Abstract: A transmitting apparatus is provided for transmitting data to a receiving apparatus, the transmitting apparatus comprising: a first network interface configured to transmit data to the receiving apparatus over a first communications path; a transmit buffer forming part of the first network interface, the transmit buffer being configured to store a series of packets of data for transmission over the first communications path; a data compression module configured to compress at least some of the packets of data stored for transmission; a second network interface configured to receive a decompression rate value from the receiving apparatus over a second communications path; and wherein the apparatus is configured to select data packets stored in the transmit buffer for compression based on a compression rate value and a transmission rate value of the transmitting apparatus and a decompression rate value received from the receiving apparatus via the second network interface.

Abstract: A method comprises: initialising a value of an input transfer size parameter; initialising a value of a transfer data segment parameter; requesting data from a data source; storing the data in a cache; using the value of the transfer data segment parameter to form a data segment; transmitting the data segment using multiple logical connections of a transfer path deleting the data segment from the cache; measuring performance of transmission of data over the path and identifying a first optimum value of the transfer data segment parameter; measuring performance of transmission of data over the path and identifying a first optimum value of the input transfer size parameter; measuring performance of transmission of data over the path and identifying a second optimum value of the transfer data segment parameter; and requesting data from the data source using the first optimised value of the input transfer size parameter.

Abstract: Apparatus has at least one processor and at least one memory having computer-readable code stored therein which when executed controls the at least one processor to perform a method comprising: maintaining plural logical connections on a communications path; transmitting data packets on different ones of the logical connections; monitoring acknowledgements received in respect of the data packets transmitted over the different ones of the logical connections; reusing a logical connection for which an acknowledgement for a transmitted data packet has been received; creating a new logical connection when there is a data packet to transmit over the path and there are no logical connections available for reuse; and destroying excess logical connections. This can result in the maintenance and use of a number of logical connections that is most appropriate for the link conditions and the data transmission requirements, thereby potentially maximizing transmission speed and minimizing system resource requirements.

Abstract: A system comprises: a first network node (3); a second network node (4); at least one communication path (702, 703) connecting the first network node to the second network node; a first cache (706) forming part of the first network node; and a second cache (705) forming part of the second network node, wherein: the first cache is configured to cache data received from a host; the first network node is configured to transmit the data from the first cache to the second network node over the at least one communication path; the second network node is configured to receive the data transmitted by the first network node and to store the received data in the second cache prior to providing the data from the second cache to a connected device; the second network node is configured to use operating parameters of the second cache to calculate a hunger parameter representative of the capability of the second cache to receive more data; the second network node is configured to communicate the hunger parameter to the

Abstract: Apparatus comprises: first and second transmitter interfaces, each configured to transmit data over a respective communications path including one or more logical connections; first and second transmit buffers forming part of the first and second transmitter interfaces respectively, the first and second transmit buffers being configured to store packets of data for transmission over their respective communication path; one or more path capability determining modules configured to determine a measure of capability of each of the communications paths to transmit data; an input data buffer configured to store data for provision to the first and second transmit buffers for subsequent transmission; and a data handling module configured to respond to determining the presence of data in the input buffer for transmission by: using the measured capabilities of the communication paths and measures of the quantity of data stored in the transmit buffers to select one of the first and second transmitter interfaces for

Abstract: Apparatus has at least one processor and at least one memory having computer-readable code stored therein which when executed controls the at least one processor to perform a method comprising: causing each of first and second transmitter interfaces to transmit data over a respective communications path including one or more logical connections; and causing each of first and second transmission parameter calculating modules, associated respectively with the first and second transmitter interfaces, to perform: monitoring the transmission of data over its respective communications path, using results of monitoring the transmission of data over its respective communications path to calculate a path speed value for transmitting data over its respective communications path, and causing the path speed value to be used in the transmission of data over its respective communications path.

Abstract: Apparatus has at least one processor and at least one memory having computer-readable code stored therein which when executed controls the at least one processor to perform a method comprising: maintaining plural logical connections on a communications path; transmitting data packets on different ones of the logical connections; monitoring acknowledgements received in respect of the data packets transmitted over the different ones of the logical connections; reusing a logical connection for which an acknowledgement for a transmitted data packet has been received; creating a new logical connection when there is a data packet to transmit over the path and there are no logical connections available for reuse; and destroying excess logical connections. This can result in the maintenance and use of a number of logical connections that is most appropriate for the link conditions and the data transmission requirements, thereby potentially maximizing transmission speed and minimizing system resource requirements.

Abstract: Apparatus comprises: first and second transmitter interfaces (702, 711), each configured to transmit data over a respective communications path (702, 703) including one or more logical connections; first and second transmit buffers forming part of the first and second transmitter interfaces respectively, the first and second transmit buffers being configured to store packets of data for transmission over their respective communication path; one or more path capability determining modules (709, 713) configured to determine a measure of capability of each of the communications paths to transmit data; an input data buffer (706) configured to store data for provision to the first and second transmit buffers for subsequent transmission; and a data handling module (704) configured to respond to determining the presence of data in the input buffer for transmission by: using the measured capabilities of the communication paths and measures of the quantity of data stored in the transmit buffers to select one of the fi

Abstract: A bridging system, comprising bridges and a network, is arranged to transfer data using TCP/IP or similar between a local Storage Area Network (SAN) and a remote SAN. In one embodiment, a bridge is arranged to transfer data from a plurality of ports in a periodic sequence. While an acknowledgement from the remote SAN for data transferred from one port data is awaited, further data can be transferred using one or more of the remaining ports. In other embodiments, one or more parameters, such as number of ports, Receive Window Size etc., can be optimised using artificial intelligence (AI) routines in order to control the data transfer rate between the bridges. The bridging system may be configured to perform a self-learning routine on installation and, in some embodiments, to compile and consult a knowledge base storing optimum configurations for transferring data packets having different attributes by simulating data transfers.

Abstract: A wrapper operates to store data relating to messages received from a kernel such that kernel-specific data or information is not passed to a module core. The wrapper on receiving data from the module core uses the data stored in the relevant part of the memory to provide the data or information required by the kernel to handle the message. On receiving a message, the kernel begins to process it. At a certain point the wrapper intercepts the message and creates a SCSI data message and a PLUT element comprising a kernel pointer, a core pointer, and a reference counter. The kernel pointer is provided by the kernel and identifies a memory location where implementation-specific information pertaining to the message, pointers to raw data and a SCSI-formatted command descriptor block resides. The reference counter defines the number of times a message will be processed within the core before the related memory can be reused. The wrapper re-formats data and references the result by the core pointer.

Abstract: A bridging system, comprising bridges 3, 4 and network 5, is arranged to transfer data using TCP/IP or similar between a local Storage Area Network (SAN) 1 and a remote SAN 2. In one embodiment, the bridge 3 is arranged to transfer data from a plurality of ports 12-1˜12-n in a periodic sequence. While an acknowledgement from SAN 2 for data transferred from one port 12-1 data is awaited, further data can be transferred using one or more of the remaining ports 12-2˜12-n. In other embodiments, one or more parameters, such as number of ports, Receive Window Size etc., can be optimised using artificial intelligence (AI) routines in order to control the data transfer rate between the bridges 3, 4. The bridging system may be configured to perform a self-learning routine on installation and, in some embodiments, to compile and consult a knowledge base storing optimum configurations for transferring data packets having different attributes by simulating data transfers.

Abstract: A bridge includes first and second network connections, and processor means and memory together operating to implement plural software modules. These allow data to be passed between the network connections and allow the data to be handled as it passes. Each software modules has a priority, either pre-set in software or settable by the bridge in response to receiving a command from a device connected to the bridge. The bridge is operable to arrange the software modules sequentially between the network connections, such that data provided by a software module is received at the next software module in the sequence, according to their priorities. Software modules can be added to or removed from the sequence. This can be carried out dynamically, for instance by the bridge following a determination from monitoring of data flow that such would improve performance.

Abstract: A library partitioning module (LPM) is configured to connect multiple hosts to a tape library. The LPM comprises at least two host input/outputs, each for connection to a respective host; and a library input/output for connection to the library. The LPM is an interface between hosts and a tape library such that it allow several hosts to access the library as if they have sole use of the library's resources. The modification of requests includes intercepting SCSI messages between robot and host and translating/transforming them. At least one tape slot for each host is allocated as a virtual import/export location. When a host sends a command to move a tape between a driver or a tape slot and an import/export location, the request is modified by the LPM so that movement occurs instead between a virtual import/export slot allocated to that host. This avoids conflicts involving the import/export location resources of the library.

Abstract: A wrapper operates to store data relating to messages received from a kernel such that kernel-specific data or information is not passed to a module core. The wrapper on receiving data from the module core uses the data stored in the relevant part of the memory to provide the data or information required by the kernel to handle the message. On receiving a message, the kernel begins to process it. At a certain point the wrapper intercepts the message and creates a SCSI data message and a PLUT element comprising a kernel pointer, a core pointer, and a reference counter. The kernel pointer is provided by the kernel and identifies a memory location where implementation-specific information pertaining to the message, pointers to raw data and a SCSI-formatted command descriptor block resides. The reference counter defines the number of times a message will be processed within the core before the related memory can be reused. The wrapper re-formats data and references the result by the core pointer.

Abstract: In a bridge, a cache module is operable on receipt of a message pertaining to a write or other cacheable command from an initiator device to process the command so as to cause a suitable command to be passed to the relevant target device and to respond immediately to the initiator device with a ‘response good’ response. The ‘response good’ response is sent to the initiator device before the corresponding response pertaining to the cacheable command is received from the target device. When the cache module receives an error response from a target device, the cache module converts the response into a ‘deferred error’ response and passes this onwards to the initiator device. Since the initiator device receives a positive response sooner, it can send a subsequent command sooner and thus performance is increased.

Abstract: A bridge includes first and second network connections, and processor means and memory together operating to implement plural software modules. These allow data to be passed between the network connections and allow the data to be handled as it passes. Each software modules has a priority, either pre-set in software or settable by the bridge in response to receiving a command from a device connected to the bridge. The bridge is operable to arrange the software modules sequentially between the network connections, such that data provided by a software module is received at the next software module in the sequence, according to their priorities. Software modules can be added to or removed from the sequence. This can be carried out dynamically, for instance by the bridge following a determination from monitoring of data flow that such would improve performance.