Abstract: An improved reader-writer locking for synchronizing access to shared data. When writing the shared data, a writer flag is set and a lock is acquired on the shared data. The shared data may be accessed following the expiration of a grace period and a determination that there are no data readers accessing the shared data. When reading the shared data, the writer flag is tested that indicates whether a data writer is attempting to access the shared data. If the writer flag is not set, the shared data is accessed using a relatively fast read mechanism. If the writer flag is set, the shared data is accessed using a relatively slow read mechanism.

Abstract: A ring-type meter lock comprising a ring, first and second ends on the ring, a lock housing on the first end, a slot in the lock housing, a latch unit in the lock housing, a lock pin on the latch unit enterable and withdrawable from the slot, a tongue on the second end enterable into the slot, an opening in the tongue receiving the lock pin, a key-receiving configuration in the latch unit, and the lock pin being rotatably supported for unlatching of the latch unit.

Abstract: A technique for the dynamic instrumentation of a running software system. One or more callable instrumentation functions are accessible in a first memory space associated with the software system. The one or more callable instrumentation functions are adapted to probe an operation of the software system and return data regarding the probed operation. Probed operation environment information needed by the one or more instrumentation functions is provided to a second memory space associated with the software system. First memory space addresses associated with the probed operation environment information are determined from a resource that is accessible in the second memory space. A probe handler is generated that includes calls to the one or more instrumentation functions with references to the first memory space addresses. The probe handler is callable as part of the probed operation.

Abstract: A technique for realtime-safe detection of a grace period for deferring the destruction of a shared data element until pre-existing references to the data element have been removed. A pair of counters is established for each of one or more processors. A global counter selector determines which counter of each per-processor counter pair is a current counter. When reading a shared data element at a processor, the processor's current counter is incremented. Following counter incrementation, the processor's counter pair is tested for reversal to ensure that the incremented counter is still the current counter. If a counter reversal has occurred, such that the incremented counter is no longer current, the processor's other counter is incremented. Following referencing of the shared data element, any counter that remains incremented is decremented.

Abstract: A manhole cover having an integrated locking system that is self-locking and easy to open. The device includes a cover plate adapted to rest on a manhole cover support surface of a manhole frame so as to be substantially flush with a top portion of the manhole frame and a surrounding surface in which the manhole frame is situated. An anchor on the cover plate is adapted to engage the manhole frame at a first location in a manner that resists lifting of the cover plate proximate to the first location. A locking member on the cover plate is movable between a locked position and an unlocked position. In the locked position, the locking member is adapted to engage the manhole frame at a second location in a manner that resists lifting of the cover plate proximate to the second location. In the unlocked position, the locking member is disengaged from the manhole frame.

Abstract: A system and method of modulating tape tension during operation of a tape drive data storage system in which a fixed position tape guide utilizes one or more drag elements to exert a control force on a tape medium that affects downstream tape tension. Drag elements that may be used include, but are not necessarily limited to, air ports that delivery positive or negative air pressure to the tape medium, skiving edge elements that are positionable into and out of engagement with the tape medium, and brakes or motors that engage the tape guide (if it is rotatably mounted) to control its rotational torque. A tension control circuit is used to vary the operation of the one or more drag elements. Signal inputs to the control circuit are provided by a tape tension sensor adjacent to or incorporated in the tape guide.

Abstract: A system, method and computer program product for atomically moving a shared list element from a first list location to a second list location includes inserting a placeholder element at the second list location to signify to readers that a move operation is underway, removing the shared list element from the first list location, re-identifying the list element to reflect its move from the first list location to the second list location, inserting it at the second list location and unlinking the placeholder element. A deferred removal of the placeholder element is performed following a period in which readers can no longer maintain references thereto. A method, system and computer program product are additionally provided for performing a lookup of a target list element that is subject to being atomically moved from a first list to a second list.

Abstract: A system, method and computer program product for use in a server cluster having plural server nodes implementing a server tier in a client-server computing architecture in order to determine which of two or more partitioned server subgroups has a quorum. A determination is made of relative priorities of the subgroups and a quorum is awarded to the subgroup having a highest relative priority. The relative priorities are determined by policy rules that evaluate comparative server node application state information. The server node application state information may include one or more of client connectivity, application priority, resource connectivity, processing capability, memory availability, and input/output resource availability, etc. The policy rules evaluate the application state information for each subgroup and can assign different weights to different types of application state information. An interface may be provided for receiving policy rules specified by a cluster application.

Abstract: A technique for enhancing the transfer of files from a source network host to a destination network host includes accessing a file stored on the source host from the destination host, caching a local copy of the file on the destination host, and prefetching all remaining files in a file system group of which the file is a member by caching local copies thereof on the destination host.

Abstract: A system and method for exclusion of an aneurysm of an aortic arch region using a graft delivery system capable of maneuvering around an aortic arch, an aortic arch graft, and an occluder system for isolating an aneurysm while occluding one or more corresponding arteries, and with bypass of those arteries being performed using one or more selected bypass grafts. The graft may be branched or branchless. The graft delivery system has a flexible sheath that is manipulated manually with the aid of a guidance system. A hoist delivery system may also be provided. The occluder system may comprise independent occluders with one or more anchor members adjacent to one end. Alternatively, the occluders can be provided as part of the aortic arch graft, either as a built-in singular self-deploying occluder or as built-in multiple occluders. A kit is also provided containing a graft, stents, occluders, and optional delivery system.

Abstract: A structured document storage and management technique utilizes a generic document model tree, a symbol conversion module and an encoded vector set to store structured documents. The generic document model tree represents a structured document model and contains one or more structured document nodes without storing node data unique to any particular structured document. The symbol conversion module contains untagged data associated with the one or more structured document nodes, and representing node data for particular structured documents. The symbol conversion module also maintains a value code in association with each untagged data element. The encoded vector set includes one or more encoded vectors corresponding to the one or more structured document nodes having associated untagged data. Each encoded vector contains one of the value codes at an index position that corresponds to a particular structured document.

Abstract: A method, system and computer program product for modifying data elements in a shared data element group that must be updated atomically for the benefit of readers requiring group integrity. A global generation number is associated with the data element group and each member receives a copy of this number when it is created. Each time an update is performed, the global generation number is incremented and the updated element's copy of this number is set to the same value. For each updated data element, a link is maintained from the new version to the pre-update version thereof, either directly or using pointer-forwarding entities. When a search is initiated, the current global generation number is referenced at the commencement of the search. As data elements in the group are traversed, the reader traverses the links between new and old data element versions to find a version having a matching generation number, if any.

Abstract: A system, method and computer program product for efficient sharing of memory between first and second applications running under first and second operating systems on a shared hardware system. The hardware system runs a hypervisor that supports concurrent execution of the first and second operating systems, and further includes a region of shared memory managed on behalf of the first and second applications. Techniques are used to avoid preemption when the first application is accessing the shared memory region. In this way, the second application will not be unduly delayed when attempting to access the shared memory region due to delays stemming from the first application's access of the shared memory region. This is especially advantageous when the second application and operating system are adapted for real-time processing. Additional benefits can be obtained by taking steps to minimize memory access faults.

Abstract: A security key tool for unlocking and locking a manhole security device that secures a manhole access opening. The security key tool includes a longitudinal body portion and a handle portion. A security key at a first end of the longitudinal portion is adapted to engage a security lock on the security device for actuating a locking mechanism on the security device to an unlocked position. A slidable member may be used to help engage the security key to the security lock or to protect the security key. A latch release tool at a second end of the longitudinal portion is adapted to release a latch on the manhole security device for actuating the locking mechanism to a locked position. Optionally, the latch release tool may be disposed on a tool head that also includes a lifting tool adapted to engage and lift the security device away from a manhole frame after the security device is unlocked.

Abstract: A method, system and computer program product for managing memory allocation among plural virtual application environments supported by a common operating system. The technique may include establishing a mapping between a virtual application environment (or processes therein) and a mapping proxy that is reachable via a reverse mapping pathway adapted to facilitate identification of virtual addresses associated with a memory page frame. The virtual application environment (or processes therein) may be identified as an allocation recipient of the memory page frame by traversing the reversing mapping pathway to the mapping proxy. The memory page frame may be reclaimed for allocation to another virtual application environment by invalidating data therein or transferring the data to a storage resource based upon memory usage by the identified virtual application environment.

Abstract: A system, method and computer program product for intelligent discovery of network information from multiple information gathering agents adapted to discover information concerning the network. The discovery agents each have an associated discovery capability. Based on consideration of the agent discovery capabilities, discovery assignments are computed and network discovery is performed according to the assignments so as to reduce discovery poll overhead.

Abstract: A machine implemented technique for performing dynamic globalization verification testing in a software user interface includes identifying one or more user interface controls in the software user interface having text strings that have been pseudo translated, generating one or more applicable test cases that test for display defects stemming from the pseudo translations, executing the test cases, and logging defects.

Abstract: A technique for efficiently boosting the priority of a preemptable data reader in order to eliminate impediments to grace period processing that defers the destruction of one or more shared data elements that may be referenced by the reader until the reader is no longer capable of referencing the data elements. Upon the reader being subject to preemption or blocking, it is determined whether the reader is in a read-side critical section referencing any of the shared data elements. If it is, the reader's priority is boosted in order to expedite completion of the critical section. The reader's priority is subsequently decreased after the critical section has completed. In this way, delays in grace period processing due to reader preemption within the critical section, which can result in an out-of-memory condition, can be minimized efficiently with minimal processing overhead.

Abstract: A manhole security device for securing a manhole access opening includes a circular barrier adapted to rest on a manhole cover support flange of a manhole frame. Locking members on the barrier are movable between a locked position in which the locking members are adapted to engage the manhole frame and an unlocked position in which the locking members are not adapted to engage the manhole frame. A biasing mechanism on the barrier is adapted to bias each locking member to its locked position. A rotatable locking mechanism on the barrier engages the locking members and has a locking rotational position wherein the locking members are in the locked position and an unlocking rotational position wherein the locking members are in the unlocked position. The locking mechanism has a security lock adapted to receive a security key that applies a rotational torque to the locking mechanism.

Abstract: A method, system and computer program product for avoiding unnecessary grace period token processing while detecting a grace period without atomic instructions in a read-copy update subsystem or other processing environment that requires deferring removal of a shared data element until pre-existing references to the data element are removed. Detection of the grace period includes establishing a token to be circulated between processing entities sharing access to the data element. A grace period elapses whenever the token makes a round trip through the processing entities. A distributed indicator associated with each processing entity indicates whether there is a need to perform removal processing on any shared data element. The distributed indicator is processed at each processing entity before the latter engages in token processing. Token processing is performed only when warranted by the distributed indicator.