Abstract: A versioned file system comprises a set of structured data representations, such as XML. Each structured data representation corresponds to a “version,” and each version comprises a tree of write-once objects rooted at a root directory manifest. Each version in the versioned file system has associated therewith a “borrow window.” When it is desired to reconstruct the file system to a point in time (or, more generally, a given state), i.e., to perform a “restore,” it is only required to walk (use) a single structured data representation (a tree). During a restore, metadata is pulled back from the cloud first, so users can see the existence of needed files immediately. The remainder of the data is then pulled back from the cloud if/when the user goes to open the file. As a result, the entire file system (or any portion thereof) can be restored to a previous time nearly instantaneously.

Abstract: An archive cluster application runs in a distributed manner across a redundant array of independent nodes. Each node preferably runs a complete archive cluster application instance. A given nodes provides a data repository, which stores up to a large amount (e.g., a terabyte) of data, while also acting as a portal that enables access to archive files. Each symmetric node has a set of software processes, e.g., a request manager, a storage manager, a metadata manager, and a policy manager. The request manager manages requests to the node for data (i.e., file data), the storage manager manages data read/write functions from a disk associated with the node, and the metadata manager facilitates metadata transactions and recovery across the distributed database. The policy manager implements one or more policies, which are operations that determine the behavior of an “archive object” within the cluster. The archive cluster application provides object-based storage.

Abstract: An archive cluster application runs in a distributed manner across a redundant array of independent nodes. Each node preferably runs a complete archive cluster application instance. A given nodes provides a data repository, which stores up to a large amount (e.g., a terabyte) of data, while also acting as a portal that enables access to archive files. Each symmetric node has a set of software processes, e.g., a request manager, a storage manager, a metadata manager, and a policy manager. The request manager manages requests to the node for data (i.e., file data), the storage manager manages data read/write functions from a disk associated with the node, and the metadata manager facilitates metadata transactions and recovery across the distributed database. The policy manager implements one or more policies, which are operations that determine the behavior of an “archive object” within the cluster. The archive cluster application provides object-based storage.

Abstract: An archival storage cluster of preferably symmetric nodes includes a data privacy scheme that implements key management through secret sharing. In one embodiment, the protection scheme is implemented at install time. At install, an encryption key is generated, split, and the constituent pieces written to respective archive nodes. The key is not written to a drive to ensure that it cannot be stolen or otherwise compromised. Due to the secret sharing scheme, any t of the n nodes must be present before the cluster can mount the drives. Thus, to un-share the secret, a process runs before the cluster comes up. It contacts as many nodes as possible to attempt to reach a sufficient t value. Once it does, the process un-shares the secret and mounts the drives locally. Given bidirectional communication, this mount occurs more or less at the same time on all t nodes. Once the drives are mounted, the cluster can continue to boot as normal.

Abstract: A client player performs a query to a nameserver against a network map of Internet traffic conditions. The query is made asking for a particular service (e.g., RTSP) via a particular protocol (TCP) in a particular domain. In response, the nameserver returns a set of one or more tokens, with each token defining a machine or, in the preferred embodiment, a group of machines, from which the player should seek to obtain the stream. The player may then optionally perform one or more tests to determine which of a set of servers provides a best quality of service for the stream. That server is then used to retrieve the stream. Periodically, the client player code repeats the query during stream playback to determine whether there is a better source for the stream. If a better source exists, the player performs a switch to the better stream source “on the fly” if appropriate to maintain and/or enhance the quality of service.

Abstract: A client player performs a query to a nameserver against a network map of Internet traffic conditions. The query is made asking for a particular service (e.g., RTSP) via a particular protocol (TCP) in a particular domain. In response, the nameserver returns a set of one or more tokens, with each token defining a machine or, in the preferred embodiment, a group of machines, from which the player should seek to obtain the stream. The player may then optionally perform one or more tests to determine which of a set of servers provides a best quality of service for the stream. That server is then used to retrieve the stream. Periodically, the client player code repeats the query during stream playback to determine whether there is a better source for the stream. If a better source exists, the player performs a switch to the better stream source “on the fly” if appropriate to maintain and/or enhance the quality of service.

Abstract: An archive cluster application runs in a distributed manner across a redundant array of independent nodes. Each node preferably runs a complete archive cluster application instance. A given nodes provides a data repository, which stores up to a large amount (e.g., a terabyte) of data, while also acting as a portal that enables access to archive files. Each symmetric node has a set of software processes, e.g., a request manager, a storage manager, a metadata manager, and a policy manager. The request manager manages requests to the node for data (i.e., file data), the storage manager manages data read/write functions from a disk associated with the node, and the metadata manager facilitates metadata transactions and recovery across the distributed database. The policy manager implements one or more policies, which are operations that determine the behavior of an “archive object” within the cluster. The archive cluster application provides object-based storage.

Abstract: A reflector network is used within a content delivery network to enable requesting end users to subscribe to live streams that have been published to CDN entry points. A reflector is a generalized packet router program. The reflector network preferably comprises a hierarchy of reflectors that are located at the various entry points into the CDN, at each edge node at which requesting users may be directed by the CDN to obtain live streams, and at various “reflector” nodes located within at least one intermediate layer (in the hierarchy) between the entry points and the edge nodes. The edge nodes and each reflector node also include a manager program that arranges for feeds. When an end user is directed to an edge node that is not yet receiving the desired stream, the edge node's manager issues a subscription request to a set of reflector nodes. If the reflector node(s) are already receiving the desired stream, their reflector(s) begin sending it to the requesting edge node.

Abstract: An enterprise content delivery network includes two basic components: a set of content servers, and a central controller for providing coordination and control of the content servers. The central controller coordinates the set of distributed servers into a unified system, for example, by providing provisioning, content control, request mapping, monitoring and reporting. Content requests may be mapped to optimal content servers by DNS-based mapping, or by using a policy engine that takes into consideration such factors as the location of a requesting client machine, the content being requested, asynchronous data from periodic measurements of an enterprise network and state of the streaming media servers, and given capacity reservations on the enterprise links. An ECDN provisioned with the basic components facilitates various customer applications, such as one or more of the following: live, corporate, streaming media (internal and Internet sources) and HTTP content delivery.

Abstract: A reflector network is used within a content delivery network to enable requesting end users to subscribe to live streams that have been published to CDN entry points. A reflector is a generalized packet router program. The reflector network preferably comprises a hierarchy of reflectors that are located at the various entry points into the CDN, at each edge node at which requesting users may be directed by the CDN to obtain live streams, and at various “reflector” nodes located within at least one intermediate layer (in the hierarchy) between the entry points and the edge nodes. The edge nodes and each reflector node also include a manager program that arranges for feeds. When an end user is directed to an edge node that is not yet receiving the desired stream, the edge node's manager issues a subscription request to a set of reflector nodes. If the reflector node(s) are already receiving the desired stream, their reflector(s) begin sending it to the requesting edge node.

Abstract: A drill/driver (eg. an electric drill) with a screwdriver attachment, and a method of controlling the drill/driver, are described. A control circuit (30) controls the speed of rotation of the motor (38, 39) through a time delay circuit (42) and a triac (41). The control circuit (30) uses the time delay information and information inputted from a rotational speed sensor (43) to monitor the current in the motor or a parameter related at least in part to current in the motor. When a change corresponding to an increase in the rate of change of current in the motor is detected, the control circuit (30) stops the motor to provide an automatic torque control feature for a screwdriving operation.

Abstract: A multi-function hand-held power tool includes an electric motor for driving a tool holder and control means for energizing the motor in accordance with a selected combination of operating conditions under which the tool is to be used. Located on the housing of the tool is a keyboard for inputting to the control means information to define the selected combinations of conditions. The keyboard has a first single key for selecting a tool function, for example drilling, from a defined range of tool functions, a second single key from selecting a required workpiece material for example wood, from a defined range of workpiece materials, and two further keys for selecting, from a defined range, another parameter, for example drill size, appropriate to the selected tool function. A visual display also located on the tool housing is energizable to show symbols indicative of the selected combination of operating conditions.