Abstract: In a multinode data processing system capable of partitioning operations a method is provided for adding nodes to a configuration of nodes in a manner which node quorums are employed but in which two quorum values (ideal and enforced) are employed and in which old nodes using a given file system are distinguished from new nodes. The method prevents even the transient use of inappropriate quorum values.

Abstract: A built-in self test system for testing a clock and data recovery circuit. The present invention provides a built-in self test circuit which operates with high speed phase lock loop. The built-in circuit comprises data generating means for generating a test data byte and serializing means coupled to the data generating means for converting the test data byte into serial test data. The clock and data recovery means are coupled to the output of the serializing means for recovering the clock and test data from the serial test data. A deserializing means coupled to the output of the clock and data recovery means converts the recovered serial test data into a recovered test data byte, and analyzing means connected to the output of the deserializing means compares the recovered test data byte to the initial test data byte.

Abstract: A model for computer resources based on type and amount is employed in a consistent manner across several layers in a data processing system as a mechanism for providing users with significantly more control over the allocation, utilization and scheduling of resources for user's software applications running on the target computer system.

Abstract: A system, method and computer readable medium for providing a snapshot of a subset of a file system. A first snapshot of a first set of source files in a file system is generated. The first snapshot includes an inode corresponding to each source file in the first set of files. Stored in each inode is a first identifier associated with the first set of files and a second identifier associated with the time of the first snapshot. Next, a second snapshot of a second set of source files is taken. The second snapshot includes an inode corresponding to each source file in the second set of files. Stored in each inode are a first identifier and a second identifier. Subsequent snapshots are taken every first period and every second period for the first set of files and the second set of files, respectively.

Abstract: Space is allocated on data storage devices in proportion to weights associated with the storage devices. The weights can be dynamically adjusted at any time in order to accommodate changes in the system and to better utilize the storage devices. The technique used to perform the allocating is independent of the weights used by the allocating. Further, the allocation technique can accommodate general purpose data streams having varying lengths and/or varying access patterns, as well as special purpose data streams, such as video streams.

Abstract: Sockets of a computing environment are optimally tuned, even though the environment is dynamic. The tuning is based on information dynamically determined at the time a socket is opened. The information includes, for instance, application specific information and/or socket specific information. Based on the information, one or more parameters of the socket, such as a socket send buffer size and/or a socket receive buffer size, are set to reflect the current configuration of the environment.

Abstract: A system and method is provided for synchronizing time of day information between and among communication adapters. Time of day information, which is desired for proper message packet ordering and delivery, is recovered in a process in which a master adapter, connected to a master node, periodically broadcasts current time of day information to slave adapters which operate to determine whether or not drift correction is to be applied.

Abstract: Concurrent access to data is managed through concurrency control techniques. Various types of techniques are employed to manage the access, including locking-based techniques and non-locking-based techniques. A dynamic switch from one type of concurrency control technique (e.g., a locking-based technique) to a different type of concurrency control technique (e.g., a non-locking-based technique) is enabled. This switching is based on access patterns and/or application requirements for each file. The switching allows enhanced performance for both coarse-grain sharing and fine-grain sharing of data.

Abstract: The management and use of replicated distributed transactions is facilitated. A distributed synchronous transaction system protocol is provided to manage the replication of distributed transactions for client application instances. The distributed synchronous transaction system allows transactions to be replicated without having the client application instances be aware of other instances to receive the transaction. Further, if a failure occurs during processing of a distributed replicated transaction, the distributed synchronous transaction system manages the recovery of the failure.

Abstract: The management and use of replicated distributed transactions is facilitated. A distributed synchronous transaction system protocol is provided to manage the replication of distributed transactions for client application instances. The distributed synchronous transaction system allows transactions to be replicated without having the client application instances be aware of other instances to receive the transaction. Further, if a failure occurs during processing of a distributed replicated transaction, the distributed synchronous transaction system manages the recovery of the failure.

Abstract: An embodiment of the present invention is directed to a method for compiling, storing, and interpreting, as often as needed, a representation of any MPI datatype, including the steps of compiling a tree representation of an MPI datatype into a compact, linear data gather scatter program (DGSP) wherein the DGSP is of a form general enough to encode an arbitrarily complex datatype, registering the compact linear DGSP with a communications subsystem for later interpretation by the subsystem for at least one of sends, receives, packs and unpacks, creating a registered DGSP, and interpreting the registered DGSP. In one embodiment of the present invention, the form of the DGSP uses a single generalized representation. In another embodiment the single generalized representation covers any of the arbitrarily complex datatype patterns that can arise in this context.

Abstract: A method and system unbind a rise/fall tuple of a VHDL generic variable and create rise time and fall time generics of each generic variable that are independent of each other. Then, according to a predetermined correlation policy, the method and system collect delay values in a VHDL standard delay file, sort the delay values, remove duplicate delay values, group the delay values into correlation sets, and output an analysis file. The correlation policy may include collecting all generic variables in a VHDL standard delay file, selecting each generic variable, and performing reductions on the set of delay values associated with each selected generic variable.

Abstract: Various components are provided to manage a clustered environment. These components include a System Registry that provides a global data storage; a Configuration manager that stores data locally on nodes of the clustered environment and globally within the System Registry; a Liveness component to provide status of communications paths of the cluster; a Group Services component that provides services to one or more other components of the clustered environment; and a Resource Management component that communicates with one or more resource controllers of the clustered environment. Each of the components of the clustered environment has one or more data and/or functional dependencies on one or more other components of the environment. However, relationships between the components are created such that the data and functional dependencies form an acyclic graph (i.e., a cycle of dependency relationships is avoided).

Abstract: The modular exponentiation function used in public key encryption and decryption systems is implemented in a standalone engine having at its core modular multiplication circuits which operate in two phases which share overlapping hardware structures. The partitioning of large arrays in the hardware structure, for multiplication and addition, into smaller structures results in a multiplier design which includes a series of nearly identical processing elements linked together in a chained fashion. As a result of the two-phase operation and the chaining together of partitioned processing elements, the overall structure is operable in a pipelined fashion to improve throughput and speed. The chained processing elements are constructed so as to provide a partitionable chain with separate parts for processing factors of the modulus. In this mode, the system is particularly useful for exploiting characteristics of the Chinese Remainder Theorem to perform rapid exponentiation operations.

Abstract: Various components are provided to manage a clustered environment. These components include a System Registry that provides a global data storage; a Configuration manager that stores data locally on nodes of the clustered environment and globally within the System Registry; a Liveness component to provide status of communications paths of the cluster; a Group Services component that provides services to one or more other components of the clustered environment; and a Resource Management component that communicates with one or more resource controllers of the clustered environment. Each of the components of the clustered environment has one or more data and/or functional dependencies on one or more other components of the environment. However, relationships between the components are created such that the data and functional dependencies form an acyclic graph (i.e., a cycle of dependency relationships is avoided).

Abstract: A method for transparently handling messages originating from local shared memory and from an external source. A device driver allows the local sender to identify and wake up a waiting receiver task thread, simulating a packet arrival hardware interrupt. Upon awakening, the receiver task thread examines both shared memory and hardware message queues. The method can use a software routine that simulates handling of an occurrence of a hardware interrupt. The method invokes a local notify system service module that passes a window number identifying a receiving task. The method invokes a wake thread module that passes awakens a thread associated with the window number, and examines the shared memory buffer for receipt of the local source message. The method then copies the local source message from the shared memory buffer to the receiving task.

Abstract: An efficient mechanism for sending messages without the use of intermediate copies (i.e. without the staging of data) is provided. In particular an interface specification which allows use users of a transport protocol is defined so as to lend itself to efficient implementations. The interface specification is a complete and robust set of user functions usable within systems desiring reliable and efficient zero copy transport protocols. Two methods are provided to accomplish the implementation of an efficient zero copy protocol. The first method is especially useful in systems where the network device has limited capabilities in terms of hardware, message fragmentation and message reassembly. An additional RDRAM memory allows data to reside in an adapter while handshake operations take place between an adapter and a node so as to specify the final destination of the data. The second method takes advantage of network devices with advanced features which are exploited for maximum efficiency.

Abstract: A method for building a hierarchical multicast tree which is centered around a specific node in an Internet Protocol (IP) communications network. The method on a subnetwork comprising dynamically electing a subnetwork leader node for each subnetwork using multicast communications confined to the subnetwork. Receiving a configuration file containing a list of all the network addresses of the nodes in a network. Receiving a number of permissible connections each subnetwork leader node in the network is permitted with other subnetwork leader nodes. And establishing a multicast connection between each subnetwork leader node as identified in the configuration file so that there is a multicast connection path from each subnetwork leader node for each subnetwork and a subnetwork containing a network leader node. In another embodiment, a system and computer readable medium is disclosed to carry out the above method.

Abstract: The material and geometric properties of an electrical probe contact are combined to produce an electrical contact which is capable of self-alignment over many thousands of uses. The probe contact moves substantially only in a vertical direction and provides a consistent contact force with corresponding electrical contact pads on a semiconductor wafer. The probe contacts are configured in an array of a large plurality of individual contacts which extend from a base to which they are attached through apertures in an overlying mask spaced apart from the base.

Abstract: Communication between different entities of a computing environment is facilitated by an address mapping capability. Messages are sent between the entities to have desired tasks performed. Instead of providing within the messages the actual non-logical addresses (e.g., virtual, real addresses) used to perform the tasks, logical addresses are provided. The logical addresses are then mapped to the non-logical addresses. Each logical address can map to a plurality of non-logical addresses.