Abstract:
A program execution service providing system can realize a system receiving specialized service adapted for request of each of users of services. The program execution service providing system includes a client connecting mechanism connecting a client to a server via a network, a program management mechanism reading program uploaded by the client and a program preliminarily prepared in the server, a program verification and conversion mechanism verifying that the read program satisfies security not affecting for the server or other program and converting adapting for execution by the server as required, a program execution control mechanism controlling for executing a program converted and managing the calculation resource to be used fairly among actuated programs, inter-program communication mechanism for mutual communication of a plurality of read programs and external device communication mechanism cooperating the program read by the program management mechanism and an external system of the server.

Description:
BACKGROUND OF THE INVENTION  
         [0001]    1. Field of the Invention  
           [0002]    The present invention relates generally to a program execution service providing system, a server, a program execution service providing method and a storage medium storing programs therefor. More particularly, the invention relates to a program execution service providing system executable of process desired by a user on a common server.  
           [0003]    2. Description of the Related Art  
           [0004]    In the recent years, various useful information and services are provided on a network. Particularly, huge number of services is currently provided in onerous or free by various business enterprises, organizations, individuals and so forth on World Wide Web (WWW). Many of those are premised in use of browser to permit receiving of service by direct operation by users.  
           [0005]    However, services basically provided on the network available for the users are those prepared by service providers. Therefore, it is not always possible to use services desired by the users.  
           [0006]    For example, in a technology disclosed in Japanese Unexamined Patent Publication No. Heisei 11 (1999)-345202, there has been proposed a method for varying services to be provided depending upon skill of the users. This is mere selection of preliminarily prepared services adapting to the users and is not make services which are not preliminarily prepared, available.  
           [0007]    On the other hand, in a technology disclosed in Japanese Unexamined Patent Publication No. Heisei 10 (1998)-260821, there has been proposed a method to permit users to select information contents to receive as services. However, even in this case, items available for selection are those preliminarily prepared by the service provider and services other than those preliminarily prepared by the service provider are not available at all.  
           [0008]    As a solution for inconvenience as set forth above, there has been proposed a method for customizing of services as requested by the user or a method for up loading programs realizing requested services on a server.  
           [0009]    For example, in a technology disclosed in Japanese Unexamined Patent Publication No. 2000-47912, there has been proposed a method of automatically generating a program for monitoring a log to transfer to the server. On the other hand, in a technology disclosed in Japanese Unexamined Patent Publication No. 2000-155743, there has been proposed a method for generating an agent for performing process of an event, in which an agent definition is transferred from a client to the server and the agent is generated in the server.  
           [0010]    However, these systems are limited to available function in monitoring and event processing and are not adapted for all of variety of services. On the other hand, since use by general public has not been considered, resource management function of the server has not been provided to cause make it impossible to prevent improper occupation of CPU (central processing unit) or memory resource of the server by evil user, bug in the program or other causes and to prevent improper or illegal process and so forth.  
           [0011]    Furthermore, some of the service desired by the user cannot be satisfied by one time of service execution and require continue certain process for a given period. One example of such service is monitoring of variation of transaction price in the stock market, automatic transaction and so forth. However, general user is difficult to establish connection to the service through an always-on network for the reason of communication circuit, terminal or the like, to perform process. Therefore, there is a method to enable to provide service for standing in continuous process.  
           [0012]    For example, in U.S. Pat. No. 5,974,406, there has been proposed a system, in which the user issues a certain monitoring request to the server to shut-down connection, subsequently, the server stands in monitoring process to send a notice to the user through an appropriate means when a given condition is satisfied. On the other hand, even in a technology disclosed Japanese Unexamined Patent Publication No. 2000-155743, execution of monitoring process by server is enabled.  
           [0013]    However, in these systems, object of continuing process is limited to the monitoring process, and is difficult to apply processes other than monitoring. For example, upon performing not only monitoring of stock but also automatic transaction, necessary information required depending upon each individual process content, such as current shareholding, cash balance, trading history and so forth. However, in the foregoing existing technology, a function for holding such information has not been provided. In case of monitoring process, as long as monitoring algorithm is provided, executing condition information or the like for other process is not required. However, in typical continuous process as we as automatic transaction, it becomes necessary to hold executing condition of the process.  
           [0014]    As means for realizing holding of the executing condition, it becomes possible to hold the executing condition of single process by holding executing condition in the program per se. However, in this system, when the process includes interaction with the executing, condition of process executed outside of the server or other process, it is not possible to store the executing condition together with the condition of the counterpart of the interaction without discrepancy.  
           [0015]    For example, when a process to perform ordering of stock sends an order sheet to a security company outside of the server, unless the process for sending the order sheet and storing of executing condition is controlled to certainly executed sending of the order sheet and storing of the executing condition of the single process simultaneously, erroneous understanding is caused that the order sheet has not been sent in the process to cause doubling of order if the executing condition is not stored due to system failure or other cause in spite of the fact that the order sheet has been sent and system is re-booted. For avoiding such condition, it is required to cooperatively perform the communication process and storing of the executing condition. However, the system, in which the own executing condition is stored by the processing program per se, cannot realize this.  
           [0016]    On the other hand, while different from server operation through browser, as a technology for performing process desired by the user on other computer, there is a technology called as mobile agent. For example, in technologies disclosed in Japanese Unexamined Patent Publication No. Heisei 7 (1995)-182174 or Japanese Unexamined Patent Publication No. 2000-20487 and so forth, an object to be called as agent generated on certain computer and its definition program are moved to other computer designated by issuance of moving command with maintaining executing condition to enable continuation of execution of the process. Using this, an agent is generated in the terminal owned by the user and then is transferred to the server to execute the service to enable arbitrary service on the server.  
           [0017]    However, in these mobile agent technologies, there has not been provided a function for execution management by uploading only program from a remote client to the server. As a result, upon operating the server from the remote client to execute the desired process, it is inherent to activate the program on the side of the client and after activation, the activated program is moved to the server.  
           [0018]    In contrast to this, since dedicated execution environment has to be installed on both of the computers on the side from which the agent is moved and the side, to which the agent is moved, in the mobile agent, the user has to prepare these dedicated execution environments on the own terminal. On the other hand, moving process of the agent has to be performed by sending both of the object and the definition program at every occasion to make communication amount between the terminal and the server required for moving large.  
           [0019]    Furthermore, such mobile agent technology encounters a problem to cause difficulty in assuring security in both of the server and agent (M. S. Greenberg, J. C. Byington and D. G. Harper, “Mobile Agents and Security”, IEEE Communications Magazine, pp 76 to 85, July, 1998). Therefore, such mobile agent technology is difficult to use in actual system.  
           [0020]    On the other hand, in loading of the system to transferring and executing the program between different computers, such as uploading/downloading of the mobile agent or program and so forth, languages [such as Java (registered trademark of Sun Microsystems Inc. U.S.A.)] of an interpreter system (a system for executing necessary minimum source programs at every occasion) as one of execution types of the programs described by high level programming language, have been used widely.  
           [0021]    In such system, not only the program to be transferred, but also the program per se controlling execution of the transferred program is frequently described by Java language. The reason of such construction is that the program to be transferred can be described not relying on the architecture, and that the program per se for executing the transferred program can be described not relying of the architecture.  
           [0022]    In such construction, for efficient execution, the program executing the transferred program and the transferred program per se are frequently executed as the same program on a memory space. The reason is that execution speed of the transferred program can be maximized in this method.  
           [0023]    However, in loading the normal interpreter system which is not thought of execution of a plurality of programs in single memory space, a problem is encountered in that Kernel executed on the physically same memory space cannot appropriately perform protection of resource or fair assignment of the resource between logically plurality of programs to be executed on the physically same memory space. Robert Wahbe et al. “Efficient Software-Based Fault Isolation” (Proceeding of 14th ACM Symposium on Operating Systems Principles, pp 203 to 216, December 1993) discloses a method to perform program execution safely in the same memory space. However, in this method, only protection for illegal access of the memory is realized and no means is provided for fair distribution of the memory and calculation resource.  
           [0024]    In the conventional system set forth above, the system is not constructed for providing specialized service requested by each user of the service. Particularly, the conventional system has no realizing means by which, when the user desires execution of certain process, the desired process is freely expressed as program or request definition, the program or request definition is transferred to the server of the service provider through a general purpose interface, such as browser or the like for executing the process safely and at high speed on the server.  
           [0025]    Since the program uploading technology does not thought of common use of server by a plurality of users, there is no guarantee for security in execution. The mobile agent technology has no function for uploading the program to the server from the remote place or for managing execution. When the mobile agent function is used in place, since dedicated execution environment is required in the user terminal and the server, the service cannot be used unless preliminary preparation of the terminal. On the other hand, another problem is encountered in that the communication amount between the client and server is large and security cannot be ensured.  
           [0026]    On the other hand, in the conventional system, when the request of the user is continuous process requiring external communication and storing of the executing condition of the process, there is no means to realize such request. Also, since the automatic monitoring system is not thought of application other than monitoring, it is not possible to store the executing condition which is not required for monitoring. In the system for storing own executing condition by each individual processing program, and the process includes interaction of the executing conditions of outside of the server and other process, it is not possible to certainly store the conditions without discrepancy.  
           [0027]    Furthermore, when the program execution function is constructed on the interpreter for solving the foregoing problem, it is difficult to fair distribution of the resource or protection thereof between a plurality of programs to be executed and Kernel controlling their execution.  
         SUMMARY OF THE INVENTION  
         [0028]    The present invention has been worked out in view of the problems set forth above. It is therefore an object of the present invention to provide a program execution service providing system, a server, a method thereof and a storage medium storing the program, which can realize a system receiving specialized service adapted for request of each of users of services.  
           [0029]    Another object of the present invention is to provide a program execution service providing system, a server, a method thereof and a storage medium storing the program, which can certainly store the executing condition without discrepancy even when the process is continuous process requiring storing of the executing condition and includes interaction of outside of the system and other process.  
           [0030]    A further object of the present invention is to provide a program execution service providing system, a server, a method thereof and a storage medium storing the program, which can realize the system with fair distribution and protection of the resource on the existing interpreter system.  
           [0031]    A program execution service providing system, according to the present invention, comprises:  
           [0032]    a client connecting mechanism permitting a client to connect to a server via a network;  
           [0033]    a program management mechanism individually reading any one of a program uploaded by the client and a program preliminarily prepared in the server vis the client connectiong mechanism;  
           [0034]    a program verification and conversion mechanism verifying that the program read by the program management mechanism satisfies a nature of security not affecting for the server or other program and converting into a format adapted for execution by the server as required;  
           [0035]    a program execution control mechanism controlling at least executing a program converted by the program verification and conversion mechanism and managing the calculation resource to be used fairly among actuated programs;  
           [0036]    inter-program communication mechanism for mutual communication of a plurality of programs read by the program management mechanism; and  
           [0037]    external device communication mechanism cooperating the program read by the program management mechanism and an external system of the server.  
           [0038]    Another program execution service providing system according to the present invention, realizes the program and the server at least on a byte code interpreter as a single address space and the same program.  
           [0039]    A further program execution service providing system according to the present invention, further comprises program executing condition storage mechanism for storing executing condition of the actuated program in storage means at an appropriate timing during execution of the program.  
           [0040]    A server according to the present invention, comprises:  
           [0041]    a client connecting mechanism to be connected to a client via a network;  
           [0042]    a program management mechanism individually reading any one of a program uploaded by the client and a program preliminarily prepared in the own system;  
           [0043]    a program verification and conversion mechanism verifying that the program read by the program management mechanism satisfies a nature of security not affecting for own system or other program and converting into a format adapted for execution by the own system as required;  
           [0044]    a program execution control mechanism controlling at least executing a program converted by the program verification and conversion mechanism and managing the calculation resourde to be used fairly among actuated programs;  
           [0045]    inter-program communication mechanism for mutual communication of a plurality of programs read by the program management mechanism; and  
           [0046]    external device communication mechanism cooperating the program read by the program management mechanism and an external system of the own system.  
           [0047]    Another server, according to the present invention, realizes the program and the server at least on a byte code interpreter as a single address space and the same program.  
           [0048]    A further server according to the present invention, further comprises program executing condition storage mechanism for storing executing condition of the actuated program in storage means at an appropriate timing during execution of the program.  
           [0049]    A program execution service providing method, according to the present invention, comprises:  
           [0050]    first step of permitting a client to connect to a server via a network;  
           [0051]    second step of individually reading any one of a program uploaded by the client and a program preliminarily prepared in the server;  
           [0052]    third step of verifying that the read program satisfies a nature of security not affecting for the server or other program and converting into a format adapted for execution by the server as required;  
           [0053]    fourth step of controlling at least executing the read program and managing the calculation resaurce to be used fairly among actuated programs;  
           [0054]    fifth step of establishing mutual communication of a plurality of read programs; and  
           [0055]    sixth step of cooperating the read program and an external system connected to the server.  
           [0056]    Another program execution service providing method according to the present invention, realizes the program and the server at least on a byte code interpreter as a single address space and the same program.  
           [0057]    A further program execution service providing method according to the present invention, further comprises seventh step of storing executing condition of the actuated program in storage means at an appropriate timing during execution of the program.  
           [0058]    A storage medium storing a program of a program execution service providing method, according to the present invention, comprises:  
           [0059]    first process of permitting a client to connect to a server via a network;  
           [0060]    second process of individually reading any one of a program uploaded by the client and a program preliminarily prepared in the server;  
           [0061]    third process of verifying that the read program satisfies a nature of security not affecting for the server or other program and converting into a format adapted for execution by the server as required;  
           [0062]    fourth process of controlling at least executing the read program and managing the calculation resource to be used fairly among actuated programs;  
           [0063]    fifth process of establishing mutual communication of a plurality of read programs; and  
           [0064]    sixth process of cooperating the read program and an external system connected to the server.  
           [0065]    Another storage medium storing the program of the program execution service providing method, according to the present invention, realizes the program and the server at least on a byte code interpreter as a single address space and the same program.  
           [0066]    A further storage medium storing the program of the program execution service providing method, according to the present invention, further comprises the seventh process for storing executing condition of the actuated program in storage means at an appropriate timing during execution of the program.  
           [0067]    Namely, in the program execution service providing system according to the present invention, the agent server has the verification and conversion mechanism of the program which is uploaded to guarantee protection from the uploaded program, protection from the executing condition of other programs and from other executing conditions of the same program and proper distribution of the computer resource, such as CPU, memory and so forth.  
           [0068]    On the other hand, in the program execution service providing system according to the present invention, the executing condition of the program is managed by the server and the system has executing condition storage mechanism cooperated with the communication mechanism to store the executing condition in the external storage or the like at an appropriate timing for certainly enabling execution of the process requiring to store the executing condition.  
           [0069]    Furthermore, in the program execution service providing system, not only by actuating the program through the communication mechanism, by the user, but also by obtaining the result of execution of the past actuated program and the executing condition of the program on execution, arbitrary process desired by the user can be executed by the server and the user can operate the server.  
           [0070]    More particularly, the program execution service providing system according to the present invention has the agent server unit including the client communication mechanism, the user management mechanism, the program management mechanism, the program verification and conversion mechanism, the program execution control mechanism, the inter-program communication mechanism, the external device communication mechanism and the program executing condition storage mechanism.  
           [0071]    The user establishes connection with the server through the client communication mechanism and receives authentication of the user management mechanism. Then, the user can use other mechanism in the server via the client communication mechanism. When other mechanism is used, the connected user information is transferred to the mechanism to be used as user information.  
           [0072]    At first, the user uploads the program describing the desired process to the server via the client communication mechanism using the program management mechanism. The program management mechanism verifies the received program whether it contains secure code or not using the program verification and conversion mechanism, and in conjunction therewith, converts the received program into a format adapted for operation on the server. The program thus converted is stored in the external storage device.  
           [0073]    Subsequently, the user designates initiation of execution of the program to the program execution control mechanism through the client communication mechanism. The program execution control mechanism is responsive to designation to take out the designated program in converted form from the program management mechanism to actuate as a part of the function of the server and manages execution until the end of the program irrespective whether the user is connected through the client communication mechanism. On the other hand, the executing condition is stored in the memory or the external storage device at a proper timing by the program executing condition storage mechanism.  
           [0074]    The programs on execution communicate with executing condition of other program or outside of the server via the inter-program communication mechanism. When communication is caused, the executing condition storage mechanism stores the executing condition of the process together with communication content.  
           [0075]    The user also communicates with the program on execution through the client communication mechanism and the inter-program communication mechanism to obtain halfway condition of the execution and provide instruction for varying operation. On the other hand, the user establishes connection with the program executing condition control mechanism via the client communication mechanism to obtain a list of programs on execution and to stop program on execution.  
           [0076]    In the program execution service providing system, both of the server computer and the client computer are connected to the network to communication over the network. The agent server unit is operated on the server computer.  
           [0077]    With the construction set forth above, the program execution service providing system according to the present invention enables the user to upload the requesting process in a form of program (user program) to the server to control execution. Also, in the environment where the server of the shown system and the user program are operate as the same program, it becomes possible to execute the programs without mutually and adversely affecting with each other. Also, upon occurrence of failure during server operation and stoppage of the server, it becomes possible to continue execution of the user program without causing discrepancy after rebooting.  
           [0078]    When the user desires execution of certain single turn or continuous process, and respective desired process are freely expressed as program or request definition. Then, the program or request definition thus generated is transferred to the server of the service provider to make it possible to safely process on the server. Therefore, the system, on which the user of the service may receive the service, specialized for own request, can be realized.  
           [0079]    On the other hand, when the process is the continous process requiring storage of the executing condition and includes interaction with the outside of the system or other process, the executing condition can be certainly stored without discrepancy to realize the system with fair distribution and protection of the resource on the existing interpreter system. 
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0080]    The present invention will be understood more fully from the detailed description given hereinafter and from the accompanying drawings of the preferred embodiment of the present invention, which, however, should not be taken to be limitative to the invention, but are for explanation and understanding only.  
         [0081]    In the drawings:  
         [0082]    [0082]FIG. 1 is a block diagram showing a construction of an embodiment of an agent server system according to the present invention;  
         [0083]    [0083]FIG. 2 is a block diagram showing use mode of the embodiment of the agent server system according to the present invention;  
         [0084]    [0084]FIG. 3 is a block diagram showing a construction of the first embodiment of a program execution service providing system according to the present invention;  
         [0085]    [0085]FIG. 4 is an illustration showing an example of description of a program which can be uploaded by a user in one embodiment of the present invention;  
         [0086]    [0086]FIG. 5 is a flowchart showing operation of a client communication mechanism of FIG. 3;  
         [0087]    [0087]FIG. 6 is a flowchart showing operation of a client communication mechanism of FIG. 3;  
         [0088]    [0088]FIG. 7 is an illustration showing a construction of a user information table having a user management mechanism of FIG. 3;  
         [0089]    [0089]FIG. 8 is a flowchart showing operation of a program management mechanism of FIG. 3;  
         [0090]    [0090]FIG. 9 is an illustration showing a construction of a program table of FIG. 3;  
         [0091]    [0091]FIG. 10 is a flowchart showing operation of a program execution control mechanism of FIG. 3;  
         [0092]    [0092]FIG. 11 is an illustration showing a construction of a management table of a program on execution to be stored in the program execution control mechanism of FIG. 3;  
         [0093]    [0093]FIG. 12 is a block diagram showing a construction of a program executing condition of FIG. 3;  
         [0094]    [0094]FIG. 13 is an illustration showing a data structure of a program executing condition database managed by a program executing condition storing mechanism of FIG. 3;  
         [0095]    [0095]FIG. 14 is a flowchart showing operation of the program executing condition storing mechanism of FIG. 3;  
         [0096]    [0096]FIG. 15 is a block diagram showing a construction of an inter-program communication mechanism of FIG. 3;  
         [0097]    [0097]FIG. 16 is a flowchart showing operation of the inter-program communication mechanism of FIG. 3;  
         [0098]    [0098]FIG. 17 is a flowchart showing operation of a scheduler of FIG. 3;  
         [0099]    [0099]FIG. 18 is a flowchart showing operation upon actuation of the agent server system of FIG. 3;  
         [0100]    [0100]FIG. 19 is a flowchart showing operation of a program verification and conversion mechanism of FIG. 3;  
         [0101]    [0101]FIG. 20 is a flowchart showing operation of a program verification and conversion mechanism of FIG. 3;  
         [0102]    [0102]FIG. 21 is a flowchart showing operation of the second embodiment of a program management mechanism according to the present invention;  
         [0103]    [0103]FIG. 22 is a block diagram showing a construction of the fourth embodiment of the program execution service providing system according to the present invention;  
         [0104]    [0104]FIG. 23 is a block diagram showing a construction of the fifth embodiment of the program execution service providing system according to the present invention;  
         [0105]    [0105]FIG. 24 is an illustration of a data structure of an accounting database of FIG. 23;  
         [0106]    [0106]FIG. 25 is a flowchart showing operation of the program management mechanism of FIG. 23;  
         [0107]    [0107]FIG. 26 is a flowchart showing operation of a program execution control mechanism of FIG. 23;  
         [0108]    [0108]FIG. 27 is a flowchart showing operation of the scheduler of FIG. 23;  
         [0109]    [0109]FIG. 28 is a flowchart showing operation of the eighth embodiment of the scheduler according to the present invention;  
         [0110]    [0110]FIG. 29 is a flowchart showing operation of the eighth embodiment of the inter-program communication mechanism according to the present invention; and  
         [0111]    [0111]FIG. 30 is a block diagram of a use mode of the ninth embodiment of the agent server system according to the present invention. 
     
    
     DESCRIPTION OF THE PREFERRED EMBODIMENT  
       [0112]    The present invention will be discussed hereinafter in detail in terms of the preferred embodiments of the present invention with reference to the accompanying drawings. In the following description, numerous specific details are set forth in order to provide a thorough understanding of the present invention. It will be obvious, however, to those skilled in the art that the present invention may be practiced without these specific details. In other instance, well-known structure is not shown in detail in order to avoid unnecessary obscurity of the present invention.  
         [0113]    [0113]FIG. 1 is a block diagram showing a construction of an embodiment of an agent server system according to the present invention. In FIG. 1, the agent server system  1  includes a client communication mechanism  11 , a user management mechanism  12 , an external equipment communication mechanism  13 , a program management mechanism  14 , a program verification and conversion mechanism  15 , a program execution control mechanism  16 , an inter-program communication mechanism  17  and a program executing condition storage mechanism  18 .  
         [0114]    A user establishes connection with a server (not shown) through the client communication mechanism  11 . Upon authentication of the user management mechanism  12 , the user may use other mechanism in the server. When other mechanism is used, the connected user information is transferred to the mechanism to be used as user information.  
         [0115]    At first, the user uploads a program describing a desired process via the client communication mechanism  11  using the program management mechanism  14 , to the server. The program management mechanism  14  verifies the received program whether it contains safe code or not by the program verification and conversion mechanism  15 , and in conjunction therewith, converts the received program into a format appropriate for operation on the server to store in an external storage device (not shown).  
         [0116]    Subsequently, the user commands initiation of execution of the program to the program execution control mechanism  16  through the client communication mechanism  11 . The program execution control mechanism  16  is responsive to the command from the user to take out the converted program as designated from the program management mechanism  14  to actuate as a part of the function of the server and manages execution of the program to end irrespective whether the user is connected to the client communication mechanism  11  or not. On the other hand, the executing condition is stored in a memory (not shown) or the external storage device at an appropriate timing by the program executing condition storing mechanism  18 .  
         [0117]    The program on execution communicates with other program on execution or outside of server via the inter-program communication mechanism  17 . Upon occurrence of communication, the program executing condition storing mechanism  18  stores the executing condition of the process together with the communication content.  
         [0118]    The user also communicates with the program on execution via the client communication mechanism  11  and the inter-program communication mechanism  17  to obtain a condition in process of execution or to command for changing operation. On the other hand, the user establishes connection with the program execution control mechanism  16  via the client communication mechanism  11  to obtain a list of programs on execution and stop execution of the program.  
         [0119]    [0119]FIG. 2 is a block diagram showing use mode of the embodiment of agent server system  1  according to the present invention. In FIG. 2, a server computer  2  and a client computer  3  are both connected to a network  100  to communicate through the network  100 . The agent server system  1  operates on the server computer  2 .  
         [0120]    [0120]FIG. 3 is a block diagram showing a construction of the first embodiment of a program execution service providing system according to the present invention. In FIG. 3, the first embodiment of the program execution service providing system is constructed with the server computer  2  loaded the agent server system  1 , the client computer  3  loaded a general purpose Graphic User Interface (GUI) and an external equipment  4 .  
         [0121]    The agent server system  1  and an environment using the same is consisted of the server computer 2 connected to the network, the client computer  3  as terminal connected to the server computer  2  on the network to be used by the user, a general program execution platform (hereinafter referred as platform)  21  having an interpreter  21   a  and a library  21   b  executed on the server computer  2 , and a general purpose GUI  31  operated on the client computer  3 .  
         [0122]    Here, the preferred embodiment of the platform  21  is an execution environment of Java language as a language of interpreter system. The preferred embodiment of the general purpose GUI  31  is WWW (WorldWide Web) browser. In the following discussion, the execution environment of Java language is used.  
         [0123]    The agent server system  1  operates on the platform  21  on the server computer  2 . The agent server system  1  is constructed with the client communication mechanism  11 , the user management mechanism  12  including a user information table  23 , an external equipment communication mechanism  13 , the program management mechanism  14  including a program table  22 , the program verification and conversion mechanism  15 , the program execution control mechanism  16  having the scheduler  16   a  and a management table  16   b , an inter-program communication mechanism  17  and the program executing condition storage mechanism  18  connected to the program executing condition database  24  stored serialized program executing condition.  
         [0124]    In the shown embodiment, the program which can be uploaded by the user is not normal program but is described as group of execution units explicitly managed the executing condition by the program per se. The user program is called at an appropriate timing and in a given format by the server computer  2 . Each program performs fraction of process whenever it is called by the server computer  2 .  
         [0125]    Each of the actuated programs has own and distinct data region to progress execution of the program with appropriately making reference to data stored in each own data region. This data region becomes the program executing condition. The program to be executed is responsive to call from the server computer  2  to be required to complete own process within a relatively short period and to return the control to the server computer  2 .  
         [0126]    As set forth above, by restricting describing method of the program to be executed, it is advantageous to realize multi-process relatively easily. On the other hand, in this method, since it is not required to perform low level process, such as interrupt or complicate stacking process, it is suitable for mounting in Java language as the preferred embodiment of the present invention.  
         [0127]    On the other hand, the program which can be uploaded by the user, can call several instruction according to a format determined by the agent server system  1  when the program uses the function of agent server system  1 . Kinds of instructions are message sending, message reception, temporary interrupt of program execution and so forth.  
         [0128]    [0128]FIG. 4 is an illustration showing an example of description of the program which can be uploaded by the user in one embodiment of the present invention. FIG. 4 shows an example of description of the program by Java language as preferred embodiment of the present invention.  
         [0129]    A program A mounts a method run as common interface for programs which can be uploaded, to be called by the agent server system  1  and an instant parameter pc which is data to be managed by the program. One execution unit by the agent server system  1  corresponds to one call of run method.  
         [0130]    The agent server system  1  repeatedly calls the run method. The program varies operation from time to time depending upon the value of the parameter pc as called. An instance of User Program Sample class having the instant parameter pc becomes program executing condition.  
         [0131]    [0131]FIGS. 5 and 6 are flowcharts showing operation of the client communication mechanism  11  of FIG. 3. Operation of the client communication mechanism  11  will be discussed with reference to FIGS. 3, 5 and  6 .  
         [0132]    The client communication mechanism  11  waits for connection from the client computer  3  (step S 1  of FIG. 5). When connection with the client computer  3  is established, user authentication is performed (step S 2  of FIG. 5). When the user authentication is successful (step S 3  of FIG. 5), the client communication mechanism  11  is situated into a state of waiting for other request.  
         [0133]    In request waiting state, the client communication mechanism  11  receives communication request of program uploading, program execution start, communication with program executing state, obtaining of program execution result and so forth. In case of uploading request (step S 5  of FIG. 5), uploading request is sended to the program management mechanism  14  (step S 6  of FIG. 5) and returns the result (step S 7  of FIG. 5).  
         [0134]    In case of the execution start request (step S 8  of FIG.  5 ), the client communication mechanism  11  sends execution start request to the program execution control mechanism  16  (step S 9  of FIG. 5) to return the result (step S 10  of FIG. 5). In case of the communication request (step S 11  of FIG. 5), the client communication mechanism  11  sends the communication request to the inter-program communication mechanism  17  (step S 12  of FIG. 5) to return the result (step S 13  of FIG. 5).  
         [0135]    In case of execution result request (step S 14  of FIG. 6), the client communication mechanism  11  sends the execution result request to the program execution control mechanism  16  (step S 15  of FIG. 6) to return the result (step  16  of FIG. 6) On the other hand, in case of shut down request (step S 17  of FIG. 6), the client communication mechanism  11  returns to step S 4  to be situated in request waiting state.  
         [0136]    Here, the client communication mechanism  11  is built in a Hypertext Transfer Protocol (HTTP) server function, and communicates, with the WWW browser using the HTTP protocol.  
         [0137]    When the user management mechanism  12  receives an authentication request from the client communication mechanism  11 , an authentication information provided by the user is compared with the user information managed by itself. If the authentication information matches with the user information, the user management mechanism  12  issues permission for establishing connection. On the other hand, if the authentication information matches with the user information, the user management mechanism  12  issues rejection for connection. The authentication information and the user information are respectively consisted of user ID and password.  
         [0138]    [0138]FIG. 7 shows a structure of the user information table  23  which the user management mechanism  12  of FIG. 3 has. In FIG. 7, the user information table  23  is consisted of user ID, “user ID #1”, “user ID #2” and passwords “password #1”, “password #2”.  
         [0139]    [0139]FIG. 8 is a flowchart showing operation of the program management mechanism  14  of FIG. 3. Discussion will be given for operation of the program management mechanism  14  with reference to FIGS. 3 and 8.  
         [0140]    The program management mechanism  14  waits for request from both of the client communication mechanism  11  and the program execution control mechanism  16  (step S 21  of FIG. 8). The program management mechanism  14  is responsive to the program upload request from the client communication mechanism  11  (step  22  of FIG. 8) and calls the program verification and conversion mechanism  15  (step S 23  of FIG. 8) to verify security of the program and in conjunction therewith to convert the program into a format adapted to execution on the server computer  2 .  
         [0141]    When verification and conversion by the program verification and conversion mechanism  15  is successful (step S 24  of FIG. 8), the program management mechanism  14  registers the program in the program table  22  together with the user ID of the user who issued the uploading request, and program names before and after conversion (step S 25  of FIG. 8). In this case, if verification and conversion by the program verification and conversion mechanism  15  is not successful, the program management mechanism  14  issues error output (step S 26  of FIG. 8).  
         [0142]    On the other hand, the program management mechanism  14  is responsive to a program take out request designating the program name fed from other mechanism (S 27  of FIG. 8) to check whether the program having the designated program name as the program name before conversion is registered or not (step S 28  of FIG. 8). If the program having the designated program name as the program name is present in the registered program names, check is performed whether the stored user and the requested user are the same or not (step S 29  of FIG. 8). If the user name and the requested name are the same, the program is taken out (step S 30  of FIG. 8). If the user is not the same as the requested user, the program management mechanism  14  issues error output (step S 31  of FIG. 8).  
         [0143]    Also, when the requested program is not present in the program table  22  (not registered), the program management mechanism  14  further checks the external storage device whether the requested program name as the program name before conversion is present or not (step S 32  of FIG. 8). If the program name is present in the external storage device, the corresponding program is readout (stepS 33  of FIG. 8). If the requested program name is not found even in the external storage device, the program management mechanism  14  issues the error output (step S 31  of FIG. 8).  
         [0144]    [0144]FIG. 9 is an illustration showing a structure of the program table  22  of FIG. 3. In FIG. 9, the program table  22  is consisted of the program name before conversion, “program name #1”, “program name #2”, the registered user ID, “user ID #1”, “user ID #2”, the program name after conversion, “program name #1”, “program name #2”, and the program after conversion, “program #1”, “program #2”.  
         [0145]    [0145]FIG. 10 is a flowchart showing operation of the program execution control mechanism  16  of FIG. 3. Operation of the program execution control mechanism  16  will be discussed with reference to FIGS. 3 and 10.  
         [0146]    The program execution control mechanism  16  waits for the request (step S 41  of FIG. 10). When the program execution request is received from the client communication mechanism  11  (step S 42  of FIG. 10), the designated program is read out from the program management mechanism  14  (step S 43  of FIG. 10) to start execution thereof (step S 44  of FIG. 10). Then, the ID in executing condition is added to the management table  16   b  together with the ID of the user who actuated the program (step S 45  of FIG. 10).  
         [0147]    On the other hand, the program execution control mechanism  16  makes reference to the executing condition and is responsive to a program stop request (step S 46  of FIG. 10) to delete information of the corresponding program ID from the management table  16   b  (step S 47  of FIG. 10) and to stop executing condition of the designated program (step S 48  of FIG. 10). The designated program is deleted from the memory and the program executing condition storage mechanism  18 .  
         [0148]    The program execution control mechanism  16  deletes the program executing condition only when the program stop request is explicitly received. When execution is completed by the program per se, the program is simply interrupted temporarily and is not deleted to wait for explicit request for deletion after making reference to the result of execution by the user.  
         [0149]    [0149]FIG. 11 is an illustration showing a structure of the management able  16   b  of the program in execution stored in the program execution control mechanism  16  of FIG. 3. In FIG. 11, the management table  16   b  is consisted of the executing condition ID, “executing condition ID #1”, “executing condition ID #2”, the actuated user ID “user ID #1”, “user ID #2”, and on-execution flag, “flag #1”, “flag #2”.  
         [0150]    [0150]FIG. 12 is a block diagram showing a construction of a program executing condition  25  of FIG. 3. In FIG. 12, the program executing condition  25  is consisted of an executing condition  255  of the user program and a management information  251  of the program executing condition. The management information  251  is consisted of a temporary interrupt flag  252  indicating whether the program is temporarily interrupted or not, a message queue  253  to be used by the inter-program communication mechanism  17  and an execution result  254  upon completion of program execution.  
         [0151]    The program described by the user temporarily interrupts continuation of execution of the program by turning on the temporary interrupt flag  252  of own program executing condition. Simultaneously, the temporary interrupt instruction may designate a temporarily interrupting period. When the temporarily interrupting period is designated, after expiration of the designated period from calling of the instruction, the temporary interrupt flag is turned off by the agent server system  1  for resuming execution of the program.  
         [0152]    On the other hand, when the program executing condition as temporarily interrupted receives the message via the inter-program communication mechanism  17 , temporary interrupt is released automatically to continue execution. The program executing condition storage mechanism  18  stores the executing condition of the designated program in the external storage device.  
         [0153]    [0153]FIG. 13 is an illustration showing a data structure of the program executing condition database  24  managing the program executing condition storage mechanism  18  of FIG. 3. In FIG. 13, the program executing condition database  24  is consisted of the executing condition ID, “executing condition ID #1”, “executing condition ID #2” and a serialized executing condition, “serialized executing condition #1”, “serialized executing condition #2”.  
         [0154]    [0154]FIG. 14 is a flowchart showing operation of the program executing condition storage mechanism  18  of FIG. 3. Operation of the program executing condition storage mechanism  18  will be discussed with reference to FIGS. 3 and 14.  
         [0155]    The program executing condition storage mechanism  18  waits for the request (step S 51  of FIG. 14). When the program executing condition (storage request) is transferred from the scheduler  16   a  (step S 52  of FIG. 14), the program executing condition is serialized (step S 53  of FIG. 14) to store together with the executing condition ID (step S 54  of FIG. 14).  
         [0156]    On the other hand, when restoration of the executing condition is requested designating reference information (step S 55  of FIG. 14), the program executing condition storage mechanism  18  takes out the serialized executing condition from the program executing condition database  24  (step S 56  of FIG. 14) for restoring the serialized executing condition to the original executing condition (step S 57  of FIG. 14).  
         [0157]    [0157]FIG. 15 is a block diagram showing a construction of the inter-program communication mechanism  17  of FIG. 3. In FIG. 15, the inter-program communication mechanism  17  provides an asynchronous message delivery function. The inter-program communication mechanism  17  includes a message delivery mechanism  171  performing delivery to the message queue  253  and  263  in the program executing conditions  25  and  26 , a special program executing condition  172  for the client communication mechanism  11 , and a special program executing condition  173  for the external device communication mechanism  12 . The program may perform communication by explicitly requesting sending and reception of the message to the inter-program communication mechanism  17 .  
         [0158]    The program executing conditions  172  and  173  include management information  172   a  and  173   a  mounting message queue  172   b  and  173   b  therein. The program executing conditions 25 and  26  includes management information  251  and  261  mounting message queues  253  and  263 , and user program executing conditions  255  and  265 .  
         [0159]    [0159]FIG. 16 is a flowchart showing operation of the inter-program communication mechanism  17  of FIG. 3. Operation of the inter-program communication mechanism  17  will be discussed with reference to FIGS. 3, 15 and  16 .  
         [0160]    When the program executing condition requests sending of the message directed to other executing condition (step S 61  of FIG. 16), the inter-program communication mechanism  17  receives a message sending request. Then, the inter-program communication mechanism  17  enters the designated message to the message queue of designated other executing condition (step S 62  of FIG. 16).  
         [0161]    Subsequently, the inter-program communication mechanism  17  checks whether the designated executing condition is in temporarily interrupted state or not (step S 63  of FIG. 16). If the designated executing condition is in temporarily interrupted state, temporary interrupted state is released (step S 64  of FIG. 16).  
         [0162]    On the other hand, when the executing condition which received the message requests the message reception in the program, the message is taken out from the own message queue and is transferred to the program.  
         [0163]    The client communication mechanism  11  and the external device communication mechanism  12  also use the inter-program communication mechanism  17  similarly to the program executing condition. So that these may be handled similarly to the normal program executing condition, special program executing conditions  172  and  173  are provided in the inter-program communication mechanism  17 . While these special program executing conditions  172  and  173  are not managed by the program execution control mechanism  16 , but are stored by the program executing condition storage mechanism  18  in order to store the communicating condition.  
         [0164]    The scheduler  16   a  controls behavior with respect to executing condition of the program registered in the management table  16   b  and has a function to make the actual program to be executed. The scheduler  16   a  operates by repeating group of processes called as “turn”.  
         [0165]    [0165]FIG. 17 is a flowchart showing operation of the scheduler  16   a  of FIG. 3. Operation of the scheduler  16   a  will be discussed with reference to FIGS. 3 and 14.  
         [0166]    At first in the turn, the scheduler  16   a  selects executing condition of the program to be executed within the turn among the executing condition ID of the programs registered in the management table  16   b  and lists those (step S 71  of FIG. 17).  
         [0167]    Next, the scheduler  16   a  sets a list the same as the list of executing condition to be executed as an initial value of the list of the executing condition to be stored in the final turn (step S 72  of FIG. 17).  
         [0168]    Subsequently, the scheduler  16   a  makes judgment whether the program executing condition is on execution or on temporarily interrupted state for all executing conditions contained in the list of the executing conditions to be executed (steps S 73  and S 74  of FIG. 17). If the executing condition is on execution, only one execution unit of the program may be executed (step S 75  of FIG. 17).  
         [0169]    When execution of one execution unit is completed, the scheduler  16   a  checks presence or absence of message sending on execution (step S 76  of FIG. 17). When message sending is present, a sending destination executing condition ID is added to the list of the executing condition to be stored (step S 77  of FIG. 17). The scheduler  16   a  repeats the process to the end of the list (steps S 74  to S 79  of FIG. 17).  
         [0170]    Finally, the scheduler  16   a  transfers all executing conditions contained in the list of the executing conditions to be stored to the program executing condition storage mechanism to store simultaneously (step S 80  of FIG. 17). As a result, all of executing conditions which are executed, and all of executing conditions receiving the messages are stored.  
         [0171]    When inter-program communication is performed during execution by storing the executing conditions in a lump after execution, the program executing conditions of message sender and sending destination are always stored in either condition that the sender does not yet send the message and the sending destination does not yet receive the message or that the sender sended the message and the sending destination received the message. Even when the agent server unit  1  causes failure to interrupt operation during delivery of the message or storing of the executing condition and resumption of execution thereafter, execution can be continued without causing discrepancy, such as loss or doubling of message delivery or the like.  
         [0172]    Furthermore, by simultaneously performing execution and storing of a plurality of program executing conditions in a lump, storing of the executing condition can be performed efficiently when communication is concentrated to particular executing condition, in comparison with the case where only one executing condition is executed and stored at one time.  
         [0173]    When ten program executing conditions send messages to one program executing condition, by executing and storing ten executing conditions in a lump to permit storing of the executing condition on the message reception side at one time to require storing of eleven executing conditions in total. In contrast to this, when execution and storing of only one executing condition at one time to require storing of two executing conditions at the message sender and message sending destination to require storing cumulatively twenty executing conditions.  
         [0174]    [0174]FIG. 18 is a flowchart showing operation of the agent server unit  1  of FIG. 1 upon actuation. Operation of the agent server unit  1  upon actuation will be discussed with reference to FIGS. 3 and 18.  
         [0175]    Upon actuation (step S 81  of FIG. 19), the agent server unit  1  performs initialization of all mechanism except for the scheduler  16   a  (step S 82  of FIG. 18) for preparation of enabling operation of the agent server unit  1 .  
         [0176]    Next, the agent server unit  1  checks the program executing condition storage mechanism  18  whether the program executing condition is already stored or not (step S 83  of FIG. 18). If already stored, all of stored program executing conditions are restored (step S 84  of FIG. 18). Thereafter, the scheduler  16   a  is initialized to initiate execution of the scheduler  16   a  (step S 85  of FIG. 18). By this, operation of the agent server unit  1  is initiated (step S 86  of FIG. 18).  
         [0177]    [0177]FIG. 19 is a flowchart showing operation of the program verification and conversion mechanism  15  of FIG. 3. Operation of the program verification and conversion mechanism  15  will be discussed with reference to FIGS. 3 and 19.  
         [0178]    The program verification and conversion mechanism  15  inhibits execution of instruction which is not desirable to execute by the uploaded program, or performs conversion of the program with maintaining meaning of the program so that excessive amount of calculation resource or memory is not used against intension of the server computer  2 .  
         [0179]    As an example of instruction sequence inhibited execution, Application Program Interface (API) of the interpreter which stops execution of the server process per se including the uploaded program, may be considered.  
         [0180]    When such instruction sequence is executed by the uploaded program, not only the program but also the server process per se stop execution. The present invention ensures security by finding such instruction sequence before execution of the program or re-writing such instruction sequence into secure instruction sequence.  
         [0181]    For example, upon mounting using Java language as the preferred embodiment of the present invention, it is possible to find the following instruction sequences.  
                                                       n   iconst_0           n+1   invokestatic  #2                      
 
         [0182]    The foregoing instruction sequence is a result of translation of “System. exit (0)” in Java language into Java byte code. This expression means stop of execution of Java program executing this expression to stop execution of the server process per se. For preventing this, it is desirable to reject execution of the program including the instruction sequence as set forth above.  
         [0183]    On the other hand, for example, upon inspecting a memory amount to be used, in mounting using Java language as the preferred embodiment of the present invention, obtaining of the memory is performed by only following instructions.  
         [0184]    new  
         [0185]    newarray  
         [0186]    anewarray  
         [0187]    By re-writing these instructions with adding instruction sequence for discriminating use amount of the memory, use amount of the memory can be restricted.  
         [0188]    For example, in case of the instruction sequence of  
         [0189]    new class foo,  
         [0190]    the instruction sequence is re-written with a following pseudo code:  
         [0191]    if (size of class foo+heretofore memory use amount  
                                                         &lt; memory use amount restriction)            {       Program execution end       }                  
 
         [0192]    new class foo.  
         [0193]    As set forth above, avoiding of the instruction sequence which is dangerous to execute and restriction of the memory use amount can be easily realized using the program verification and conversion function.  
         [0194]    At first, the program verification and conversion mechanism  15  reads the program code (step S 91  of FIG. 19), a counter PC (program code) is set at program execution start position (step S 92  of FIG. 19), and then scanning of the entire program is continued (step S 93  of FIG. 19). The program verification and conversion mechanism  15  scans the entire program (step  93  of FIG. 19) to enable execution of the program (step S 101  of FIG. 19). Then, process goes end.  
         [0195]    The program verification and conversion mechanism  15  reads out the instruction sequence started from the position of PC (step S 94  of FIG. 19). Then, check is effected whether the instruction sequence in question is the instruction sequence preliminarily determined for inhibited to use (step S 95  of FIG. 19). If use inhibited, the program is inhibited execution to stop subsequent process (step  100  of FIG. 19).  
         [0196]    On the other hand, the program verification and conversion mechanism  15  performs discrimination whether the instruction sequence in question is usable instruction sequence or not (step S 96  of FIG. 19). Otherwise, the program is inhibited execution to stop subsequent process (step  100  of FIG. 19).  
         [0197]    Subsequently, the program verification and conversion mechanism  15  discriminates whether the instruction sequence is to be object to be preliminarily re-written or not (step S 97  of FIG. 19). If so, the instruction sequence is actually re-written (step S 98  of FIG. 19). Finally, the counter PC is advanced for a length of the instruction sequence (step S 99  of FIG. 19). The foregoing process repeats execution until scanning of the entire program.  
         [0198]    [0198]FIG. 20 is a flowchart showing operation of the program verification and conversion mechanism  15  of FIG. 3. A method for restricting calculation amount of one program will be discussed with reference to FIGS. 3 and 20.  
         [0199]    For restricting calculation amount of the program, in addition to the foregoing process, the following program conversion which will be discussed later, will be performed. The program using CPU resource without restriction has a loop structure in the program and repeats the loop for many times. In the present invention, an instruction sequence to inspect execution period is inserted at the beginning of the loop so that when a given period is exceeded, execution of the program is stopped so as not to continue execution of respective program infinitely.  
         [0200]    At first, the program verification and conversion mechanism  15  reads in the program code (step S 111  of FIG. 20), and generates a control flow graph for the program (step S 112  of FIG. 20). This can be realized by known technology. For example, A. V. Apho, R. Sesy, and J. D. Ulman, “Compiler II”, page 643, discloses such technology. Disclosure of the foregoing publication is herein incorporated by reference.  
         [0201]    The program verification and conversion mechanism  15  specifies start position of the loop on the basis of the control flow graph (step S 113  of FIG. 20). This can also be easily realized by the known technology. For example, A. V. Apho, R. Sesy, and J. D. Ulman, “Compiler II”, page 648, discloses such technology.  
         [0202]    The program verification and conversion mechanism  15  inserts the instruction sequence for initializing parameter representative of execution period, to the beginning end of the program (step S 114  of FIG. 20). Finally, at the leading end of the loop identified by step S 113 , an instruction sequence for stopping execution of the program is inserted when a current timing is obtained and execution period exceeds a given value (step  115  of FIG. 20).  
         [0203]    [0203]FIG. 21 is a flowchart showing operation of the program management mechanism  14  in the second embodiment of the present invention. The second embodiment of the present invention will be discussed with reference to FIG. 21. The second embodiment of the program execution service providing system according to the present invention has the same construction as the construction of the first embodiment of the program execution service providing system of FIG. 3 and only differentiated in operation. Therefore, discussion will be given hereinafter for operation.  
         [0204]    In the first embodiment of the present invention, all of the programs uploaded by the user are verified and converted. However, it may be possible to eliminate calling of the program verification and conversion mechanism  15  when the program management mechanism  14  makes judgment that the program is secure not requiring verification by preliminary set in the program management mechanism  14 , author of the program, program uploading user.  
         [0205]    The program management mechanism  14  waits for request from both of the client communication mechanism  11  and the program execution control mechanism  16  (step S 121  of FIG. 21). When the program uploading request is received from the client communication mechanism  11  (step S 122  of FIG. 21), the program management mechanism  14  checks whether verification and conversion of the program can be eliminated or not (step S 123  of FIG. 21). If verification and conversion of the program can be eliminated, the program is registered instantly (step S 126  of FIG. 21).  
         [0206]    Otherwise, the program management mechanism  14  calls the program verification and conversion mechanism  15  (step S 124  of FIG. 21) to verify security of the program and converts the program into a format adapted for execution on the server computer  2 .  
         [0207]    When verification and conversion by the program verification and conversion mechanism  15  is successful (step S 125  of FIG. 21), the program management mechanism  14  registers the program in the program table  22  together with the user ID of the user who issued the uploading request, and program names before and after conversion (step S 126  of FIG. 21). In this case, if verification and conversion by the program verification and conversion mechanism  15  is not successful, the program management mechanism  14  issues error output (step S 127  of FIG. 21).  
         [0208]    On the other hand, the program management mechanism  14  is responsive to a program take out request designating the program name fed from other mechanism (S 128  of FIG. 21) to check whether the program having the designated program name as the program name before conversion is registered or not (step S 129  of FIG. 21). If the program having the designated program name as the program name is present in the registered program names, check is performed whether the stored user and the requested user are the same or not (step S 130  of FIG. 21). If the user name and the requested name are the same, the program is taken out (step S 131  of FIG. 21). If the user is not the same as the requested user, the program management mechanism  14  issues error output (step S 132  of FIG. 21).  
         [0209]    Also, when the requested program is not present in the program table  22  (not registered), the program management mechanism  14  further checks the external storage device whether the requested program name is present or not (step S 133  of FIG. 21). If the program name is present in the external storage device, the corresponding program is read out (step S 134  of FIG. 21). If the requested program name is not found even in the external storage device, the program management mechanism  14  issues the error output (step S 132  of FIG. 21).  
         [0210]    As set forth above, by checking whether verification and conversion of the program can be eliminated or not, it becomes possible to eliminate process cost required for verification and conversion and to execute the program operating resource which is not permitted for general programs.  
         [0211]    Next, the third embodiment of the present invention will be discussed. The third embodiment of the program execution service providing system according to the present invention is constructed similar to the first embodiment of the program execution service providing system according to the invention shown in FIG. 3, and is only differentiated in operation. Discussion will be given for operation.  
         [0212]    In the first embodiment of the present invention, the program is regularly executed for one execution unit by the scheduler  16   a . Executing condition of each individual program has unique thread and may be executed in parallel to the scheduler  16   a  or the executing condition of other program.  
         [0213]    Therefore, in the third embodiment of the present invention, the scheduler  16   a  does not perform execution of one execution unit but monitors occupying period of CPU of each thread to lower preferential level or to temporarily interrupt the thread and so forth if occupying period is excessively long, to lower occupation of CPU resource.  
         [0214]    On the other hand, in the third embodiment of the present invention, regularly or when communication is performed by program, the thread is temporarily interrupted to store the executing condition of the program at that timing.  
         [0215]    [0215]FIG. 22 is a block diagram showing a construction of the fourth embodiment of the program execution service providing system according to the present invention. In FIG. 22, the fourth embodiment of the program execution service providing system according to the present invention has the same construction as the first embodiment of the program execution service providing system according to the present invention shown in FIG. 3, except that a management program executing condition  41  is added. In the following discussion, like elements to those in the first embodiment of the present invention will be identified by like reference numerals, and operation of like elements are the same as those in the first embodiment of the present invention.  
         [0216]    In the first embodiment of the present invention, the user directly operates the program execution control mechanism  16  in the server computer  2  via the client communication mechanism  11 . By this, control operation of initiation, stop and so forth of execution of the program is performed. In the fourth embodiment of the present invention, the server management program is uploaded as the program. Then, the user performs the control operation of the program by communicating with the server management program. The management program executing condition  41  shows executing condition of the server management program.  
         [0217]    In this case, by adding various function to the server management program, it becomes possible to realize continuously actuation or control of a plurality of programs by batch process or initiation of execution of the next program on the basis of result of execution of a plurality of programs without varying function of the control portion of the server computer  2 . Furthermore, by uploading the server management program, the management function can be updated.  
         [0218]    [0218]FIG. 23 is a block diagram showing a construction of the fifth embodiment of the program execution service providing system according to the present invention. In FIG. 23, the fifth embodiment of the program execution service providing system according to the present invention has similar construction as the first embodiment of the program execution service providing system according to the present invention of FIG. 3 except for adding an accounting database (DB) 51 . In the following discussion, like elements to those in the first embodiment of the present invention will be identified by like reference numerals, and operation of like elements are the same as those in the first embodiment of the present invention.  
         [0219]    In the first embodiment of the present invention, no consideration has been paid with respect to use amount of various resource of the server by the user, whereas in the fifth embodiment of the present invention, an accounting database  51  is provided in the server computer  2  for recording number of class upload, number of program actuation, CPU occupying period of the actuated programs, memory use amount of the actuated programs and so forth, per user.  
         [0220]    In the accounting database  51 , information for storing accounting information used by the server computer  2  is accumulated. The program management mechanism  14  or the program execution control mechanism  16  records the imformation in the accounting database  51  as required.  
         [0221]    [0221]FIG. 24 is an illustration showing a data structure of the accounting database  51  of FIG. 23. In FIG. 24, in the accounting database  51 , user ID, “user ID #1”, “user ID #2” of the user used the service, kind of used function “upload”, “program actuation”, and amount of function “upload number #1”, “actuation number #2” are additionally recorded sequentially as a set.  
         [0222]    [0222]FIG. 25 is a flowchart showing operation of the program management mechanism  14  of FIG. 23. Operation of the program management mechanism  14  will be discussed with reference to FIGS.  23  to  25 .  
         [0223]    The program management mechanism  14  waits for request from both of the client communication mechanism  11  and the program execution control mechanism  16  (step S 141  of FIG. 25). The program management mechanism  14  is responsive to the program upload request from the client communication mechanism  11  (step  142  of FIG. 25) and calls the program verification and conversion mechanism  15  (step S 143  of FIG. 25) to verify security of the program and in conjunction therewith to convert the program into a format adapted to execution on the server computer  2 .  
         [0224]    When verification and conversion by the program verification and conversion mechanism  15  is successful (step S 144  of FIG. 25), the program management mechanism  14  registers the program in the program table  22  together with the user ID of the user who issued the uploading request, and program names before and after conversion (step S 145  of FIG. 25), and accounting information is added to the accounting database  51  (step S 146  of FIG. 25). In this case, if verification and conversion by the program verification and conversion mechanism  15  is not successful, the program management mechanism  14  issues error output (step S 147  of FIG. 25).  
         [0225]    On the other hand, the program management mechanism  14  is responsive to a program take out request designating the program name fed from other mechanism (S 148  of FIG. 25) to check whether the program having the designated program name as the program name before conversion is registered or not (step S 149  of FIG. 25). If the program having the designated program name as the program name is present in the registered program names, check is performed whether the stored user and the requested user are the same or not (step S 150  of FIG. 25). If the user name and the requested name are the same, the program is taken out (step S 151  of FIG. 25). If the user is not the same as the requested user, the program management mechanism  14  issues error output (step S 152  of FIG. 25).  
         [0226]    Also, when the requested program is not present in the program table  22  (not registered), the program management mechanism  14  further checks the external storage device whether the requested program name is present or not in it (step S 153  of FIG. 25). If the program name is present in the external storage device, the corresponding program is read out (step S 154  of FIG. 25). If the requested program name is not found even in the external storage device, the program management mechanism  14  issues the error output (step S 152  of FIG. 25).  
         [0227]    [0227]FIG. 26 is a flowchart showing operation of the program execution control mechanism  16  of FIG. 23. Operation of the program execution control mechanism  16  will be discussed with reference to FIGS. 23, 24 and  26 .  
         [0228]    The program execution control mechanism  16  waits for the request (step S 161  of FIG. 26). When the program execution request is received from the client communication mechanism  11  (step S 162  of FIG. 26), the designated program is read out from the program management mechanism  14  (step S 163  of FIG. 26).  
         [0229]    The program execution control mechanism  16  initiates the execution (step  164  of FIG. 26) to add the ID of the executing condition together with the ID of the user actuated the program to the management table  16   b  (step S 165  of FIG. 26) and to add the accounting information for the accounting database  51  (step S 166  of FIG. 26).  
         [0230]    On the other hand, the program execution control mechanism  16  makes reference to the executing condition and is responsive to a program stop request (step S 167  of FIG. 26) to delete information of the corresponding program ID from the management table  16   b  (step S 168  of FIG. 26) and to stop executing condition of the designated program (step S 169  of FIG. 26). The designated program is deleted from the memory and the program executing condition storage mechanism  18 .  
         [0231]    The program execution control mechanism  16  deletes the program executing condition corresponding to the program stop request only when the program stop request is explicitly received. When execution is completed by the program per se, the program is simply interrupted temporarily and is not deleted to wait for explicit request for deletion after making reference to the result of execution by the user.  
         [0232]    [0232]FIG. 27 is a flowchart showing operation of the scheduler  16   a  of FIG. 23. Operation of the scheduler  16   a  will be discussed with reference to FIGS. 23, 24 and  27 .  
         [0233]    At first in the turn, the scheduler  16   a  selects executing condition of the program to be executed within the turn among the executing condition ID of the programs registered in the management table  16   b  and lists those (step S 171  of FIG. 27).  
         [0234]    Next, the scheduler  16   a  sets a list the same as the list of executing condition to be executed as an initial value of the list of the executing condition to be stored in the final turn (step S 172  of FIG. 27).  
         [0235]    Subsequently, the scheduler  16   a  makes judgment whether the program executing condition is on execution or on temporarily interrupted state for all executing conditions contained in the list of the executing conditions to be executed (steps S 173  and S 174  of FIG. 27). If the executing condition is on execution, only one execution unit of the program may be executed (step S 175  of FIG. 27). After completion of execution of one execution unit of each executing condition, respective CPU and memory use amount are stored.  
         [0236]    When execution of one execution unit is completed, the scheduler  16   a  checks presence or absence of message sending on execution (step S 176  of FIG. 27). When message sending is present, a sending destination executing condition ID is added to the list of the executing condition to be stored (step S 177  of FIG. 27). The scheduler  16   a  repeats the process to the end of the list (steps S 174  to S 179  of FIG. 27).  
         [0237]    Finally, the scheduler  16   a  transfers all executing conditions contained in the list of the executing conditions to be stored to the program executing condition storage mechanism to store simultaneously (step S 180  of FIG. 27). After end of storing of the executing condition, the stored CPU and memory use amounts are added to the accounting database  51  (step S 181  of FIG. 27). As a result, all of executing conditions which are executed, and all of executing conditions receiving the messages as a result of execution of the executing conditions, are stored.  
         [0238]    A manager or administrator of the server computer  2  may check use amount of the server resource by each individual user for accounting to the user by making reference to the record on the accounting database  51 , and may apply restriction of use for the user using excessive amount of server resource.  
         [0239]    Next, the sixth embodiment of the present invention will be discussed. The sixth embodiment of the program execution service providing system according to the present invention is constructed similar to the first embodiment of the program execution service providing system according to the invention shown in FIG. 3, and is only differentiated in operation. Discussion will be given for operation.  
         [0240]    In the first embodiment of the present invention, there is a constraint that the uploaded program can be taken out from the program management mechanism  14  only by the user who uploaded the program. However, in the sixth embodiment of the present invention, for program registration, a condition of the user who can use the program is stored in place of the registering user information to permit the user to take out the program when the user requesting taking out satisfies the condition, upon occurrence of the program taking out request.  
         [0241]    In this case, the first embodiment of the present invention handles as special case where this condition is “requested user is equal to the uploaded user”. As an example of this condition, the requesting user belonging a particular user group, the requesting user having particular executing authority, the requesting user holding particular contract with the uploading user, and so forth are considered. By storing the conditions, it becomes possible to make the uploaded program common between a plurality of users on the basis of variety of policies.  
         [0242]    Next, discussion will be given for the seventh embodiment of the present invention. The seventh embodiment of the program execution service providing system according to the present invention is constructed similar to the first embodiment of the program execution service providing system according to the invention shown in FIG. 3, and is only differentiated in operation. Discussion will be given for operation.  
         [0243]    In the first embodiment of the present invention, the program to be uploaded is the program per se to be actuated, whereas, in the seventh embodiment of the present invention, the program is constructed with a plurality of components and permits uploading of a part of the components.  
         [0244]    When the program is to be taken out, when taking out request is issued to the program management mechanism  14  with designating one component similarly to taking out normal one program, the program management mechanism  14  checks necessary other components to return those components combined into one program to the requesting user. As means for checking the necessary other components, dynamic class load function or the like supported by Java language as preferred embodiment of the present invention and so forth may be used.  
         [0245]    By this, among the programs, by preliminarily uploading only portion having high reusability to be used frequently, and subsequently uploading only portion having low reusability to be called, a program size for uploading can be made smaller.  
         [0246]    On the other hand, by permitting only portion of the library to be taken out by the user other than the user who uploaded the library as in the sixth embodiment of the present invention, a program realizing the user&#39;s request can be easily generated using the components prepared by other users.  
         [0247]    [0247]FIG. 28 is a flowchart showing operation of the eighth embodiment of the scheduler according to the present invention. Operation of the eighth embodiment of the scheduler according to the present invention will be discussed with reference to FIG. 28. The eighth embodiment of the program execution service providing system according to the present invention is constructed similar to the first embodiment of the program execution service providing system according to the invention shown in FIG. 3, and is only differentiated in operation. Discussion will be given for operation.  
         [0248]    In the first embodiment of the present invention, the executing condition of the actuated program is stored in the database and all of the uploaded programs are all managed on the memory. In contrast to this, in the eighth embodiment of the present invention, the program executing condition which is in temporarily interrupted and is not executed instantly, is stored in the program executing condition storage mechanism  18  and is deleted from the memory. Subsequently, upon executing the program, the program executing condition is read out from the program executing condition storage mechanism  18  to the memory.  
         [0249]    At first in the turn, the scheduler  16   a  selects executing condition of the program to be executed within the turn among the executing condition ID of the programs registered in the management table  16   b  and lists those (step S 191  of FIG. 28). Then, necessary executing condition (executing condition contained in the list) is read on the memory using the program executing condition storage mechanism  18  (step S 192  of FIG. 28).  
         [0250]    Next, the scheduler  16   a  sets a list the same as the list of executing condition to be executed as an initial value of the list of the executing condition to be stored in the final turn (step S 193  of FIG. 28).  
         [0251]    Subsequently, the scheduler  16   a  makes judgment whether the program executing condition is on execution or on temporarily interrupted state for all executing conditions contained in the list of the executing conditions to be executed (steps S 194  and S 195  of FIG. 28). If the executing condition is on execution, only one execution unit of the program may be executed (step S 196  of FIG. 28).  
         [0252]    When execution of one execution unit is completed, the scheduler  16   a  checks presence or absence of message sending on execution (step S 197  of FIG. 28). When message sending is present, a sending destination executing condition ID is added to the list of the executing condition to be stored (step S 198  of FIG. 28). The scheduler  16   a  repeats the process to the end of the list (steps S 195  to S 200  of FIG. 28).  
         [0253]    Finally, the scheduler  16   a  transfers all executing conditions contained in the list of the executing conditions to be stored to the program executing condition storage mechanism to store simultaneously (step S 201  of FIG. 28). Then, the stored executing conditions are deleted from the momory. As a result, all of executing conditions which are executed, and all of executing conditions receiving the messages as a result of execution of the executing conditions, are stored.  
         [0254]    [0254]FIG. 29 is a flowchart showing operation of the inter-program communication mechanism in the eighth embodiment of the present invention. Operation of the inter-program communication mechanism of the eighth embodiment of the present invention will be discussed with reference to FIG. 29.  
         [0255]    When the program executing condition requests sending of the message directed to other executing condition (step S 211  of FIG. 29), the inter-program communication mechanism  17  checks whether the objective executing condition is present on the memory or not (step  212  of FIG. 29). If the objective executing condition is not present on the memory, the program executing condition of the sending destination is read (step S 213  of FIG. 29).  
         [0256]    The inter-program communication mechanism  17  enters the designated message to the message queue of designated other executing condition (step S 214  of FIG. 29). Subsequently, the inter-program communication mechanism  17  checks whether the designated executing condition is in temporarily interrupted state or not (step S 215  of FIG. 29). If the designated executing condition is in temporarily interrupted state, temporary interrupted state is released (step S 216  of FIG. 29). By this. large amount of programs can be simultaneously actuated on relatively small capacity of memory.  
         [0257]    [0257]FIG. 30 is a block diagram showing a use mode of the ninth embodiment of the agent server unit according to the present invention. In FIG. 30, both of the server computer  2  and the client computer  3  are connected to the network  100  for communication through the network  100 . The agent server unit  1  operates on the server computer  2 . The storage medium  5  of the agent server unit  1  is connected to the server computer  2 .  
         [0258]    On the storage medium  5 , the program showing operation of the agent server unit of any of the first to eighth embodiment of the present invention set forth above may be stored. The server computer  2  reads the program of the agent server unit  1  from the storage medium  5  for execution. It should be noted that as the storage medium  5 , ROM (read-only memory), an IC (integrated circuit) memory and so forth may be used.  
         [0259]    The program uploaded on the server computer  2  is executed with conversion into a format adapted for operation on the server computer  2  after verification in view of security. Therefore, the manager or administrator of the server is not required to unnecessarily restrict or limit operation to the programs as uploaded, to increase freedom in the program of the user. Therefore, wide variety of processes desired by the user are transferred to the server computer via the general purpose user interface of the client computer  3  to execute on the server computer  2 .  
         [0260]    Since the executing condition of the program is automatically stored by the server computer  2 , it becomes possible to execute not only continuous process not requiring storing of the executing condition, such as monitoring process, but also continuous process requiring storing of the executing condition, such as automatic transaction of stock.  
         [0261]    Furthermore, by the external device communication mechanism  13  or the inter-program communication mechanism  17 , cooperation with other program or process using other system other than the agent server unit  1  may also be executed.  
         [0262]    In general, an execution parsing mechanism of the program, such as interpreter or the like requires a plurality of instruction of the program of the platform for executing one instruction of the program as execution object. Therefore, execution performance is thus lower in comparison with the case where the program is directly executed on the platform.  
         [0263]    In the present invention, instead of parsing and executing the uploaded program by the agent server unit  1  per se, the uploaded program is taken as a part of the program of the agent server unit  1  per se by verification and conversion of the program, with maintaining security of execution and fairness of calculation resource and so forth and can be directly executed on the platform  21  to efficiently execute the uploaded program.  
         [0264]    On the other hand, in addition that the program executing condition is automatically stored in the database or file system at an appropriate timing by the agent server unit  1 , the program executing condition of the sending destination of the message sended before storing of the program executing condition is also stored simultaneously so as not to cause discrepancy of message delivery. Therefore, when the agent server unit  1  is stopped by failure during operation, execution of the program can be continued without causing discrepancy upon resumption of operation of the agent server unit  1 .  
         [0265]    Furthermore, by executing a plurality of executing conditions in a lump, and when results of execution are to be stored, storing is also performed in a lump adapted to executing condition. Thus, even when one executing condition receives messages from a plurality of executing conditions, those messages can be stored in one storing operation to efficiently store the executing conditions.  
         [0266]    As set forth above, with the program execution service providing system according to the present invention, the program uploaded on the server is verified the security, converted into the format adapted to execution on the server to realize the system, in which the user of the service may receive service specialized for own request.  
         [0267]    With another program execution service providing system according to the present invention, by automatically storing the executing condition of the program by the server, even when the process is continuous process requires storing of the executing condition and includes interaction with the process outside of the system and other process, the executing condition can be certainly stored without discrepancy.  
         [0268]    With other program execution service providing system of the present invention, instead of parsing and executing the uploaded program by server per se, the uploaded program is taken as a part of the program of the agent server unit  1  per se by verification and conversion of the program, with maintaining security of execution and fairness of calculation resource and so forth and can be directly executed on the platform  21  to efficiently execute the uploaded program.  
         [0269]    Although the present invention has been illustrated and described with respect to exemplary embodiment thereof, it should be understood by those skilled in the art that the foregoing and various other changes, omission and additions may be made therein and thereto, without departing from the spirit and scope of the present invention. Therefore, the present invention should not be understood as limited to the specific embodiment set out above but to include all possible embodiments which can be embodied within a scope encompassed and equivalent thereof with respect to the feature set out in the appended claims.