Abstract: In a storage apparatus recording the writing operation of data as journal information, it was necessary to fully overwrite the data to be newly written over the previously written data in order to reduce the journal information. Further, when journal information is reduced, it was not possible to perform accurate recovery in incremental steps. Journal information is separated into journal data information in block units, and journal log information including map information for referring to such journal data information, and this is stored in a journal storage area. When there is journal log information in which block contents of the journal data information coincide, the map information of the new journal log information is rewritten to refer to a block in which the contents to be referred to by the map information of the old journal log information coincide.

Abstract: A congestion control system provided in a connection portion between a network for an Internet provider and the Internet estimates a processing capability of a Web server on the basis of states of TCP/IP such as a window size of connection being connected, a cancellation rate of packet, a response time, a throughput and the like in a congestion state of the Web server to be requested and a network to the Web server and calculates a regulation duration for each Web server on the basis of the processing capability and the number of clients being in a waiting state for a re-request to the Web server so that the client is regulated when a response for regulating the re-request with the regulation duration is returned to the client. Consequently, since the number of re-requests per unit time can be made fixed, congestion due to re-requests can be prevented and the user can necessarily utilize the Web server upon re-request.

Abstract: Provided is a bandwidth control method for a computer system that includes: at least one storage system; a plurality of host computers connected to the storage system via a network; and a management computer connected to the host computers, the method including the steps of: monitoring a state of the host computers; judging whether or not the each host computer is in a priority state in which operation of the host computer needs to be given priority over other host computers; communicating over a priority bandwidth when it is judged that the host computer is in a priority state; and communicating, when it is judged that the host computer is not in a priority state, over a non-priority bandwidth, which corresponds to one of a part and an entirety of a bandwidth remaining after allocating priority bandwidths to other host computers that are in a priority state.

Abstract: A management system accepts a connection request from a client computer to a server computer, acquires connection settings information, calculates a network bandwidth required for processing for connection from the client computer to the server computer, stores the connection request into a connection request processing queue, determines whether the processing for the connection from the client computer to the server computer can be performed or not, and notifies the client computer of a server identification number. The client computer issues a connection request to the server computer based on the received server identification number, and starts communication therewith. In spite of concentration of connection requests from a large number of client computers to server computers, the connection requests can be processed while controlling the communication data volume generated in a network at a point where the server computers are aggregated, so as to avoid occurrence of congestion.

Abstract: A method and an apparatus for storing a copy of memory-mapped I/O (MMIO) register are provided for enhancing data processing efficiency. In a structure in which data processing is executed by associating a plurality of logical processors with a physical processor by timing sharing, a host OS stores copy information, namely, shadow, of the MMIO register corresponding to a logical processor in memory both in an active state where a physical processor is allocated to a logical processor corresponding to a guest OS and in an inactive state where no physical processor is allocated to a logical processor. This structure enables a guest OS to gain faster access to the MMIO register through the shadow by memory access, instead of a direct access to the MMIO register, so as to achieve efficient data processing.

Abstract: A search system that can easily search documents while ensuring the security is provided. A computer system includes one or a plurality of client devices, a search server, and a storage server connected to each other via a communication channel, and conducts search in response to a search request from one client device. The storage server stores a disk image that allows the client device to perform a boot operation via a network, thereby providing data search service to the client device.

Abstract: A computer transmits a boot request to a gateway server, and the gateway server, upon receipt of the boot request from the computer, receives boot data stored in a storage server using an upper protocol for security-enhanced communications, and transmits the boot data to the computer using a lower protocol for speed-oriented communications. Upon receipt of the boot data from the gateway server, the computer boots up using the received boot data.

Abstract: When a client-server system that adopts a Web service featuring dynamic connection among different systems is constructed, an existing priority control device therein disconnects communication with lower priority, at the time of server overload that continues for several hours. Thus, the availability of the system is reduced. A client-server Web service system includes a unit for interpreting communication protocols at a protocol layer 4 used in the system, a unit for receiving requests transmitted from clients to a server, for buffering, a unit for analyzing the protocol type, the destination, and the communication contents of each of the requests, a unit for converting the result of the analysis into a priority, and a unit for transmitting the buffered requests to the server based on the priority and then transmitting to the clients responses from the server.

Abstract: A congestion control and avoidance method including a method check step of determining whether the request contents is cacheable or uncacheable on the basis of the request inputted from the client terminal, a first Uniform Resource Identifier (URI) check step of, when it is determined that the request contents is cacheable in the method check step, checking a URI included in the request from the client terminal to determine whether the request contents is cacheable or uncacheable, a first URI hash search step of, when it is determined that the request contents is cacheable based on determination of the first URI check step, searching a URI hash to determine to execute any of regular caching, priority caching and access limitationing operation, and a step of executing any of the regular caching, priority caching and access limitationing operation according to determination in the first URI hash search step.

Abstract: A congestion control and avoidance method including a method check step of determining whether the request contents is cacheable or uncacheable on the basis of the request inputted from the client terminal, a first Uniform Resource Identifier (URI) check step of, when it is determined that the request contents is cacheable in the method check step, checking a URI included in the request from the client terminal to determine whether the request contents is cacheable or uncacheable, a first URI hash search step of, when it is determined that the request contents is cacheable based on determination of the first URI check step, searching a URI hash to determine to execute any of regular caching, priority caching and access limitationing operation, and a step of executing any of the regular caching, priority caching and access limitationing operation according to determination in the first URI hash search step.

Abstract: A method for handling data packets in a relay device that is provided in a network comprises receiving a data packet including a packet header and packet data from a first client, the data packet identifying a second client to which the data packet is to be directed, the packet header including a first source address identifying the first client; associating the first source address to a second source address, the second source address obtained from one of a plurality of addresses assigned to the relay device; and transmitting the data packet to the second client after writing the second source address to the packet header of the data packet.

Abstract: The request from the client to the server is made through the traffic control apparatus. The traffic control apparatus includes a unit for controlling the request from the client, a unit for judging the data reception performance of the client and a unit for controlling the number of clients simultaneously connected to the server. The number of simultaneous connections in the server is controlled so that the resource of the server can be utilized sufficiently and the requests in number exceeding the performance of the server cannot be transferred. When it is expected that it takes time longer than a fixed time to provide the service to be required to the client, the request is rejected and when it is expected that the service can be provided within the fixed time, the request is received.

Abstract: A proxy server for storing contents data extracted from a contents packet received from a stream server as cache data of stream contents into a cache file and transferring the received packet to a contents requester after rewriting the address of the received packet, having a function for requesting the stream server to stop providing service of the stream contents and requesting another proxy server to transfer the remaining portion of the stream contents.

Abstract: The present invention relates to an optical fiber device having a structure for effectively restraining the splice loss from increasing between two kinds of optical fibers having respective mode field diameters different from each other. The optical fiber device comprises first and second optical fibers fusion-spliced to each other, which are partly heat-treated such that both of their respective ratios of change in mode field diameter in the longitudinal direction become a predetermined value or less after fusion-splicing. When the ratios of change in mode field diameter in the vicinity of the fused point are appropriately controlled as such, the increase in splice loss at the fused point between the first and second optical fibers is effectively suppressed.

Abstract: A proxy response apparatus 1 is equipped with a module that obtains and retains request messages and response messages exchanged between a client 3 and main and backup servers 2a and 2b, a module for detecting a failure in the main server 2a, a module for sending to the backup server 2b requests retained when a failure occurs in the main server 2a, a module for receiving responses from the backup server 2b, a module for detecting communications status between the client 3 and the main server 2a at the time the failure occurred, and a module for responding in place of the main server 2a in order to resume communicating state from the previous state.

Abstract: An optical fiber splicing method capable of fully reducing the splice loss at room temperature is provided. In the optical fiber splicing method in accordance with the present invention, respective end faces of optical fibers are fused together in a splicing step (S101). In a condition setting step (S102), a set value &agr;0 is set. Thereafter, a heating step (S103), a measuring step (S104), and a termination determining step (S105) are carried out repeatedly. In the heating step, a region including the fusion-spliced point is heated under a predetermined heating condition. In the measuring step, splice loss is measured. In the termination determining step, the splice loss &agr;n measured in the measuring step and the set value &agr;0 set in the condition setting step are compared with each other in terms of magnitude.

Abstract: A congestion control system provided in a connection portion between a network for an Internet provider and the Internet estimates a processing capability of a Web server on the basis of states of TCP/IP such as a window size of connection being connected, a cancellation rate of packet, a response time, a throughput and the like in a congestion state of the Web server to be requested and a network to the Web server and calculates a regulation duration for each Web server on the basis of the processing capability and the number of clients being in a waiting state for a re-request to the Web server so that the client is regulated when a response for regulating the re-request with the regulation duration is returned to the client. Consequently, since the number of re-requests per unit time can be made fixed, congestion due to re-requests can be prevented and the user can necessarily utilize the Web server upon re-request.

Abstract: A congestion control and avoidance method including a method check step of determining whether the request contents is cacheable or uncacheable on the basis of the request inputted from the client terminal, a first URI check step of, when it is determined that the request contents is cacheable in the method check step, checking a URI included in the request from the client terminal to determine whether the request contents is cacheable or uncacheable, a first URI hash search step of, when it is determined that the request contents is cacheable based on determination of the first URI check step, searching a URI hash to determine to execute any of regular caching, priority caching and access limitationing operation, and a step of executing any of the regular caching, priority caching and access limitationing operation according to determination in the first URI hash search step.

Abstract: An optical fiber splicing method capable of fully reducing the splice loss at room temperature is provided. In the optical fiber splicing method in accordance with the present invention, respective end faces of optical fibers are fused together in a splicing step (S101). In a condition setting step (S102), a set value &agr;0 is set. Thereafter, a heating step (S103), a measuring step (S104), and a termination determining step (S105) are carried out repeatedly. In the heating step, a region including the fusion-spliced point is heated under a predetermined heating condition. In the measuring step, splice loss is measured. In the termination determining step, the splice loss &agr;n measured in the measuring step and the set value &agr;0 set in the condition setting step are compared with each other in terms of magnitude.

Abstract: The present invention relates to an optical fiber device having a structure for effectively restraining the splice loss from increasing between two kinds of optical fibers having respective mode field diameters different from each other. The optical fiber device comprises first and second optical fibers fusion-spliced to each other, which are partly heat-treated such that both of their respective ratios of change in mode field diameter in the longitudinal direction become a predetermined value or less after fusion-splicing. When the ratios of change in mode field diameter in the vicinity of the fused point are appropriately controlled as such, the increase in splice loss at the fused point between the first and second optical fibers is effectively suppressed.