Abstract: In a mainframe class data processing system having multiple logical partitions and a port to a network, a host-network interface is established for reducing network overhead at the multiple partitions. The host-network interface includes, for example, a host channel connection coupling the multiple partitions of the host system to a communications adapter having a network device driver for each network coupled to the adapter. The adapter also includes an address resolution protocol (ARP) cache designed to hold predetermined media headers for the clients coupled to the network(s) for use in forwarding an internet protocol (IP) datagram across the network to one of the clients from a partition of the host system. If not predetermined, the adapter is provided with a capability to dynamically determine the needed media header for transmission of the IP datagram across the network to the client. In Ethernet format, this dynamically determining includes forwarding an Ethernet 802.

Abstract: In a mainframe class data processing system having multiple logical partitions and a port to a network, a host-network interface is established for reducing network overhead at the multiple partitions. The host-network interface includes, for example, a host channel connection coupling the multiple partitions of the host system to a communications adapter having a network device driver for each network coupled to the adapter. The adapter also includes an address resolution protocol (ARP) cache designed to hold predetermined media headers for the clients coupled to the network(s) for use in forwarding an internet protocol (IP) datagram across the network to one of the clients from a partition of the host system. If not predetermined, the adapter is provided with a capability to dynamically determine the needed media header for transmission of the IP datagram across the network to the client. In Ethernet format, this dynamically determining includes forwarding an Ethernet 802.

Abstract: A technique for statically linking an application process to a wrapper library employed in intercepting one or more calls invoked by the application process. The intercepted calls may comprise system calls or library calls. In a first link step, the application process is statically linked with at least the intercept library, and in one embodiment, all libraries associated with the application process except for the wrapper library. This first statically linking step creates a first module. Thereafter, at least one call invoked by the application process, and to be intercepted by the intercept library, is renamed. The renaming of the intercepted call is from its original name to a temporary name in the standard program library, the intercept library and the application program. This renaming step creates a second module that no longer contains the original name of the at least one intercepted call.

Abstract: A hybrid non-uniform-memory-architecture/simple-cache-only-memory-architecture (NUMA/S-COMA) memory system and method are described useful in association with a computer system having a plurality of nodes coupled to each other. The plurality of nodes include NUMA memory which are configured to store data lines. The NUMA memories include a NUMA coherence subsystem for coordinating transfer of data between the nodes. At least one S-COMA cache is provided on at least one node of the computer system. The at least one S-COMA cache is configured to employ the NUMA coherence subsystem in sending data communication to or receiving data communication from another node of the plurality of nodes of the computer system. Data stored at another node of the system is accessed using a home node real address as the network address. The home node real address is translated into a local real address at the client node using a boundary function translation table.

Abstract: A method and program product for a distributed system having a plurality of nodes and a switch network for passing messages between nodes, each message being sent from a source node to a target node. Each node is connected to the switch network by an adapter having a count register for adding the value of the packets in messages received by the adapter to the value in the count register and a threshold register for containing a desired threshold value. An interrupt generator generates interrupts when the value in the count register is equal to or greater than the value in the threshold register. The value in the threshold register may be changed under program control to enable or disable interrupts.

Abstract: A checkpoint of a process is taken in order to provide a consistent state of the process in the event the process is to be restarted. When the process is restarted, the process is placed in the state it was in when the checkpoint was taken. However, there are times when certain information has changed since the last checkpoint and it should not be restored. For example, if a process is restarted on a computing unit different from the one in which the checkpoint is taken, then various attributes associated with external data referenced by the process (e.g., an address to an external function/variable) might be different than at the time of the checkpoint. Similarly, even on the same computing unit, if the functions and/or variables are reloaded, the attributes may be different. Since these new attribute values are needed for the restarted process, they should not be restored. In order to prevent restoration of the attributes, only part of the Data Section is restored.

Abstract: A method for remotely administering one or more nodes of a distributed data processing system to provide mirroring of operating system images, and/or designating of alternate volume groups for the one or more nodes. A new data class is defined in a system data repository (SDR) coupled to a control node of the distributed system. A set of commands are provided to initiate and discontinue mirroring from the control node on a nodal volume group, along with designating alternate volume groups for remote installation on one or more nodes of the system in parallel. An interface to add, delete, modify or display information about nodal volume groups is also provided.

Abstract: A technique for remotely administering one or more nodes of a distributed data processing system to provide mirroring of operating system images, and/or designating of alternate volume groups for the one or more nodes. A new data class is defined in a system data repository (SDR) coupled to a control node of the distributed system. A set of commands are provided to initiate and discontinue mirroring from the control node on a nodal volume group, along with designating alternate volume groups for remote installation on one or more nodes of the system in parallel. An interface to add, delete, modify or display information about nodal volume groups is also provided.

Abstract: A system for remotely administering one or more nodes of a distributed data processing system to provide mirroring of operating system images, and/or designating of alternate volume groups for the one or more nodes. A new data class is defined in a system data repository (SDR) coupled to a control node of the distributed system. A set of commands are provided to initiate and discontinue mirroring from the control node on a nodal volume group, along with designating alternate volume groups for remote installation on one or more nodes of the system in parallel. An interface to add, delete, modify or display information about nodal volume groups is also provided.

Abstract: A write-behind enablement approach is presented which allows writing data to multiple volumes of storage media associated with one or more server nodes in a distributed processing environment. A client application on a client node writes blocks of data to a first magnetic tape of a first server node until an end of physical storage of the first magnetic tape is reached, without having predetermined the size of the first magnetic storage. Thereafter, the writing of blocks of data is switched to a second magnetic tape, which may be on the first server node or a second server node in the system. The writing and switching process can repeat a number of times across multiple magnetic tapes. Data is written in a write-behind operation and the switching to a new magnetic tape occurs transparent to the client application, and without loss of data.

Abstract: Record-based backward skipping is provided for accessing logical records contained within physical blocks of data of a storage medium. A computing unit coupled to the storage medium reads a current block of data from the storage medium and determines a number of logical records within the current block, as well as the location of each logical record. The number of logical records is then employed to determine whether the desired logical record is within the current block, and if so, a pointer is provided to the desired logical record for skipping back to that record. If the desired logical record is not within the current block, then a previous block is read from the storage medium and the process is repeated to determine whether the desired logical record is within the new block.

Abstract: Record-based backward skipping is provided for accessing logical records contained within physical blocks of data of a storage medium. A computing unit coupled to the storage medium reads a current block of data from the storage medium and determines a number of logical records within the current block, as well as the location of each logical record. The number of logical records is then employed to determine whether the desired logical record is within the current block, and if so, a pointer is provided to the desired logical record for skipping back to that record. If the desired logical record is not within the current block, then a previous block is read from the storage medium and the process is repeated to determine whether the desired logical record is within the new block.

Abstract: Record-based backward skipping is provided for accessing logical records contained within physical blocks of data of a storage medium. A computing unit coupled to the storage medium reads a current block of data from the storage medium and determines a number of logical records within the current block, as well as the location of each logical record. The number of logical records is then employed to determine whether the desired logical record is within the current block, and if so, a pointer is provided to the desired logical record for skipping back to that record. If the desired logical record is not within the current block, then a previous block is read from the storage medium and the process is repeated to determine whether the desired logical record is within the new block.

Abstract: A write-behind computer program product is presented which allows writing data to multiple volumes of storage media associated with one or more server nodes in a distributed processing environment. A client application on a client node writes blocks of data to a first magnetic tape of a first server node until an end of physical storage of the first magnetic tape is reached, without having predetermined the size of the first magnetic storage. Thereafter, the writing of blocks of data is switched to a second magnetic tape, which may be on the first server node or a second server node in the system. The writing and switching process can repeat a number of times across multiple magnetic tapes. Data is written in a write-behind operation and the switching to a new magnetic tape occurs transparent to the client application, and without loss of data.

Abstract: A method, system, and associated program code and data structures are provided for a message processing system in which messages are transmitted from source nodes to destination nodes. An “eager” rendezvous transmission mode is disclosed in which early arrival buffering is provided at message destination nodes for a predetermined amount of data for each of a predetermined number of incoming messages. Relying on the presence of the early arrival buffering at a message destination node, a message source node can send a corresponding amount of message data to the destination node along with control information in an initial transmission. Any remaining message data is sent only upon receipt by the source node of an acknowledgement from the destination node indicating that the destination node is prepared to receive any remaining data.