Abstract: A popular service offered by many cloud computing systems is cloud-based storage. To enhance this service, the cloud-based storage can be extended through the use of a local storage device. A local storage device, such as a network enabled external hard drive, can be made available via a user's Internet connection. The local storage device can then be used to transparently store the user's content. That is, the user can still back up their devices to the cloud, but in some cases instead of the content residing in the cloud-based storage, it can reside on the local storage device without additional action required by the user. When the user requests the content, the content can be retrieved from the local storage device and returned to the requesting client device without the client device knowing where the content was stored.

Abstract: A cloud computing system can be used to facilitate data item sharing and collaboration among groups of users through the creation and management of collections. A group of users, each of which is associated with at least one client device, can subscribe to a collection. A subscribed user can create a data item locally on a client device and assign the data item to a collection. In response to the assignment, each user subscribed to the collection can receive and store a copy of the data item locally on a client device. Any modifications made to a local copy of the data item can automatically be distributed to each subscribed user's client device. The modifications, including conflicting modifications, can be merged into the local copy.

Abstract: A composite memory device that includes different types of non-volatile memory devices, which have different performance characteristics, is described. This composite memory device may receive requests, a given one of which includes a command, a logical address for at least a block of data associated with the command, and a hint associated with the command. For the given request, the composite memory device executes the command on the block of data at the logical address in at least one of the types of non-volatile memory devices. Furthermore, the composite memory device conditionally executes the hint based on one or more criteria, such as: available memory in the types of non-volatile memory devices, traffic through an interface circuit in the composite memory device, operational states of the types of non-volatile memory devices, a target performance characteristic of the composite memory device, and an environmental condition of the composite memory device.

Abstract: Methods, systems, and apparatus, including computer programs encoded on a computer storage medium, for data storage. In one aspect, a method includes the actions of identifying a running query from an application; determining one or more data items of a plurality of data items that the application has permission to view according to one or more application specific access policies; and presenting the one or more data items to the application while not presenting other data items of the plurality of data items.

Abstract: In one aspect, an embodiment of file system error detection and protection includes collecting first data identifying at least one error in performing at least one of reading or writing data to a storage device and determining, through an association between the first data and file identifiers, a set of files which are effected by the at least one error. The collecting may be performed automatically as a background process. In another aspect, an embodiment includes detecting at least one error in file system metadata for a storage device, the detecting being performed automatically as a background process, and storing state information automatically in response to the detecting; the state information indicates that upon next mounting of the storage device, the data processing system will automatically cause the running of a file system check of the file system metadata.

Abstract: Methods, systems, and apparatus, including computer programs encoded on a computer storage medium, for file system management. In one aspect, a method includes receiving a request at a kernel to perform a file operation on a particular file; identifying a flag bit associated with the file; invoking user space file handler to perform particular action when the flag bit is set; determining whether notification that action has been performed by file handler is received; and allowing the file operation on the file when notification is received.

Abstract: Methods, systems, and apparatus, including computer programs encoded on a computer storage medium, for data synchronization. In general, one aspect of the subject matter described in this specification can be embodied in methods that include the actions of receiving a knowledge vector from a first device of the pair of devices, the knowledge vector identifying data items and latest changes to the data items known to the peer device; comparing, at a second device of the pair of devices, the received knowledge vector with a local knowledge vector for changes unknown to the first device; and sending a list of changes to the first device.

Abstract: Methods, systems, and apparatus, including computer programs encoded on a computer storage medium, for storing data. In one aspect, a method includes receiving a user input to present a visual representation of a first prior state of a file system; generating the first visual representation of a first prior state of the file system at a first time in the past according to a first virtual file system corresponding to that first time; presenting the first visual representation, where the first virtual file system is a reduced representation of the file system at that first time; receiving a user input to present a second visual representation of a second prior state of the file system at a second time in the past according to a second virtual file system corresponding to that second time; and presenting the second visual representation.

Abstract: Methods, systems, and apparatus, including computer programs encoded on a computer storage medium, for storing data. In one aspect, a method includes detecting at a kernel a plurality of operations, each of a particular type from a plurality of types, to be performed on a respective data item; and generating respective entries in a delta store in response to the detected plurality of operations wherein each entry for a data item includes a marker attribute corresponding to the operation type of the plurality of types.

Abstract: Methods, systems and machine readable media for file system error detection and protection are described. In one aspect, an embodiment of a method includes collecting first data identifying at least one error in performing at least one of reading or writing data to a storage device and determining, through an association between the first data and file identifiers, a set of files which are effected by the at least one error. The collecting may be performed automatically as a background process. In another aspect, an embodiment of a method includes detecting at least one error in file system metadata for a storage device, the detecting being performed automatically as a background process, and storing state information automatically in response to the detecting; the state information indicates that upon next mounting of the storage device, the data processing system will automatically cause the running of a file system check of the file system metadata.