Data processing: database and file management or data structures – Database design – Data structure types
Reexamination Certificate
1998-09-18
2001-07-31
Alam, Hosain T. (Department: 2142)
Data processing: database and file management or data structures
Database design
Data structure types
C707S793000, C707S793000, C707S793000, C717S152000, C711S133000
Reexamination Certificate
active
06269371
ABSTRACT:
BACKGROUND OF THE INVENTION
The present invention relates to a computer system which operates upon downloading programs and data from a server (server computer) via a network, and a file resources switching method applied to the computer system.
This application is based on Japanese Patent Application No. 10-047287 filed on Feb. 27, 1998, the content of which is incorporated herein by reference.
In recent years, new computer architectures called Network Computers have been developed instead of personal computers.
The network computer is designed to be used based on connection to a network. All programs and data necessary for data processing are downloaded from a server via a network. Therefore, each network computer operating as a client computer need not have programs and data, and can flexibly cope with, e.g., updating of an Operating System (OS) and application programs. As a result, total costs of ownership can be drastically reduced.
However, as described above, the network computer is designed to be used based on connection to a network, and is not usually designed to be used in a mobile environment where the computer is disconnected to the network. It is, therefore, necessary to develop a new network computer which can perform the same operations as in the online state in which the computer is connected to the network even if the computer operates in the offline state in which the computer is not connected to the network.
In order to realize a network computer which can be used in a mobile environment, it is necessary to provide a local storage, in which copies of resources on the server necessary for operating in the offline state are stored, in the network computer and to enable the network computer to operate using the local storage device.
In this case, however, the file system to be accessed differs between the online state and the offline state. As a result, it is necessary to clearly distinguish the network file system of the server from the local file system of the local storage. For this reason the user or the application program of the network computer must explicitly designate a file system to be accessed while being aware of the state of the connection of the network computer to a network. Furthermore, the network file system of the server cannot be accessed in the same procedures as those of the local file system of the local storage.
Note that “file system” means “hierarchy structured file set” and “file system” will be used based on this meaning hereinafter.
BRIEF SUMMARY OF THE INVENTION
It is the first object of the present invention to provide a computer system capable of efficiently using a network computer for mobile uses.
It is the second object of the present invention to provide a file resources switching method applied to the computer system.
It is the third object of the present invention to provide a computer program product used in the computer system.
The first object is achieved by the following computer system. That is, the computer system of the present invention comprises a server computer; and a network computer operating upon downloading programs and data necessary for data processing from the server computer, wherein the network computer comprising: a local storage device in which at least a part of resources including the programs and data stored in a file system of the server computer are stored as a replica; determination means for determining a connection state of the network computer to the server computer; and file system allocation means for selectively allocating the file system of the server computer and a local file system stored as a replica in the local storage device to the network computer in accordance with the determination result made by the determination means.
The second object is achieved by the following file resources switching method. That is, the file resource switching method of the present invention, applied to a network computer, the network computer having a local storage device in which at least a part of resources including programs and data stored in a file system of a server computer are stored as a replica by downloading the resources from the server computer, the method comprising: a determination step of determining a connection state of the network computer to the server computer, and a step of selectively allocating the file system of the server computer and a local file system stored as a replica in the local storage device to the network computer in accordance with the determination result made by the determination step.
In this computer system, in accordance with whether the network computer is in an online mode connection state in which the network computer is connected to the server or in a mobile mode connection state in which the network computer is not connected to the server, a file system allocated to the network computer is automatically switched. Therefore, the user or application program does not have to be aware of a file system to be accessed. In addition, the user or application program can use a common file access pass to both the file system of the server and the local file system of the local storage device. As a result, it is possible to perform processing using the file resources on the server when the network computer is in an online mode connection state, and processing using replicas of the file resources in the local storage device when the network computer is in a mobile mode connection state. A computer system suitable for realizing a network computer for mobile uses is thus provided.
The computer system of the present invention comprises a server computer; and a network computer operating upon downloading programs and data necessary for data processing from the server computer, wherein the network computer comprising: a local storage device in which at least a part of resources including the programs and data stored in a file system of the server computer are stored as a replica; directory mount control means for mounting the file system of the server computer as a home directory of file resources and mounting a local file system stored as a replica in the local storage device as a replica directory, when the network computer is in a PPP connection state in which the network computer is connected to the server computer by PPP, determination means for determining whether a software to be accessed is stored in the local file system stored in the local storage device as a replica, and file access means for accessing the local file system of the local storage device or the file system of the server computer in accordance with a determination result made by the determination means.
The network computer for mobile uses may be connected to the server via a network outside the office. In this case, communication speed is slowed down. Due to this, if a software to be accessed is stored in the local file system of the local storage device, it is preferable to access the local file system. Thus, by automatically switching the file system to be accessed in accordance with whether a software, designated by a file access pass included in a file access request from the user or the application program, is stored, it is possible to select the most suitable file system while the user or the application program of the computer system is not at all aware of a file system to be accessed.
Additional objects and advantages of the invention will be set forth in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. The objects and advantages of the invention may be realized and obtained by means of the instrumentalities and combinations particularly pointed out hereinafter.
REFERENCES:
patent: 5721916 (1998-02-01), Pardikar
patent: 5781909 (1998-07-01), Logan et al.
patent: 5828876 (1998-10-01), Fish et al.
patent: 5893116 (1999-04-01), Simmonds et al.
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patent: 5905492 (1999-05-01), Straub et al.
patent: 5937421 (1999-08-01), Petrov et al.
patent: 5991771 (1999-11-01), Falls e
Alam Hosain T.
Finnegan Henderson Farabow Garrett & Dunner L.L.P.
Kabushiki Kaisha Toshiba
Ly Anh
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