Abstract: An approach for optimizing a copying of a data object in a concurrent copying garbage collection operation is provided. In an embodiment, a source copy of the data object to be copied as part of the garbage collection operation is identified. A copying of the source copy to a target location is initiated by a primary accessing thread. This initiating of the copying includes the creation of a temporary target object header for the target object in the target location that contains an indicator set to indicate that the copying is ongoing. As the copying is occurring, the execution of any other accessing threads that are attempting to use the data object are held for as long as the indicator indicates that the copying is ongoing. Once the copying has completed, the target object header is replaced with a copy of the source object header, resetting the indicator.

Abstract: Disclosed herein are embodiments for performing multi-version concurrency control (MVCC) in non-volatile memory. An embodiment operates by determining that an event occurred, wherein one or more write transactions to one or more records of a multi-version database that were pending prior to the event did not commit. The one or more write transactions are identified based on a commit value that was stored in the non-volatile memory prior to the event. A particular one of the identified uncommitted write transactions is selected. From the multi-version database, a first version of a record corresponding to the selected uncommitted write transaction that was not committed, and an earlier version of the record that was committed prior to the event are identified. A visibility of the record is set to indicate that the earlier version of the record is visible and the first version of the record is not visible.

Abstract: An intelligent conflict detection system. The system provides semantic expression of edits and history-aware conflict detection in a large-scale service allowing multiple users to simultaneously work with the same document, which may result in conflicting edits. When submitted, changes to a version of a document are compared to all versions of the document created since the document was sourced. Edits to documents are expressed as intents describing the changes in terms of an action and object of that action based on a characteristic of the data being edited. Comparing the intent of current edits against the historical intent of the edits made in prior versions originating from the same source document allows the system to intelligently assess whether the edits are in conflict. History-aware semantic analysis results in users being prompted less frequently to resolve conflicts, which improves the user experience.

Abstract: An example method of managing memory includes identifying a first object of the first type to update, the first object being stored on a heap. The method also includes reading a first memory address stored in a second object of the second type and storing a copy of the first object at a second memory address. The first memory address is an initial memory address of the first object. The method further includes after the copy is stored, reading a third memory address stored in the second object. The third memory address is a current memory address of the first object. The method also includes determining whether the first memory address matches the third memory address, and when the first memory address is determined to match the third memory address, updating the first memory address stored in the second object with the second memory address.

Abstract: A system and method for storing and providing metadata. Metadata may be retrieved from multiple sources. The metadata is stored in facets in a repository and tagged to indicate one or more of the source, a time frame, or an associated data object. In response to receiving a request for metadata, a system selects metadata based on the specified object, source, or time frame. Access permissions corresponding to the requester are used to select and provide metadata for which the requester has permissions.

Abstract: A computer-implemented method and system for performing garbage collection in a delta compressed data storage system selects a file recipe to traverse to identify live data chunks and selects a chunk identifier from the file recipe. The chunk identifier is added to a set of live data chunks. Delta references in the file metadata corresponding to the chunk identifier are added to the set of live data chunks. Data chunks in a data storage system not identified by the set of live data chunks are then discarded.

Abstract: An apparatus, system, and method are disclosed for data block usage information synchronization for a non-volatile storage volume. The method includes referencing first data block usage information for data blocks of a non-volatile storage volume managed by a storage manager. The first data block usage information is maintained by the storage manager. The method also includes synchronizing second data block usage information managed by a storage controller with the first data block usage information maintained by the storage manager. The storage manager maintains the first data block usage information separate from second data block usage information managed by the storage controller.

Abstract: A method to schedule garbage collection operations may be executed in a client/server system using multiple servers. The method includes comparing usage of memory in respective ones of the plurality of servers to one or more memory usage thresholds and dynamically identifying one or more servers in which to perform garbage collection of memory objects during a particular time period. By distributing the durations over which garbage collection is performed on respective servers, the client server system, among other things, reduces the pauses in servicing client requests.

Abstract: A system and method for performing garbage collection. A system includes a storage medium, a first table including entries which map a virtual address to locations in the storage medium, and a second table with entries which include a reverse mapping of a physical address in a data storage medium to one or more virtual addresses. A storage controller is configured to perform garbage collection. During garbage collection, the controller is configured to identify one or more entries in the second table which correspond to a segment to be garbage collected. In response to determining the first table includes a valid mapping for a virtual address included in an entry of the one of the one or more entries, the controller is configured to copy data from a first location identified in the entry to a second location in the data storage medium, and reclaim the first storage location.

Abstract: A memory system includes a nonvolatile semiconductor memory having blocks, the block being data erasing unit; and a controller configured to execute; an update processing for; writing superseding data in a block, the superseding data being treated as valid data; and invalidating superseded data having the same logical address as the superseding data, the superseded data being treated as invalid data; and a compaction processing for; retrieving blocks having invalid data using a management tablet the management table managing blocks in a linked list format for each number of valid data included in the block; selecting a compaction source block having at least one valid data from the retrieved blocks; copying a plurality of valid data included in the compaction source blocks into a compaction target block; invalidating the plurality of valid data in the compaction source blocks; and releasing the compaction source blocks in which all data are invalidated.

Abstract: An illustrative embodiment of a computer-implemented process for dynamic measurement and adaptation of a parallel copying garbage collector initializes values and data structures, receives an evacuate set, determines whether a new copy block is required and responsive to a determination that a new copy block is required, calculates a size of the new copy block. The computer-implemented process further selects a survivor region from a list of survivor regions to form a selected survivor region, places a lock on the selected survivor region, identifies a number of threads enqueued on the selected survivor region, responsive to a determination that a contention value exceeds a predetermined value, increases a size of the list of survivor regions, evacuates blocks to the selected survivor region and responsive to a determination that more evacuate blocks do not exist, terminates.

Abstract: In an object-relocating garbage collector, objects are copied and new copies taken into use concurrently with mutator execution without needing to use a read barrier, and importantly, without requiring verification (read-back) of each copied word and without requiring atomic instructions for the copying. Write barriers, thread-local write barrier buffers and processing them by the garbage collector, and write propagation are used for achieving this.

Abstract: A method and system for flushing physical memory blocks in a memory device is disclosed. The method includes detecting a quantity of available memory, background flushing partially obsolete memory blocks if the quantity decreases to a background activation threshold, disabling the background flushing if the quantity increases to a background deactivation threshold, foreground flushing the partially obsolete memory blocks if the quantity decreases to a foreground activation threshold, and disabling the foreground flushing if the quantity increases to a foreground deactivation threshold. The thresholds may be adaptively defined. The background flushing may occur when the host interface is idle. The foreground flushing may interleave writing operations with flushing operations while a write command is unfinished.

Abstract: A system and method for efficient garbage collection. A general-purpose central processing unit (CPU) partitions an allocated heap according to a generational garbage collection technique. The generations are partitioned into fixed size cards. The CPU marks indications of qualified dirty cards during application execution since the last garbage collection. When the CPU detects a next garbage collection start condition is satisfied, the CPU sends a notification to a special processing unit (SPU) corresponding to a determination of one or more card root addresses, each card root address corresponding to one of said marked indications. The SPU has a single instruction multiple data (SIMD) parallel architecture and may be a graphics processing unit (GPU). The SPU may utilize the parallel architecture of its SIMD core to simultaneously compute multiple card root addresses. Following, the SPU sends these addresses to the CPU to be used in a garbage collection algorithm.

Abstract: A method of automatically defining a new class in a class hierarchy includes creating a descendent class that descends from one or more specified ancestor classes; sequentially analyzing each class along each inheritance path from the specified ancestor classes to a specified similar class to identify each class item in each class that is not selected from the specified ancestor classes; storing a respective pointer for each class item identified in each class that is not inherited by the class referencing the class item and associated with the class; storing a respective pointer for each class item identified in each class that is inherited and redefined by the class referencing the class item and being associated with the class if a pointer referencing the class item is not already stored; and copying each class item referenced by a stored pointer to the descendent class.

Abstract: Persistent memory in an integrated circuit cars (ICC) must be managed in such a way that removal of power from the device at any moment does not leave the data stored in this memory in a faulty or inconsistent state. The mechanisms of this disclosure accomplish this end using the tag-length-value data structures found extensively in ICC software and standards.

Abstract: A method and apparatus for obtaining a real time media stream provided as a plurality of media fragments from a plurality of remote nodes in a communications network. A first series of media fragments satisfying a first selection criterion is requested from a first remote node and a further series of media fragments satisfying a further different selection criterion is requested from at least one further remote node. When combined, the first series of fragments and the further series of fragments provide the complete media stream.

Abstract: A method and apparatus for obtaining a real time media stream provided as a plurality of media fragments from a plurality of remote nodes in a communications network is described. Media fragments are requested from the plurality of remote nodes. A series of media fragments is received from at least one of the plurality of remote nodes. A selection criterion is determined for identifying the series of data fragments, and a blocking request is sent to at least one other of the plurality of remote nodes, the blocking request instructing the at least one other node to block the media fragments satisfying the selection criterion from being sent.

Abstract: An apparatus, system, and method are disclosed for managing data with an empty data segment directive at the requesting device. The apparatus, system, and method include a token directive generation module and a token directive transmission module. The token directive generation module generates a storage request with a token directive. The token directive includes a request to store on the storage device a data segment token. The token directive substitutes for a series of repeated, identical characters or a series of repeated, identical character strings to be stored as a data segment. The token directive includes at least a data segment identifier and a data segment length. The data segment token and the token directive are substantially free from data of the data segment. The token directive transmission module transmits the token directive to the storage device.

Abstract: A file management method includes creating a rotation group by grouping a file group in which the generations of the files are managed by changes in the file names, and storing information of the rotation group in a rotation group management unit; acquiring file identification information of the files belonging to the rotation group from the file group according to the information of the rotation group, and storing the file identification information in a file identification information management unit; and acquiring file identification information of the rotation group from the file identification information management unit, further acquiring file identification information of the files belonging to the rotation group from the file group according to the information of the rotation group, and comparing the acquired pieces of file identification information.

Abstract: Methods and systems for garbage collection are described. In some embodiments, Garbage collector threads may maximize local accesses and minimize remote access by copying Young objects and Old objects differently. When copying a Young object, a garbage collector thread may determine the lgroup of the pool that contains the object and copy the object to a pool of the same lgroup. The garbage collector thread may spread Old objects among lgroups by copying Old objects to pools of the same lgroup as the respective garbage collector thread. Additional methods and systems are disclosed.

Abstract: System and Methods for non-uniform memory (NUMA) garbage collection are provided. Multiple memories and processors are categorized into local groups. A heap space is divided into multiple pools and stored in each of the memories. Garbage collection threads are assigned to each of the local groups. Garbage collection is performed using the garbage collection threads for objects contained in the pools using the garbage collector threads, memory, and processor assigned to each local group, minimizing remote memory accesses.

Abstract: During garbage collection, writes to objects being copied (relocated) are monitored (tracked) using a write barrier that uses a thread-local write barrier buffer. In the preferred embodiment, soft synchronization is used for reading the thread-local write barrier buffers. In response to detecting a write to an object, the object may be re-copied, the copying may be made to fail, the write may be propagated to another copy of the object, or, e.g., another node in a distributed system may be notified of the write.

Abstract: Methods, systems, and software for notification of multi-function peripheral (MFP) receive jobs are disclosed. A system provides a MFP configured to store at least one remote communication identifier, to process a MFP job associated with the at least one remote communication identifier, and to transmit, in response to an event associated with the MFP job, notification directed to the remote communication identifier. The MFP may receive the remote communication identifiers from embedded MFP jobs or may receive them from previously stored user profiles that specify notification preferences for different job types. The remote identification identifier may be, for example, an email address or a telephone number.

Abstract: A method, an article of manufacture, and system for heapifying an object. The method includes: storing, in a working set, a first address of a certain object in a stack frame, copying the certain object into the heap area and holding a second address of the certain object in the heap area, following each stack frame to find a pointer pointing to the first address stored in the working set, converting the address that the pointer points to into the second address, proceeding to a next stack frame, where the address conversion includes storing an address of another object in the working set if the converted address is stored as a value of a field of the other object in the stack frame, and terminating the process in response to a lack of pointers found in the stack frame to point to the addresses stored in the working set.

Abstract: A system of the present invention includes a storage device for distinguishably storing old objects that are objects having existed for not less than a predetermined period since being generated and new objects that are objects having existed for less than the predetermined period since being generated. Then, a new object that has existed for less than the predetermined period since being generated is selected from the storage device, and an old object having the same content as the selected new object is searched for. If such an old object is not found, the selected new object is newly stored as an old object in the storage device. If the old object is found, a reference to the selected new object is integrated with a reference to the found old object. If the old object is stored, the reference to the selected new object is changed to a reference to the stored old object.

Abstract: A memory management method and a system for performing garbage collection. The method includes the steps of providing in a memory space a heap partitioned into a plurality of areas including an area for object allocation and a To area for future object allocation. In garbage collection, an object reachable from a root set among objects allocated in the area of use is copied into the To area. In addition, a finalizable object among the objects allocated in the area of use is set as a finalization target. Here, the finalizable object is an object unreachable from the root set and has a finalize method. After the garbage collection is completed, the finalizable object of finalization target allocated in the area of use is finalized.

Abstract: A garbage collection algorithm that achieves hierarchical copy order with parallel garbage collection threads. More specifically, the present invention provides a garbage collection method and system for copying objects from a from-space to a to-space. The method comprises the steps of (a) having multiple threads that simultaneously perform work for garbage collection (GC), (b) examining the placement of objects on blocks, and (c) changing the placement of objects on blocks based on step (b). Preferably, the method includes the additional step of calculating a placement of object(s) based on step (b), and using the result of the calculation for step (c). For example, the calculation may be used to increase the frequency of intra-block pointers and/or to increase the frequency of siblings on the same block.

Abstract: An architecture and system are described that provide a unified file access service within in a managed computing environment composed of diverse networks, computing devices, and storage devices. The service provides mechanisms for remotely accessing the file systems of any managed computer or disk snapshot, independently of the computer's current state (powered on, suspended or powered off), its location within the environment, its hardware type (virtual vs. physical), its operating system type, and its file system formats. The system isolates centralized FPAs from the details of clients, proxies and storage elements by providing a service that decomposes offloaded file system access into two steps. A FPA or a requester acting on behalf of the FPA first expresses the disk set or the computer containing the file systems it wishes to access, along with requirements and preferences about the access method.

Abstract: Persistent memory in an integrated circuit cars (ICC) must be managed in such a way that removal of power from the device at any moment does not leave the data stored in this memory in a faulty or inconsistent state. The mechanisms of this disclosure accomplish this end using the tag-length-value data structures found extensively in ICC software and standards.

Abstract: The present invention provides a system that facilitates performing concurrent garbage collection. During operation, the system executes a first mutator thread. While executing the first mutator thread, the system performs a garbage-collection operation using a garbage-collector thread. Performing the garbage-collection operation involves: discovering a live object in a from-space, which is being collected; creating a copy of the live object to a to-space, where live objects are copied to during garbage collection; and replacing the live object in the from-space with a forwarding pointer which points to a location of the copy of the live object in the to-space.

Abstract: In an object-relocating garbage collector, objects are copied and new copies taken into use concurrently with mutator execution without needing to use a read barrier, and importantly, without requiring verification (read-back) of each copied word and without requiring atomic instructions for the copying. Write barriers, thread-local write barrier buffers and processing them by the garbage collector, and write propagation are used for achieving this.

Abstract: A garbage collector is disclosed that permits extensive separation of mutators and the garbage collector from a synchronization perspective. This relative decoupling of mutator and collector operation allows the garbage collector to perform relatively time-intensive operations during garbage collection without substantially slowing down mutators. The present invention makes use of this flexibility by first conservatively determining which objects in a set of regions of interest are live, then planning where to copy the objects (preferably including clustering), and finally performing the actual copying.

Abstract: During garbage collection, writes to objects being copied (relocated) are monitored (tracked) using a write barrier that uses a thread-local write barrier buffer. In the preferred embodiment, soft synchronization is used for reading the thread-local write barrier buffers. In response to detecting a write to an object, the object may be re-copied, the copying may be made to fail, the write may be propagated to another copy of the object, or, e.g., another node in a distributed system may be notified of the write.

Abstract: A garbage collection algorithm that achieves hierarchical copy order with parallel garbage collection threads. More specifically, the present invention provides a garbage collection method and system for copying objects from a from-space to a to-space. The method comprises the steps of (a) having multiple threads that simultaneously perform work for garbage collection (GC), (b) examining the placement of objects on blocks, and (c) changing the placement of objects on blocks based on step (b). Preferably, the method includes the additional step of calculating a placement of object(s) based on step (b), and using the result of the calculation for step (c). For example, the calculation may be used to increase the frequency of intra-block pointers and/or to increase the frequency of siblings on the same block.

Abstract: A method and system for garbage collection are provided. A memory allocation request is received for an object. An object identifier is generated for the object. A first memory location is allocated to the object. A translation table is generated storing a map of the object identifier and the first memory location. A data structure is generated for the object. A mark flag is set based on the number of references of the object. Data stored in the first memory location is moved to a second memory location based upon the value of the mark flag. The data is deleted from the first memory location based upon a value of the mark flag.

Abstract: Methods and systems are described for implementing mass amendments that affect many line items and span many entries in a trade compliance system. Mass amendment functions allow a data field that is repeated in a plurality of records in the trade compliance system to be corrected without redundant data entry. A copy of the records that contain the data field is made. The copy may be exported into an external spreadsheet. A global edit, which makes the same correction in each repetition of the data field, is performed on the copy. The edited copy is uploaded into a database in the trade compliance system, to update the records while still preserving the data that existed in the data field prior to the global edit.

Abstract: In a non-volatile memory array, scheduling of reclaim operations to occur before a shortage of erased blocks arises avoids extended periods of reclaim that could exceed a time limit. A memory controller uses information regarding the data stored in the memory array to estimate the additional host data that may be programmed and the reclaim operations to be performed and schedules the reclaim operations to be evenly distributed between write operations until the memory is full.

Abstract: A technique for applying hardware transaction memory to an arbitrarily large data structure is disclosed. A data updater traverses the data structure to locate an update point using a lockless synchronization technique that synchronizes the data updater with other updaters that may be concurrently updating the data structure. At the update point, the updater performs an update on the data structure using a hardware transactional memory transaction that operates at the update point.

Abstract: A method and apparatus are disclosed for restoring a virtual disk (vdisk) in a data storage system as the vdisk was at an earlier time. Pointers are maintained to point to data represented by the vdisk. The pointers are saved to persistent storage at the earlier time. The data at the earlier time is maintained on the data storage device. A pointer pointing to data represented by the vdisk at a later time is compared with the pointers saved at the earlier time. If the pointer from the later time matches the pointer saved at the earlier time, keeping the pointer from the later time in the active file system. If the pointer from the later time does not match the pointers saved at the earlier time, copying a set of pointers associated with the pointer saved at the earlier time to the active file system.

Abstract: A garbage collection algorithm that achieves hierarchical copy order with parallel garbage collection threads. More specifically, the present invention provides a garbage collection method and system for copying objects from a from-space to a to-space. The method comprises the steps of (a) having multiple threads that simultaneously perform work for garbage collection (GC), (b) examining the placement of objects on blocks, and (c) changing the placement of objects on blocks based on step (b). Preferably, the method includes the additional step of calculating a placement of object(s) based on step (b), and using the result of the calculation for step (c). For example, the calculation may be used to increase the frequency of intra-block pointers and/or to increase the frequency of siblings on the same block.

Abstract: A system and method is provided for efficiently pinning references to the managed heap. The system and method allow for references to managed objects to be declared as pinned during a call to unmanaged code. The references are then reported as pinned to a garbage collector in response to invocation of a garbage collection service. The reference can be declared as pinned by a programmer within the source code or automatically invoked at run-time based on an unsafe condition. The garbage collection service will not move or relocate objects that are referenced by the active pinned local variables. If a garbage collection does not occur, the fact that the local variables are declared pinned is ignored.

Abstract: A system and method is provided for efficiently pinning references to the managed heap. The system and method allow for references to managed objects to be declared as pinned during a call to unmanaged code. The references are then reported as pinned to a garbage collector in response to invocation of a garbage collection service. The reference can be declared as pinned by a programmer within the source code or automatically invoked at run-time based on an unsafe condition. The garbage collection service will not move or relocate objects that are referenced by the active pinned local variables. If a garbage collection does not occur, the fact that the local variables are declared pinned is ignored.

Abstract: Described is a technology by which a real-time data relocating mechanism is provided for multiprocessing environments, including supporting lock-free programs that run in parallel. The relocating mechanism moves an object by using a status field related to the data field, possibly in an interim (wide) object space, which is then copied to a to-space object. The status information for each data field of the original object contains information indicating where a current version of the data for each field is present, that is, in the original, wide or to-space object. In one example, a handshake mechanism of a garbage collector establishes preparation and copy phases between the mechanism and other threads that determine where memory accesses occur. Also described is support for program thread compare-and-swap (CAS) operations and/or multi-word atomic operations.

Abstract: The disclosure and claims herein are directed to efficient journaling for recovery of a database index by journaling zones of a page. A journal mechanism maintains a page zone bit map that includes a bit for a plurality of zones in each page to indicate which zones have had their unchanged image journaled before being changed since a last sync point update. The page zone bit map has a bit for each zone in each page so that the status of each zone can be tracked separately. Tracking the smaller zones of the pages makes the process more efficient both at run time and during recovery by reducing the period of time for memory deposits and reducing the amount of total redundant/recovery data sent to disk for larger pages.

Abstract: A cyclic commit protocol is used to store relationships between transactions and is used by the technology to determine whether a transaction is committed or not. The protocol allows creation of a cycle of transactions which can be used to recover the state of a storage device after a host failure by identifying the last committed version of intention records as committed or uncommitted based on the data stored in the physical pages.

Abstract: An eager reference-counting garbage collection system performs a static analysis on the intermediate representation of a program. The system then uses liveness information to inject eager reference-counting updates into the program. Through the use of the liveness information, reference-counting decrements can be made earlier in execution than in traditional reference-counting schemes, freeing up memory more efficiently. Additionally, a reference-counting subsumption optimization tool identifies redundant reference-counting updates and removes them, lowering the number of garbage collection update calls and improving execution throughput. Reference-counting subsumption can also be used as a throughput enhancer in traditional reference-counting schemes that maintain up-to-date tallies of references from the stack.

Abstract: Directories in a file system are defined with a dummy cluster in a file allocation table as the initial entry. Subsequent clusters in a directory's definition may define any data for the directory that can be changed in a transaction-safe mode. A directory may be modified in a transaction-safe mode by modifying any of the subsequent clusters while tracking changes in a second file allocation table. When the changes have been made to the directory, a pointer to the second file allocation table may be switched to indicate that the second file allocation table is now last known good. The first file allocation table may then be synchronized with the second.