Abstract: Embodiments of the present invention are directed to a method and apparatus for receiving an input/output (I/O) request from a host computer that specifies an operation to be performed on a content addressable storage (CAS) system and determining which operation is specified by the request before receipt of the I/O request by a content addressable storage system. In another embodiment, an I/O request from a host computer is received by a first CAS which determines if the request is to be processed by another CAS system. When it is determined that the request is to be processed by another CAS system, the first CAS system may forward the request to the other CAS system. In another embodiment, an appliance receives an I/O request from a host computer to perform an operation that accesses a unit of content. The appliance may set up a communication session between the host and a CAS system so that the unit of content may be transmitted between the host and the CAS system without passing through the appliance.

Abstract: The invention provides a system whereby both queues and objects/services in a messaging system can be located via the same mechanism (message clustering).

Abstract: A method and apparatus for managing a migration of a data set from at least one first storage location to at least one second storage location, wherein read requests to the data set from at least one application program executing on a computer system initially are serviced from the at least one first storage location. The data set is copied from the at least one first storage location to the at least one second storage location, and then at least one aspect of the computer system is modified so that read requests to the data set are serviced from the at least one second storage location to achieve the migration. In one embodiment, the migration is subsequently undone by modifying the at least one aspect of the computer system so that read requests to the data set are again serviced from the at least one first storage location. In another embodiment, after the migration is performed, a determination is made as to whether to finalize the migration.

Abstract: Methods and apparatus for performing a data migration in a clustered computer system. In one aspect, the availability of the data being migrated is maintained during the migration. In another aspect, a data set is migrated by a transfer utility in one of the hosts in the cluster, and in response to a failure of the host, the migration is resumed without restarting from the beginning point of the data set. In a further embodiment, the hosts in the cluster have agents associated therewith to manage the data migration, and prior to taking at least one action associated with the data migration, the agents coordinate to ensure that the hosts in the cluster are prepared to have the at least one action taken.

Abstract: Methods and apparatus for migrating a data set. In one embodiment, a migration is paused. In another embodiment, for a migration of data between multiple source/target groups, the migration is initiated by beginning transfer for some groups and queuing others for later processing. In a further embodiment, different transfer vehicles are used for different source/target groups. In a still further embodiment, a transfer vehicle is automatically selected for at least one source/target group.

Abstract: One embodiment is directed to a method in a computer system including a host computer and at least one storage system including first and second storage volumes, the host computer including at least one application program executing thereon. The method comprises acts of intercepting and redirecting an access request from the at least one application program to the first storage volume to the second storage volume. Other embodiments are directed to a computer readable medium with instructions for performing the method, a host computer with at least one controller to intercept and redirect the access request. Other aspects are directed to methods in a computer system including a host computer, a first storage system including a first storage volume, and a second storage system including a second storage volume, wherein the second storage volume is a hardware mirror of the first storage volume.

Abstract: The invention relates to a subscriber for indicating liveness to a broker in a multicast publish/subscribe messaging system comprising the broker and a plurality of subscribers. The subscriber, having seen an indication of liveness, sets a timer. If the subscriber sees an indication of liveness prior to the expiry of the timer, then the subscriber cancels the timer. However if an indication of liveness is not seen by the subscriber prior to the expiry of its timer, then the subscriber sends its own indication of liveness to the broker.

Abstract: A variety of techniques are disclosed for efficient liveness monitoring in a reliable publish/subscribe multicast system having at least one broker and at least one subscriber, by: at the broker, sending (310) a status request message to the subscriber, and at the subscriber, sending (350) a status response message to the broker to indicate liveness. Status responses by subscribers may be suppressed when at least a chosen minimum number (>=1) of subscribers send a response. This suppression (320-340) uses a system of “response claim” messages and random back-off timers. These provide the advantage that the efficiency of network usage is improved by reducing the number of unwanted packets that are sent.

Abstract: The invention provides a system whereby both queues and objects/services in a messaging system can be located via the same mechanism (message clustering).

Abstract: A translator-compiler for converting legacy architecture. In the area of management software or distributed management software, a standard architecture is evolving from legacy or proprietary architecture, and the standard embraces CIM/XML (Common Information Model/eXtensible Markup Language) computer language. Many vendors have developed proprietary languages for their respective management products that are incompatible with such standard. To accomplish compatibility between standard architecture and various different proprietary architectures, a substantial amount of code must be written at great effort and expense, unless an automatic, easily-applied and universal solution can be achieved. A translator-compiler is disclosed which meets these solution criteria and therefore solves this incompatibility problem. Flowcharts depicting algorithms along with sample input and output code in C++, as well as an example of the final XML result are also disclosed.

Abstract: An arrangement and method for flow composition model searching by holding in a repository (120) records (130) of flow composition models containing information representative of predetermined flow composition model characteristics thereof, specifying (200) information representative of desired ones of the predetermined flow composition model characteristics, and retrieving from the repository flow control model records matching the specified information. The FCM characteristics may include Message Flow, Work Flow and Connector characteristics. The specified information may include wild card characters. This provides the advantage that a new specification of flow characteristics, derived from the general model FCM, is used. Hence using it enables the application of search, reuse, compare, etc., on any present and future FCM realization.

Abstract: A method for physically executing parallel operations in a resource manager (10) while retaining the effect of a defined logical serial ordering is provided. A plurality of operations is applied by a client application (16, 17, 18) to the resource manager (10). The method includes commencing a transaction between the client application (16, 17, 18) and the resource manager (10). The resource manager (10) receives a plurality of operations from the client application (16, 17, 18) in a logical order. The client application (16, 17, 18) indicates to the resource manager (100 that these operations can be applied in parallel. The resource manager (10) implements the operations in parallel and controls the parallel operations to ensure that the plurality of operations is executed such that the result of the parallel execution is the same as the result that would have been achieved by serial execution in the logical order. The transaction then ends.

Abstract: A method and system for processing a request to retrieve data from a database is disclosed. The method of the present invention comprises receiving the request which comprises a function that processes at least one data item specified in the request, retrieving the at least one data item from a database, and invoking the function. When the function is invoked, at least one parameter comprising information related to the at least one data item is passed to the function. Thus, a function can be written independently of the data which they are called to process.

Abstract: Provided are rule-based methods, apparatus and computer programs for configuration checking and management in integrated data processing systems. A plurality of components of a system output configuration information (for example to one or more repositories), and a control tool accesses the output configuration information and applies configuration rules including consistency rules to check for consistency between the configuration information for the plurality of components. The results of the consistency check are then displayed on a display screen. The components can be a plurality of heterogeneous, federated components which are configured to interoperate within a data processing system or network. The configuration information of one component can include binding references to resources of other federated components.

Abstract: A method and system (200) for message handling in a messaging system by: receiving messages from applications associated with transactions and placing the received messages in a queue (230) for subsequent retrieval; receiving requests of prepare, commit and abort for the transactions; deferring retrieval of messages from the queue so as to occur in the same sequence as the prepare requests of the transactions with which the respective messages are associated; and retrieving from the queue messages associated with a transaction in the order in which the messages were put by the application. Preferably deferral is achieved by deferring completion of transaction commits as required to occur in the same order as the prepare message requests.

Abstract: A method for handling data in a plurality of data storage disks having user data sectors and corresponding parity sectors, the method being used when the disks are being operated in a non-degraded or a degraded mode wherein a non-volatile RAM is used in an array control processor which controls the operation of such disks. When new data is to be written into the array, the non-volatile RAM stores information identifying the array, the starting sector into which data is to be written and the number of sectors to be used for writing the new data so that parity and data entries in corresponding sectors can be matched when a power failure occurs. Further, when opening a new array, the data and parity entries in corresponding sectors can be matched and verified, the operation for such matching being performed in between other operations that are being performed by the control processors (i.e., in the "background" thereof).

Abstract: A method for providing on-line replacement of a module which is at a specified position in an array of modules connected to a common control processor so that all other modules in the array can continue operating during the replacement operation. When the module is removed an indication is provided to the control processor showing that removal has occurred and identifying the position thereof. When the replacement has occurred an indication thereof is provided to the control processor, the replacement module is tested, and the state of the replacement module is updated to place it in the same state it would have been in if it had not been replaced.

Abstract: A method for handling data in a plurality of data storage disks having user data sectors and corresponding parity sectors, the method being used when the disks are being operated in a degraded mode wherein data in sectors of an inoperative user data disk are reconstructed from data in the corresponding sectors of the other user data disks and the corresponding parity entry. The reconstructed user data in a user data sector of the inoperative disk is written into the corresponding parity sector in place of the parity entry therein, before any new data is written into the corresponding sector of an operative disk. Information identifying the inoperative disk is written into a specified identification region of the parity disk to indicate that such operation has occurred. The new data is then written into the corresponding sector of the operative disk.

Abstract: A solid modelling system for generating a spatial representation of an object defined by a structure having a plurality of linked nodes representing the object in terms of solid geometric primitives combined by a logical expression, which is adapted to recognize redundant primitives automatically. Bitmap generation logic (BGL) is provided for traversing at least certain of the nodes in the structure for generating a bitmap representing the part of the logical expression defined in the traversed nodes and redundant primitive logic (RPL) is provided for testing the bitmap for logical redundancies indicative of redundant geometric primitives. Each bit in the bitmap is representative of a respective one of the constituents of the primitives, a constituent being the volume formed by the intersection of primitives or their complements, and, in order to test for the redundancy of a primitive u, the RPL tests for equivalence of the corresponding utrue and ufalse constituents in the bitmap.

Abstract: The generation of NRZ representations of RLL encoded datastreams utilizes a length oriented arithmetically recursive RLL encoder whose finite state encoding transition space has assigned RLL symbols to state transitions. By constraining the paths, and hence restricting the set of allowable RLL symbol streams, then selectable notch frequencies in the spectra of the NRZ representation can be secured. Recovery of data is obtained by the logical dual of this process. Also, a NRZ bit stream representation exhibits a frequency spectrum notched at f/kn Hertz if k NRZ source codestreams are k-way interleaved.