4267 results about "Waste collection" patented technology

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.

A pump system for applying negative pressure to a wound, including a flow monitor capable of detecting a deviation from a reference airflow rate provided by a controlled leak to determine whether the system is operating normally or abnormally, and a flow status annunciator to indicate a normal operating condition or whether an abnormal condition is a leak or an occluded line in the system. The pump system further includes a pressure controller for regulating operation of a pump to control pressure in the system at a range around a user-selected setpoint. The pump system may also include a waste collector and a level sensor for detecting when the collector is full.

A technique is provided for reducing the number of write barriers executed in mutator code without compromising garbage collector performance. Advantageously, a compiler generates two forms of a mutator code—a first version with write barriers and a second version substantially without write barriers. In operation, the first version of the code may be accessed by a vtable in a “mature” near-class and the second version may be accessed by a vtable in a “nascent” near-class. According to the invention, mapping of functionally equivalent points in the first and second versions of the mutator code may be facilitated by an associated pcmap. Further, each of the first and second versions may also be associated with a respective nr_map that facilitates mapping functionally equivalent points within different branches of guard code sequences corresponding to reference-writes to non-receiver objects.

An optimized redundant array of solid state devices may include an array of one or more optimized solid-state devices and a controller coupled to the solid-state devices for managing the solid-state devices. The controller may be configured to globally coordinate the garbage collection activities of each of said optimized solid-state devices, for instance, to minimize the degraded performance time and increase the optimal performance time of the entire array of devices.

A method and apparatus for different embodiments of probabilistic summary data structure based encoding for garbage collection are described. In one embodiment, a method comprises generating a probabilistic summary data structure that represents active blocks of data within a storage device based on identifications of the active blocks or the data within the active blocks. The method also includes performing garbage collection of at least a portion of the storage device based on the probabilistic summary data structure.

A waste collection and disposal system for use in health care facilities is provided. The system includes a mobile waste collection unit for moving between use areas in the health care facility to collect waste material generated during medical procedures including body fluids, body tissues, saline, etc. The waste collection unit includes stacked upper and lower waste containers for receiving the waste material. During use, the upper waste container can be emptied into the lower waste container for temporary storage. In addition, different vacuum levels can be provided in the waste containers during complex procedures. Once a user desires to empty the waste collection unit, the waste collection unit is wheeled to a docking station. At the docking station, the waste material is off-loaded to a waste drain and the waste collection unit is cleaned and rinsed for further use.

A pump system for applying negative pressure to a wound, including a flow monitor capable of detecting a deviation from a reference airflow rate provided by a controlled leak to determine whether the system is operating normally or abnormally, and a flow status annunciator to indicate a normal operating condition or whether an abnormal condition is a leak or an occluded line in the system. The pump system further includes a pressure controller for regulating operation of a pump to control pressure in the system at a range around a user-selected setpoint. The pump system may also include a waste collector and a level sensor for detecting when the collector is full.

An efficient write-watch mechanism and process. A bitmap is associated with the virtual address descriptor (VAD) for a process, one bit for each virtual page address allocated to a process having write-watch enabled. As part of the write-watch mechanism, if a virtual address is trimmed to disk and that virtual address page is marked as modified, then the corresponding bit in the VAD is set for that virtual address page. In response to an API call (e.g., from a garbage collection mechanism) seeking to know which virtual addresses in a process have been modified since last checked, the memory manager walks the bitmap in the relevant VAD for the specified virtual address range for the requested process. If a bit is set, then the page corresponding to that bit is known to have been modified since last asked. If specified by the API, the bit is cleared in the VAD bitmap so that it will reflect the state since this time of asking. If the bit is not set, to determine if the page was modified, the page table entry (PTE) is checked for that page, and if the PTE indicates the page was modified, the page is known to be modified, otherwise that page is known to be unmodified since the last call. One enhancement uses page directory tables to locate a series of trimmed pages, sometimes avoiding the need to access the PTE.

A flash memory controller connected to multiple flash memory groups performs independent garbage collection operations in each group. For each group, the controller independently determines the amount of free space and performs garbage collection operations if the amount falls below a threshold.

A data storage system implements garbage collection based on the inactivity level of stored data. In one embodiment, the inactivity level of data stored in regions of a data storage system is taken into account when prioritizing regions for garbage collection. Inactivity level of memory regions can be compared to an inactivity threshold. The threshold can be adjusted during operation of the data storage system. Garbage collection can be delayed until data stored in a particular region is unlikely to be updated. Write amplification associated with garbage collection is reduced, and improved performance is attained.

Described embodiments provide a method of recovering storage space on a solid state disk (SSD). An index and valid page count are determined for each block of a segment of an SSD. If the valid page count of at least one block in the segment is zero, a quick clean is performed. A quick clean deallocates blocks having zero valid pages and places them in a queue for erasure. Otherwise, a deep clean is performed. A deep clean determines a compaction ratio, N-M, wherein N is a number of partially valid blocks and M is a number of free blocks required to compact the valid data from the N partially valid blocks into M entirely valid blocks. At least one data structure of the SSD is modified to refer to the M entirely valid blocks, and the N partially valid blocks are placed in the queue for erasure.

A non-volatile memory organized into flash erasable blocks sorts units of data according to a temperature assigned to each unit of data, where a higher temperature indicates a higher probability that the unit of data will suffer subsequent rewrites due to garbage collection operations. The units of data either come from a host write or from a relocation operation. The data are sorted either for storing into different storage portions, such as SLC and MLC, or into different operating streams, depending on their temperatures. This allows data of similar temperature to be dealt with in a manner appropriate for its temperature in order to minimize rewrites. Examples of a unit of data include a logical group and a block.

Architectural support for generation isolation is provided through trapping of intergenerational pointer stores. Identification of pointer stores as intergenerational is performed by a store barrier responsive to an intergenerational pointer store trap matrix that is programmably encoded with store target object and store pointer data generation pairs to be trapped. The write barrier and intergenerational pointer store trap matrix provide a programmably-flexible definition of generation pairs to be trapped, affording a garbage collector implementer with support for a wide variety of generational garbage collection methods, including remembered set-based methods, card-marking type methods, write barrier based copying collector methods, etc., as well as combinations thereof and combinations including train algorithm type methods to managing mature portions of a generationally collected memory space. Pointer specific store instruction replacement allows implementations in accordance with this invention to provide an exact barrier to not only pointer stores, but to the specific intergenerational pointer stores of interest to a particular garbage collection method or combination of methods.

A method and system for performing garbage collection in a memory is disclosed. Aspects of the exemplary embodiment include dividing garbage collection into atomic operations, including read, write, and block erase; storing read cycle times, write cycle times, and block erase cycle times of the memory; receiving a communication from a processor indicating at least one idle period when an application executing on the processor will not make a request of the memory, wherein the communication indicates a time duration of the at least one idle period; and in response, performing at least one of the garbage collection atomic operations within the time duration, whereby garbage collection can be performed during the at least one idle period, rather than when the memory is substantially full.

Priority-based garbage collection utilizes attributes of data stored in the non-volatile memory array in order to improve efficiency of garbage collection and of the overall data storage system. A set of low priority data can be selectively evicted from a non-volatile memory array. This can, for example, reduce write amplification associated with garbage collection. Another set of low priority data can be regrouped or consolidated in a different region of the non-volatile memory array. In addition, flushing of data can be performed in order to enhance or optimize garbage collection. Performance and endurance can thereby be improved.

A method and system for performing generational garbage collection on a virtual heap in a virtual machine is provided. The garbage collection method is suited for use with small consumer and appliance devices that have a small amount of memory and may be using flash devices as persistent storage. The garbage collection method may provide good performance where only a portion of the virtual heap may be cached in the physical heap. The virtual heap may use a single address space for both objects in the store and the in-memory heap. In one embodiment, a single garbage collector is run on the virtual heap address space. The garbage collection method may remove non-referenced objects from the virtual heap. The garbage collection method may also include a compaction phase to reduce or eliminate fragmentation, and to improve locality of objects within the virtual heap. In one embodiment, the garbage collector for the virtual heap may be implemented as a generational garbage collector using working sets in the virtual heap, where each generation is confined to a working set of the heap. The generational garbage collector may allow the flushing of changes after each garbage collection cycle for each working set region. Heap regions with different flushing policies may be used. An object nursery region without flushing where objects are initially created may be used. When a garbage collection cycle is run, objects truly referenced in the object nursery may be copied back into heap regions to be flushed, while short-lived objects no longer referenced may be deleted without flushing.

A method, article of manufacture and apparatus for automatically predicting out of memory exceptions in garbage collected environments are disclosed. One embodiment provides a method of predicting out of memory events that includes monitoring an amount of memory available from a memory pool during a plurality of garbage collection cycles. A memory usage profile may be generated on the basis of the monitored amount of memory available, and then used to predict whether an out of memory exception is likely to occur.

In a memory system with a file storage system, an optimal file handling scheme is adaptively selected from a group thereof based on the attributes of the file being handled. The file attributes may be obtained from a host or derived from a history of the file had with the memory system. In one embodiment, a scheme for allocating memory locations for a write operation is dependent on an estimated size of the file to be written. In another embodiment, a scheme for allocating memory locations for a relocation operation, such as for garbage collection or data compaction, is dependent on an estimated access frequency of the file in question. In this way, the optimal handling scheme can be used for the particular file at any time.

A method and system for garbage collecting managed and unmanaged memory that is no longer referenced. The time between allocations is compared with a threshold to determine if the garbage collector needs to collect unused memory. Unmanaged memory referenced by objects in the unused managed memory may be freed during the collection.

Measurement / analysis unit in a Java virtual machine has the function of measuring data when an event of garbage collection occurs, and the function of periodically measuring data. The measurement / analysis unit analyzes the measured data and predicts a danger of a memory shortage, and predicts a danger using an algorithm depending on the type of garbage collection used by the Java virtual machine. An application server is notified of a warning of the predicted danger of a memory shortage by an analysis result notification means by an inter-process communication, or the like. The measurement / analysis unit calculates a memory capacity required to avoid the predicted danger of a memory shortage, and the calculated memory capacity is transmitted to the application server by the analysis result notification means by an inter-process communication, or the like in the same way as the warning.

A method and an apparatus that improves virtual memory management. The proposed method and apparatus provides an application with an efficient channel for communicating information about future behavior of an application with respect to the use of memory and other resources to the OS, a paging daemon, and other system software. The state of hint bits, which are integrated into page table entries and TLB entries and are used for communicating information to the OS, can be changed explicitly with a special instruction or implicitly as a result of referencing the associated page. The latter is useful for canceling hints. The method and apparatus enables memory allocators, garbage collectors, and compilers (such as those used by the Java platform) to use a page-aligned heap and a page-aligned stack to assist the OS in effective management of memory resources. This mechanism can also be used in other system software.

The present invention is a method and system of automatic memory management (garbage collection). An application automatically marks up objects referenced from the “extended root set”. At garbage collection, the system starts traversal from the marked-up objects. It can conduct accurate garbage collection in a non-GC language, such as C++. It provides a deterministic reclamation feature. An object and its resources are released immediately when the last reference is dropped. Application codes automatically become entirely GC-safe and interruptible. A concurrent collector can be pause-less and with predictable worst-case latency of micro-second level. Memory usage is efficient and the cost of reference counting is significantly reduced.

A system for garbage collection of memory objects in a memory heap. The system includes memory heap that is partitioned into respective old and young areas. The old area is partitioned into cars and is further associated with card markings and remembered sets data structures. The card markings include for each card, a card time stamp that represents the time that the card was updated. The car includes, for each car, a car time entry stamp that represents the time the remembered set of the car was updated. The system further includes a processor communicating with the memory, and being capable of identifying all cards that were updated later than the remembered set of a selected car. In response to the event, it performs identifying change in pointers that refer from the card to a memory object in the selected car and in response to identified change in pointers, updating the remembered set of the car with the identified pointers. The process is further capable of updating the car time stamp of the selected car.

A processor of a management computer acquires the free disk space amount of a disk pool, acquires the invalid disk space amount from a plurality of host computers, determines a host computer to which the instruction for the physical disk space collection is issued on the basis of the invalid disk space amount, and judges that the free disk space amount is smaller than a predetermined threshold value before transmitting a GC control request to the determined host computer; another processor generates and transmits invalid disk space position information indicating the position of the invalid disk space in a virtual volume in cases where a host investigation request is received; and the other processor collects the physical disk space of a physical disk allocated to the storage disk space of the virtual volume in the disk pool.

A non-volatile memory organized into flash erasable blocks sorts units of data according to a temperature assigned to each unit of data, where a higher temperature indicates a higher probability that the unit of data will suffer subsequent rewrites due to garbage collection operations. The units of data either come from a host write or from a relocation operation. Among the units more likely to suffer subsequent rewrites, a smaller subset of data super-hot is determined. These super-hot data are then maintained in a dedicated portion of the memory, such as a resident binary zone in a memory system with both binary and MLC portions.