Abstract: A backscatter tag communicate device includes, in part, a receiver configured to receive a WiFi packet conforming to a communication protocol defining a multitude of codewords, a mapper configured to map at least a first subset of the multitude of codewords disposed in the packet to a second multitude of codewords defined by the protocol, and a frequency shifter configured to shift a frequency of the second multitude of codewords such that the frequency shifted codewords are characterized by a single sideband spectrum. The communication protocol may be the 802.11b communication protocol. The mapper may optionally map the first subset of the multitude of codewords by changing phases of the first subset of the multitude of codewords.

Abstract: Techniques for implementing data deduplication in conjunction with thick and thin provisioning of storage objects are provided. In one embodiment, a system can receive a write request directed to a storage object stored by the system and can determine whether the storage object is a thin or thick object. If the storage object is a thin object, the system can calculate a usage value by adding a total amount of physical storage space used in the system to a total amount of storage space reserved for thick storage objects in the system and further subtracting a total amount of reserved storage space for the thick storage objects that are filled with unique data. The system can then reject the write request if the usage value is not less than the total storage capacity of the system.

Abstract: In accordance with the present disclosure, files may be deduplicated in a distributed storage system having a plurality of storage volumes. A uniqueness metric for each file may indicate a degree of deduplication of the respective data files in the given storage volume. The uniqueness metric may be used to identify files for rebalancing in the distributed storage system. The uniqueness metric may be efficiently calculated with enough accuracy using a sampling methodology.

Abstract: Techniques for implementing data deduplication in conjunction with thick and thin provisioning of storage objects are provided. In one embodiment, a system can receive a write request directed to a storage object stored by the system and can determine whether the storage object is a thin or thick object. If the storage object is a thin object, the system can calculate a usage value by adding a total amount of physical storage space used in the system to a total amount of storage space reserved for thick storage objects in the system and further subtracting a total amount of reserved storage space for the thick storage objects that are filled with unique data. The system can then reject the write request if the usage value is not less than the total storage capacity of the system.

Abstract: Techniques for a motion tracing device using radio frequency signals are presented. The motion tracing device utilizes radio frequency signals, such as WiFi to identify moving objects and trace their motion. Methods and apparatus are defined that can measure multiple WiFi backscatter signals and identify the backscatter signals that correspond to moving objects. In addition, motion of a plurality of moving objects can be detected and traced for a predefined duration of time.

Abstract: Exemplary methods, apparatuses, and systems include a first layer of a virtual storage area network (VSAN) module receiving a write request from a data compute node. The write request includes data to be written and the VSAN module is distributed across a plurality of computers to provide an aggregate object store using storage attached to each of the plurality of computers. The first layer of the VSAN module calculates a checksum for the data to be written and passes the data to be written and the checksum to a second layer of the VSAN module. The second layer of the VSAN module calculates a first verification checksum for the data to be written. The data and the checksum are written to persistent storage in response to determining the first verification checksum matches the checksum passed by the first layer of the VSAN module.

Abstract: Free storage blocks previously allocated to a logical block device are released back to an underlying storage system supporting the logical block device in a manner that does not conflict with write operations that may be issued to the free storage blocks at about the same time. According to a first technique, write operations on the same storage blocks to be released are paused until the underlying storage system has completed the releasing operation or, if the write operations are issued earlier than when the underlying storage system actually performs the releasing operation, such storage blocks are not released. According to a second technique, a special file is allocated the free storage blocks, which are then made available for safe releasing.

Abstract: Techniques for estimating one or more backscatter signals reflected from one or more objects are disclosed. In one example, a backscatter sensor includes, in part, a receiver for receiving a composite signal comprising one or more reflections of a transmitted signal, each reflection being reflected by one of a plurality of objects; and a processor configured to estimate at least a first backscatter component of the composite signal using a progressive interference cancellation technique. The first backscatter component of the composite signal corresponds to a reflection of the transmitted signal from a first object. In one embodiment, the backscatter sensor includes multiple receivers and/or one or more transmitters.

Abstract: Free storage blocks previously allocated to a logical block device are released back to an underlying storage system supporting the logical block device in a manner that does not conflict with write operations that may be issued to the free storage blocks at about the same time. According to a first technique, write operations on the same storage blocks to be released are paused until the underlying storage system has completed the releasing operation or, if the write operations are issued earlier than when the underlying storage system actually performs the releasing operation, such storage blocks are not released. According to a second technique, a special file is allocated the free storage blocks, which are then made available for safe releasing.

Abstract: Free storage blocks previously allocated to a logical block device are released back to an underlying storage system supporting the logical block device in a manner that does not conflict with write operations that may be issued to the free storage blocks at about the same time. According to a first technique, write operations on the same storage blocks to be released are paused until the underlying storage system has completed the releasing operation or, if the write operations are issued earlier than when the underlying storage system actually performs the releasing operation, such storage blocks are not released. According to a second technique, a special file is allocated the free storage blocks, which are then made available for safe releasing.

Abstract: Devices, systems, methods, and other embodiments associated with generating a moving average are described. In one embodiment, a method includes inputting a new data value, wherein the new data value is a most recent data value in a series of M prior sequential data values that are input to an accumulator for the purpose of calculating a moving average having a window size of M. The method also includes detecting an error in the new data value and correcting the moving average, based at least in part, on the error.

Abstract: A method enables a central management service to operate on individual files within virtual disks associated with different virtual machines (VMs) running in one or more host computers that are each networked to a remote storage system. An IO request from a VM is received at a virtualization software layer on a host computer, wherein the IO request relates to a file stored in a virtual disk associated with the VM, and the file is individually stored in the remote storage system in accordance with a file system. The central management service is notified of the received IO request and uses the file system to access the file in the remote storage system to perform a management task on the file, and the IO request is then performed on the file by the virtualization software layer upon a notification of a successful completion of the management task.

Abstract: Embodiments of the disclosure provide techniques managing a log-structured solid state drive (SSD) format in a distributed storage system. SSDs in the distributed storage system maintains a journal of logical changes to storage objects to persist prepared and committed changes in the latency path. The journal includes metadata entries that describe changes and reference data pages. Dense data structures (such as a logical block addressing table) index the metadata entries. To reduce the amount of overhead in I/O operations, the distributed storage system maintains the dense data structures in memory rather than on disk.

Abstract: One embodiment of the present invention is a method for a virtual machine to access data from a virtual device, the method including: (a) attaching the virtual device to the virtual machine with a backing store that is a virtual image of a file system conforming to a predetermined file system format, wherein: (i) file system data is stored in one or more files, (ii) the virtual image includes metadata stored apart from the file system data, which metadata corresponds to the predetermined file system format, (iii) the metadata includes one or more directory records, and (iv) the one or more directory records include information that points directly or indirectly to the file system data; (b) issuing a read request for a block of data from the file system as if stored in the predetermined file system format; (c) accessing the metadata and determining the location of the requested block of data in the file system data; and (d) retrieving the requested block of data from the file system data.

Abstract: Devices, systems, methods, and other embodiments associated with generating a moving average are described. In one embodiment, a method calculates, using at least an accumulator, an average value of M sequential data values is calculated, where M is an integer. The M sequential data values are delayed before passing a delay output. The method detects a data value with an error in the M sequential data values that are delayed and controls the accumulator to correct the average value of the M sequential data values as a function of the error.

Abstract: A non-fighting fully clocked scan latch is described that is dynamically configurable to support both logic data latching and scan data latching. The described scan latch circuit design reduces a load placed on a logic data latch portion of the described circuit by a scan latch portion of the described circuit, and thereby increases the speed of the described scan latch to that of an output latch without scan capability. Power required to drive the described scan latch is reduced by clocking the circuit to avoid fighting and by reducing the number of transistors included in transistor stacks internal to the scan latch. By reducing drive power requirements, eliminating internal latch fighting, and increasing latch response, a versatile scan latch is achieved that may be successfully implemented in a wide range of circuits despite the use of different supply drive voltage, threshold voltage, source-to-drain voltage, and transistor technology combinations.

Abstract: Virtual machines are managed in centralized manner. Files that are shared by multiple virtual machines are stored in a central storage unit and a management program is executed on one or more of these files on a per file basis. The management program is executed on a file if an IO operation is issued for that file. A namespace map is used to provide a mapping of filenames used by the different virtual machines to filenames used by the central storage unit.

Abstract: Devices, systems, methods, and other embodiments associated with generating a moving average are described. In one example method an average value of a sliding window of M sequential data values is calculated on a per clock basis, where M is an integer. A data value is detected that has an error. The data value is in the sliding window of M sequential data values. The method corrects the average value of the sliding window as a function of the error.

Abstract: Free storage blocks previously allocated to a logical block device are released back to an underlying storage system supporting the logical block device in a manner that does not conflict with write operations that may be issued to the free storage blocks at about the same time. According to a first technique, write operations on the same storage blocks to be released are paused until the underlying storage system has completed the releasing operation or, if the write operations are issued earlier than when the underlying storage system actually performs the releasing operation, such storage blocks are not released. According to a second technique, a special file is allocated the free storage blocks, which are then made available for safe releasing.

Abstract: A non-fighting fully clocked scan latch is described that is dynamically configurable to support both logic data latching and scan data latching. The described scan latch circuit design reduces a load placed on a logic data latch portion of the described circuit by a scan latch portion of the described circuit, and thereby increases the speed of the described scan latch to that of an output latch without scan capability. Power required to drive the described scan latch is reduced by clocking the circuit to avoid fighting and by reducing the number of transistors included in transistor stacks internal to the scan latch. By reducing drive power requirements, eliminating internal latch fighting, and increasing latch response, a versatile scan latch is achieved that may be successfully implemented in a wide range of circuits despite the use of different supply drive voltage, threshold voltage, source-to-drain voltage, and transistor technology combinations.