Abstract: A first information processing device holds data and a key for encryption. A second information processing device does not have rights to share data not encrypted with the first information processing device and a client. The first information processing device transmits data and key to the client when receiving a request to use the data. The first information processing device generates first encrypted data encrypted with the key, and transmits it to the second information processing device. The client transmits information obtained by encrypting the result of processing on the data with the key to the second information processing device until the use of the data ends. The first information processing device acquires second encrypted data received by the second information processing device from the second information processing device, and decrypts and stores it when notified that the use of the data has ended.

Abstract: A system includes a plurality of storage devices and an information processing device including a cache memory. The information processing device is configured to access the plurality of storage devices. When a failure has occurred in a first storage device included in the plurality of storage devices, the information processing device perform a procedure including: specifying a second storage device in which no failure has occurred, among the plurality of storage devices, creating an invisible file including a cache that has been stored in the cache memory and is to be stored in the first storage device, and storing the created invisible file in the second storage device. The information processing device stores the cache included in the invisible file stored in the second storage device, in the first storage device when the failure of the first storage device is eliminated.

Abstract: A first information processing device holds data and a key for encryption. A second information processing device does not have rights to share data not encrypted with the first information processing device and a client. The first information processing device transmits data and key to the client when receiving a request to use the data. The first information processing device generates first encrypted data encrypted with the key, and transmits it to the second information processing device. The client transmits information obtained by encrypting the result of processing on the data with the key to the second information processing device until the use of the data ends. The first information processing device acquires second encrypted data received by the second information processing device from the second information processing device, and decrypts and stores it when notified that the use of the data has ended.

Abstract: A system includes a plurality of storage devices and an information processing device including a cache memory. The information processing device is configured to access the plurality of storage devices. When a failure has occurred in a first storage device included in the plurality of storage devices, the information processing device perform a procedure including: specifying a second storage device in which no failure has occurred, among the plurality of storage devices, creating an invisible file including a cache that has been stored in the cash memory and is to be stored in the first storage device, and storing the created invisible file in the second storage device. The information processing device stores the cache included in the invisible file stored in the second storage device, in the first storage device when the failure of the first storage device is eliminated.

Abstract: A distributed processing system which enables a plurality of computers to make quick access to a shared storage unit. A storage quota management unit manages storage quotas, which limit the total amount of data that each user can store on the shared storage unit. When a write request to the shared storage unit is issued at a certain computer, a user identification unit identifies the requesting user. Then a free quota calculation unit calculates the remaining free storage quota of the identified user. A reserve space allocation unit allocates an appropriate reserve space to the computer according to the remaining free storage quota, allowing the computer to use the allocated reserve space at its discretion to handle the user's data write request.

Abstract: The communications statuses of a plurality of clients are checked in a fixed cycle; when a check result corresponding to at least one of the clients is irregular, the estimated number of clients which will be able to receive communications services from an alternative server (standby server) after the server is switched from a main server (present server) to the alternative server is calculated based on all said check results; the calculated number of clients is compared with the number of clients which are receiving the communications services from the main server prior to the switch, and the appropriateness of the switch is determined based on the result of this comparison; the switch from the main server to the alternative server is controlled based on the result of the determination.

Abstract: A distributed processing system which enables a plurality of computers to make quick access to a shared storage unit. A storage quota management unit manages storage quotas, which limit the total amount of data that each user can store on the shared storage unit. When a write request to the shared storage unit is issued at a certain computer, a user identification unit identifies the requesting user. Then a free quota calculation unit calculates the remaining free storage quota of the identified user. A reserve space allocation unit allocates an appropriate reserve space to the computer according to the remaining free storage quota, allowing the computer to use the allocated reserve space at its discretion to handle the user's data write request.