 via the bus 22. Is done.

  The CPU 21 controls the operation of each part of the circuit using the RAM 24 as a working memory in accordance with a system control program stored in advance in the ROM 23, and is a server received via a key input signal from the input device 27 or a communication I / F 29. The system control program is activated and executed in response to a program response signal, screen data, etc. from the apparatus 1.

  In the client device 2, various data generated by executing the program in the server device 1 is appropriately written and stored in the external storage device 28. The received display screen data is written in the frame buffer RAM 25 and displayed on the display device 26.

Next, data used in the present embodiment will be described.
FIG. 4 is a diagram illustrating an example of the execution mode setting table A14b stored in the RAM 14 of the server device 1. The execution mode setting table A14b is a table set for switching the execution mode of the program in accordance with the communication quality.

  The execution mode setting table A14b includes a "program" indicating the name of the program, a "communication quality" indicating the communication quality level, an "execution mode" indicating the type of execution mode, and a "display" indicating a display format corresponding to the execution mode. ”, Each item of“ execution parameter ”indicating a method of delivering an execution parameter to be passed when the program is executed.

  In the example of FIG. 4, there are three levels of communication quality: “good”, “normal”, and “bad”. There are three types of execution modes: “mode 1”, “mode 2”, and “mode 3”. There are three types of display modes corresponding to the execution mode: “display image”, “display only small image”, and “hide image” in the case of AP1, and “display icon” in the case of AP2. There are two types of “display text”.

  The execution parameter delivery method may indicate a file in which the execution parameters are stored, or may indicate an argument value when executing the program. The execution parameter delivery method is set to “path name 1” in mode 1, “path name 2” in mode 2, and “path name 3” in mode 3 for AP1. In the case of mode 1, "argument value 1" is set, in mode 2, "argument value 1", and in mode 3, "argument value 2" is set.

  In the execution mode setting table A14b, for example, the data on the first line has the program name “AP1”, the communication quality level “good”, the execution mode type “mode 1”, and the display format at this time is “ The “display image” and execution parameter delivery method indicates that the execution parameter exists at the location on the external storage device 18 described in “path name 1”.

  Next, FIG. 5 is a diagram illustrating an example of the execution mode setting table B14c stored in the RAM 14 of the server device 1. The execution mode setting table B14c is a table that is set to switch the execution mode of the program in accordance with the type of communication transmission medium.

  The execution mode setting table B14c is “program” indicating the name of the program, “transmission medium” indicating the type of communication transmission medium, “execution mode” indicating the type of execution mode, and “display mode corresponding to the execution mode”. “Display” and “Execution parameter” items indicating the delivery method of the execution parameter delivered when the program is executed.

  In the example of FIG. 5, there are four types of communication transmission media: “wired LAN”, “wireless LAN”, “mobile phone”, and “PHS”. There are three types of execution modes: “mode 1”, “mode 2”, and “mode 3”. There are three types of display modes corresponding to the execution mode: “display image”, “display only small image”, and “hide image” in the case of AP1, and “display icon” in the case of AP2. There are two types of “display text”.

  The execution parameter delivery method may indicate a file in which the execution parameters are stored, or may indicate an argument value when executing the program. The execution parameter delivery method is set to “path name 1” in mode 1, “path name 2” in mode 2, and “path name 3” in mode 3 for AP1. In the case of mode 1, "argument value 1" is set, in mode 2, "argument value 1", and in mode 3, "argument value 2" is set.

  In the execution mode setting table B14c, for example, the data in the fifth line includes the program name “AP2”, the communication transmission medium type “wired LAN”, and the execution mode type “mode 1”. Indicates that the icon is displayed, and the execution parameter delivery method indicates that the argument value for executing the program is described in “argument value 1”.

Next, screen data in this embodiment will be described.
FIG. 6 is a diagram illustrating an example of an execution mode setting screen displayed on the display device 26 of the client device 2. On the screen 31, when setting the execution mode, (1) the execution mode setting is not used, (2) the execution mode depends on the transmission medium, and (3) the execution mode depends on the communication quality ( An arbitrary item is selected from the selection items 1) to (3) by a check box on the left side.

Next, the operation of the client device 2 in this embodiment will be described.
FIG. 7 is a flowchart showing details of the execution mode instruction process executed in the client device 2. Before executing the program, the user looks at the screen 31 shown in FIG. 6 and instructs the execution mode of the program.

  First, in step C01, the screen 31 shown in FIG. The user designates an execution mode of the program by selecting an arbitrary item from the selection items (1) to (3) using a check box on the left side. As a result, the selected check box is changed from a white square to a black square and displayed. (Step C02).

  When the selected execution mode is (2) (step C03: (2)), since the execution mode depends on the transmission medium, the execution mode flag is set to (2) (step C04) and connected. The type of transmission medium being set is set (step C05).

  When the selected execution mode is (1) (step C03: (1)), the execution mode setting is not used, so the execution mode flag is set to (1) (step C06).

  When the selected execution mode is (3) (step C03: (3)), since the execution mode depends on the communication quality, the execution mode flag is set to (3) (step C07), and the communication quality is determined. The communication quality manager, which is a module for measuring, is activated (step C08).

  Next, data related to the execution mode of the selected program set in the previous steps C04 to C08 is transmitted to the server apparatus 1.

Next, the operation of the server device 1 in this embodiment will be described.
FIG. 8 is a flowchart showing details of the execution mode setting process executed in the server device 1. This is a process of receiving data related to the selected execution mode from the client device 2, determining the received execution mode, and starting the program according to the execution mode.

  First, in step S01, data related to the execution mode of the program selected by the user is received from the client device 2.

  When the received execution mode is (2) (step S02: (2)), since the execution mode depends on the transmission medium, the execution mode flag is set to (2) and the execution mode setting table B14c of FIG. (Step S03), and the program execution parameters are set according to the setting contents of the execution mode setting table B14c (step S04).

  If the received execution mode is (1) (step S02: (1)), the execution mode setting is not used, so the execution mode flag is set to (1) (step S05).

  When the received execution mode is (3) (step S02: (3)), since the execution mode depends on the communication quality, the execution mode flag is set to (3) to measure the communication quality. The communication quality manager, which is a module, is activated to measure the communication quality (step S06). After measuring the communication quality, the execution mode setting table A14b of FIG. 4 is referred to (step S07), and the program execution parameters are set according to the setting contents of the execution mode setting table A14b (step S08).

  Next, the program is started according to the execution parameters determined in accordance with the selected execution mode set in the previous steps S03 to S08 (step S09).

  The activated program is designed to change the display style according to the execution mode in advance. For example, in the case of AP1, the display mode is “display image” in mode 1, “display only small image” in mode 2, and “display non-image” in mode 3, and in the case of AP2, The mode is designed to be executed in two types of display modes: “display icon” in mode 1 or mode 2 and “display text” in mode 3.

  FIG. 9 is a flowchart showing details of a program execution process executed in the server device 1. Execution processing according to the execution mode after the program is started. Even if the execution mode is changed at any time during execution, the execution mode can be changed by detecting the setting change when the screen is updated. It has become.

  First, the execution mode to be executed in step A01 is determined.

  When the execution mode is (2) (step A01: (2)), a process of displaying in a display format corresponding to the mode 2 set in the execution mode setting table A14b of FIG. 4 or the execution mode setting table B14c of FIG. Is executed (step A02).

  When the execution mode is (1) (step A01: (1)), the display is performed in a display format corresponding to the mode 1 set in the execution mode setting table A14b of FIG. 4 or the execution mode setting table B14c of FIG. Is executed (step A03).

  When the execution mode is (3) (step A01: (3)), the display is performed in a display format corresponding to the mode 3 set in the execution mode setting table A14b of FIG. 4 or the execution mode setting table B14c of FIG. Is executed (step A04).

  Next, it is detected whether or not the data on the display screen has been updated during the process of displaying in the display format corresponding to the set mode (step A05). If the data on the display screen has been updated (step A06: Yes), the execution mode may have been changed, so the process returns to step A01 to determine the execution mode again.

  The operation of the communication quality manager, which is a module for measuring communication quality, activated in step C08 in FIG. 7 and step S06 in FIG. 8 will be described using sequence diagrams of the server apparatus 1 and the client apparatus 2. . The communication quality manager is incorporated in each of the server device 1 and the client device 2, and operates in cooperation with each other.

  FIG. 10 is a sequence diagram of the server device 1 and the client device 2 in the measurement of communication quality.

  First, in sequence M01, the client apparatus 2 requests the server apparatus 1 to start measurement of communication quality. In response to the request, server device 1 transmits measurement data to client device 2 (sequence M02).

  The client device 2 receives the measurement data, obtains the elapsed time from the time requested to start the measurement, and obtains the level of communication quality by obtaining the difference (delay time) from the reference elapsed time. The measured value shown is calculated (sequence M03).

  Next, the client apparatus 2 transmits a measured value indicating the calculated communication quality level to the server apparatus 1 (sequence M04).

  The server device 1 determines the communication quality of the execution mode setting table A14b in FIG. 4 or the execution mode setting table B14c in FIG. 5 from the measured value indicating the received communication quality level.

  The client device 2 waits for a predetermined time set in advance (sequence M04), and then returns to the sequence M01 and repeats measurement. In synchronization with the client device 2, the server device 1 also returns to the sequence M01 and repeats measurement.

  As described above, the communication quality is determined, and the program execution mode is changed according to the communication quality. When the communication quality is good, it is displayed in a display format with a large amount of data, and when the communication quality is poor, the data is displayed. By generating screen data in a display format that matches the quality of communication, such as displaying in a display format with a small amount, it is possible to optimize the amount of data to be transmitted and increase the display speed.

  In the embodiment described above, the level of communication quality is three levels of “good”, “normal”, and “bad”, but it may be more or less than three.

  In the embodiment, the types of execution modes are “mode 1”, “mode 2”, and “mode 3”, but may be more or less than three.

  In the above-described embodiment, the display mode corresponding to the execution mode is three types of “display image”, “display only small image”, and “hide image” in the case of AP1, and in the case of AP2, “ Although two types of “display icon” and “display text” are used, the content and type of the display style may be arbitrarily set according to the function of the program.

  In the above embodiment, the execution parameter delivery method indicates the file storing the execution parameters or the value of the argument when executing the program. However, if the program can be executed, another delivery method is adopted. May be.

  In the embodiment, when data is transmitted from the server apparatus 1 to the client apparatus 2, the data may be compressed on the server apparatus 1 side and the data received on the client apparatus 2 side may be expanded. Further, the data may be encrypted on the server device 1 side and the data received on the client device 2 side may be decrypted. Furthermore, data compression / decompression and data encryption / decryption may be combined.

  The processes of the server apparatus 1 and the client apparatus 2 described in the embodiment, that is, the processes shown in the flowcharts of FIGS. 7 to 9 are all stored in the external storage device 18 and the external storage device 28 as a computer-readable program. It is remembered. These programs may be stored in a recording medium such as a semiconductor memory (ROM, RAM, etc.), a magnetic disk (floppy (registered trademark) disk, hard disk, etc.), and an optical disk (CD-ROM, DVD, etc.). A part or all of the program may be stored in a recording medium provided in the server device 1 or the client device 2 and received and read via the network 3.

  The present invention is not limited to the embodiment described above, and can take various configurations or shapes without departing from the gist of the present invention.

1 is a block diagram showing the overall configuration of a server-based computing system according to an embodiment of the present invention. The block diagram which shows the principal part structure of the server apparatus 1 which concerns on this embodiment. The block diagram which shows the principal part structure of the client apparatus 2 which concerns on this embodiment. The figure which shows an example of execution mode setting table A14b memorize | stored in RAM14 of the server apparatus 1. FIG. The figure which shows an example of execution mode setting table B14c memorize | stored in RAM14 of the server apparatus 1. FIG. The figure which shows an example of the setting screen of the execution mode displayed on the display apparatus 26 of the client apparatus. 6 is a flowchart showing details of execution mode instruction processing executed in the client apparatus 2; 5 is a flowchart showing details of an execution mode setting process executed in the server device 1; 4 is a flowchart showing details of a program execution process executed in the server device 1; The sequence diagram of the server apparatus 1 and the client apparatus 2 in the measurement of communication quality.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Server apparatus 2 ... Client apparatus 3 ... Communication network 11, 21 ... CPU
12, 22 ... Bus 13, 23 ... ROM
14, 24 ... RAM
14a: Client frame buffer 14b: Execution mode setting table A
14c ... Execution mode setting table B
15, 25 ... Frame buffer RAM
16, 26 ... Display device 17, 27 ... Input device 18, 28 ... External storage device 19, 29 ... Communication I / F

Claims (8)

A server device that operates a program based on a service request from a client device via a network and transmits screen data corresponding to the service request to the client device,
Operation data receiving means for receiving operation data from the client device;
Execution mode receiving means for receiving execution mode instruction data for changing the execution contents of the program from the client device;
Communication quality determining means for determining communication quality according to a delay state of communication with the client device;
Execution mode setting means for setting the execution mode of the program based on the determined communication quality or the execution mode instruction data from the client device;
Program execution means for generating screen data by executing a program according to the set execution mode;
Screen data transmitting means for transmitting the screen data to the client device;
A server device comprising: According to the execution mode, an operation is performed to change a display mode when the program is executed by a large amount of data for display.
The server apparatus according to claim 1. The quality of communication includes quality due to a difference in transmission media such as wired LAN and wireless LAN.
The server apparatus according to claim 1. A client device that makes a service request to a server device connected via a network and receives screen data according to the operation of a program corresponding to the service request,
Operation data transmitting means for transmitting operation data to the server device;
Execution mode transmission means for transmitting execution mode instruction data for changing the execution content of the program to the server device;
Screen data receiving means for receiving screen data from the server device;
A client device comprising: The execution mode is instructed to change the display mode when the program is executed depending on the small amount of data for display.
The client device according to claim 4. A server-based computer configured such that a client device that makes a service request to a server device that operates a program and a server device that operates a program based on a service request from the client device can be connected to each other via a network. Operating system,
The server device
Operation data receiving means for receiving operation data from the client device;
Execution mode receiving means for receiving execution mode instruction data for changing the execution contents of the program from the client device;
Communication quality determining means for determining communication quality according to a delay state of communication with the client device;
Execution mode setting means for setting the execution mode of the program based on the determined communication quality or the execution mode instruction data from the client device;
Program execution means for generating screen data by executing a program according to the set execution mode;
Screen data transmitting means for transmitting the screen data to the client device;
With
The client device is
Operation data transmitting means for transmitting operation data to the server device;
Execution mode transmission means for transmitting execution mode instruction data for changing the execution content of the program to the server device;
Screen data receiving means for receiving screen data from the server device;
A server-based computing system comprising: The server device computer
Operation data receiving means for receiving operation data from the client device;
Execution mode receiving means for receiving execution mode instruction data for changing the execution contents of the program from the client device;
Communication quality determining means for determining communication quality according to a delay state of communication with the client device;
Execution mode setting means for setting the execution mode of the program according to the determined communication quality or the execution mode instruction data from the client device;
Program execution means for generating screen data by executing a program according to the set execution mode,
Screen data transmitting means for transmitting the screen data to the client device;
Program to function as. The client device computer
Operation data transmitting means for transmitting operation data to the server device;
Execution mode transmission means for transmitting execution mode instruction data for changing the execution content of the program to the server device;
Screen data receiving means for receiving screen data from the server device;
Program to function as.

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