Abstract: Methods and arrangements for caching video object portions. A request for stand-alone content in a video object is received, the content neither being cached nor being adjacent to a cached video object portion, and a first portion of the video object is cached. A value is assigned to the first video object portion. A subsequent request for content in the video object is received, the subsequent request corresponding to access to the first video object portion and a second, uncached portion of the video object. The value of the first video object portion is updated. For the second video object portion, an amount to cache and a value are determined.

Abstract: Methods and arrangements for caching video object portions. A request for stand-alone content in a video object is received, the content neither being cached nor being adjacent to a cached video object portion, and a first portion of the video object is cached. A value is assigned to the first video object portion. A subsequent request for content in the video object is received, the subsequent request corresponding to access to the first video object portion and a second, uncached portion of the video object. The value of the first video object portion is updated. For the second video object portion, an amount to cache and a value are determined.

Abstract: Methods and arrangements for caching video object portions. A request for stand-alone content in a video object is received, the content neither being cached nor being adjacent to a cached video object portion, and a first portion of the video object is cached. A value is assigned to the first video object portion. A subsequent request for content in the video object is received, the subsequent request corresponding to access to the first video object portion and a second, uncached portion of the video object. The value of the first video object portion is updated. For the second video object portion, an amount to cache and a value are determined.

Abstract: Methods and arrangements for caching video object portions. A request for stand-alone content in a video object is received, the content neither being cached nor being adjacent to a cached video object portion, and a first portion of the video object is cached. A value is assigned to the first video object portion. A subsequent request for content in the video object is received, the subsequent request corresponding to access to the first video object portion and a second, uncached portion of the video object. The value of the first video object portion is updated. For the second video object portion, an amount to cache and a value are determined.

Abstract: A data storage subsystem includes a volatile memory in which stored data can be denoted as being data that should be preserved in the event of an interruption in the power supply to the volatile memory. The available capacity for such data storage is dynamically allocated between multiple firmware client components of the storage subsystem, such that each client component has its own (varying) allocation of the available capacity. A higher priority for the storage of such data is given to client components on which other client components depend, such as lower layers of the software stack, thereby allowing them to get a larger share of the available capacity for such data storage when needed and complete their input/output requests faster.

Abstract: Provided are a method, system, and article of manufacture for splitting writes between a storage controller and replication engine. A splitter executing in a storage controller manages access to primary volumes. An initialization command is received to communicate with a replication engine. A replication command is received for one primary volume and the primary volume is indicated as subject to replication. A write request is received to write data to a target primary volume of the primary volumes that is indicated as subject to the replication. The data in the write request is written to the target primary volume. The data in the write request is sent to the replication engine. The replication engine executes a copy services function associated with the target primary volume to write the data to a replication engine volume.

Abstract: Provided are a method, system, and article of manufacture for splitting writes between a storage controller and replication engine. A splitter executing in a storage controller manages access to primary volumes. An initialization command is received to communicate with a replication engine. A replication command is received for one primary volume and the primary volume is indicated as subject to replication. A write request is received to write data to a target primary volume of the primary volumes that is indicated as subject to the replication. The data in the write request is written to the target primary volume. The data in the write request is sent to the replication engine. The replication engine executes a copy services function associated with the target primary volume to write the data to a replication engine volume.

Abstract: A mechanism is provided for managing operations in a data storage system. A first storage controller monitors operation state information associated with a plurality of operation states stored in a data structure. The first storage controller detects a change in the operation state information. The change in the operation state information is in response to a managing entity updating the operation state information to a first operation state in the plurality of operation states in the data structure. Responsive to detecting the change in the operation state information, the first storage controller identifies a reference to a first operation associated with the first operation state updated by the managing entity. The first operation is one operation in a plurality of operations. The first storage controller performs the first operation associated with the first operation state.

Abstract: Provided are a method, system, and article of manufacture for splitting writes between a storage controller and replication engine. A splitter executing in a storage controller manages access to primary volumes. An initialization command is received to communicate with a replication engine. A replication command is received for one primary volume and the primary volume is indicated as subject to replication. A write request is received to write data to a target primary volume of the primary volumes that is indicated as subject to the replication. The data in the write request is written to the target primary volume. The data in the write request is sent to the replication engine. The replication engine executes a copy services function associated with the target primary volume to write the data to a replication engine volume.

Abstract: Apparatus for non-disruptive error recovery in a clustered system, comprises a node instance configuration activity quiescing component for quiescing configuration activity at a first virtual node instance; a node instance creation component for creating a second virtual node instance with I/O access blocked; a configuration transfer component for transferring configuration data from the first to the second virtual node instance; a commit component for committing the changeover from the first to the second virtual node instance; a node instance communications blocking component for blocking inbound communications to a first virtual node instance; a node instance communications unblocking component for unblocking I/O access at the second virtual node instance; a communication control component for monitoring outbound communications from the first virtual node instance and signalling completion of all pending outbound communications; and a node instance deletion component for deleting the first virtual node ins

Abstract: A method and apparatus are provided for controlling access to logical units, a logical unit being an addressable entity that accept commands. A plurality of logical units are accessible by one or more ports, a port being an addressable entity that sends commands. A communication means which may be a storage area network (SAN) (102, 202) provides access to the plurality of logical units by the one or more ports. One or more ports that require access to the same logical units are grouped in a named set (301, 302, 303) in a first location. The named set (301, 302, 303) is associated (300) in a subsequent location with selected logical units (304) thereby controlling the access to the logical units. Identification information for the ports in a named set is extracted at the subsequent location by referencing the named set. The sets can be physically defined, for example, by switch zoning, or logically defined by logically grouping port names.

Abstract: Provided are a method, system, and article of manufacture for a replication engine communicating with a splitter to split writes between a storage controller and replication engine. Communication is initiated with the splitter implemented in a storage controller managing access to primary volumes. A command is sent to the splitter to copy writes to one primary volume to the replication engine. Write data is received from the splitter to one of the primary volumes following the splitter receiving the command to copy the writes to the replication engine. A determination is made of a copy services function to use for the received data. The determined copy services function is invoked to transfer the received data to a secondary storage volume.

Abstract: This invention relates to an asynchronous remote copying (ARC) system adapted to operate as a remote copy pair by communicating between primary storage and remote storage of a remote copy pair. The system comprises a primary controller for receiving a write command and writing data to primary storage; a remote controller for receiving a write command and writing data to remote storage; an ARC controller for suppressing the release of the write command to the remote controller if a delay between receiving the write command and the time when the remote storage may accept the data is more than a threshold delay, and the primary controller suppresses recording the data in primary storage until release of the write command to the remote storage.

Abstract: A storage control apparatus, in communication with a cluster of storage devices in a storage network having plural administrator systems, comprises a cluster lock requester component, a cluster lock receiver component and a configuration component, wherein, responsive to receipt of a cluster lock by said cluster lock receiver component, the configuration component is operable to configure a logical resource object within said cluster. The apparatus may also include a cluster lock granter component operable to grant a cluster lock to the cluster lock receiver component responsive to said cluster lock requester component. A method of operating a storage control apparatus includes method steps corresponding to functional components of an apparatus and may be embodied in computer program codes.

Abstract: A copy engine (104) is provided as an interface between firmware (108) and memory space (106) for carrying out copy operations. The copy engine has a first register (202, 203) to point to a first address and a second register (204, 205) to point to a second address. One of the first and second addresses is a source address and one is a destination address for data to be copied. The copy engine (104) also has a control register (201). The control register (201) includes a count of the amount of memory space required by a copy operation, an indication of the direction of the copy operation from the first address to the second address or from the second address to the first address, and an indication of whether the first memory address is incremented or decremented. The copy engine (104) includes a locking mechanism for locking the copy engine (104) during a copy operation. The copy engine (104) also includes a serialization mechanism in which a write is made to control register (201) of zero count.

Abstract: A method and apparatus for relating a device name to a physical location of a device (202) on a network is provided. The network may be a serial loop network, for example a Fibre Channel Arbitrated Loop network. The network includes a plurality of devices (202) on or connected to the network (201) and a control device (205) with control over at least one of the devices (202). Each device (202) has a check output (204) independent of the network (201) with connection means (206) to a control device (205). The method includes the step of sending a device name from the check output (204) of a device (202) to the control device (205). The check output (204) of a device (202) is also connected to an external indication means for indicating the failure of the device (202).

Abstract: According to one general embodiment of the present invention, there is provided a computer program product for reducing incidence of errors in connections between a power consumer apparatus operable to draw a load and a power supply apparatus capable of varying the power supplied, the computer program product comprising: a computer readable storage medium having computer readable program code embodied therewith, the computer readable program code comprising: computer readable program code configured to generate at the power consumer apparatus an identifiable pattern in a load to be drawn from a power supply connection to a power supply apparatus; and computer readable program code configured to monitor at the power consumer apparatus for a change in the load corresponding to the pattern, the monitoring being performed across a signal connection to the power supply apparatus; wherein a positive result of the monitoring indicates a correct configuration. Additional embodiments are also presented.

Abstract: According to a first general aspect of the present invention, there is provided a logic arrangement for reducing incidence of errors in connections between a power consumer apparatus and a power supply apparatus, the logic arrangement comprising: a pattern-generating component for generating an identifiable pattern in a load to be drawn from a power supply connection to a power supply apparatus; and a testing component for monitoring across a signal connection to the power supply apparatus, the testing component monitoring for a change in the load corresponding to the pattern. A positive result of the testing by the testing component indicates a correct configuration. Additional embodiments are also presented.

Abstract: A storage adapter for use in a data storage subsystem includes a controlling processor, a volatile memory, and a nonvolatile memory “dump device.” The storage adapter also includes a battery that can be used to provide sufficient power to the storage adapter to allow data from the volatile memory to be written to the nonvolatile memory of the storage adapter under the control of the processor in the event of an interruption or failure in the main power supply to the storage adapter, i.e. to preserve data stored in the volatile memory in that event. The processor uses the current state of charge of the battery to determine the amount of data that can be “dumped” to the nonvolatile dump device before the battery is depleted.

Abstract: An arrangement and method for update of configuration cache data in a disk storage subsystem in which a cache memory (110) is updated using two-phase (220, 250) commit technique. This provides the advantage that known changes to the subsystem do not require an invalidate/rebuild style operation on the cache. This is especially important where a change will invalidate the entire cache.