Abstract: Securely performing file operations. A method includes determining a trust characteristic assigned to a file. When the trust characteristic assigned to the file meets or exceeds a predetermined trust condition, then the method includes performing a file operation on the file in a host operating system while preventing the file operation from being performed in the container operating system. When the trust characteristic assigned to the file does not meet or exceed the predetermined trust condition, then the method includes performing the file operation on the file in the container operating system while preventing the file operation from being performed directly in the host operating system.

Abstract: Native file encryption support is integrated into an existing file system that does not provide such support, such as the FAT family of file systems, while maintaining backwards compatibility with previous implementations of these file systems.

Abstract: Systems and methods for detecting legacy storage devices that may falsely and/or incorrectly report to host systems that they have removable media. Such false or incorrect reporting may cause the host system to periodically poll the storage device as to whether the device is ready for I/O processing. Such polling would be unnecessary and represent a waste of power expended by the host system. In one embodiment, the present system may implement processes that periodically poll storage media and update a database. The database would be a listing of storage devices indicating whether they truly have removable media or falsely report that they have removable media. In another embodiment, the present system may apply some heuristically testing to determine whether a storage device so falsely indicates removable media. In another embodiment, telemetry service may be used by a group of hosts to share data regarding such storage devices.

Abstract: Securely performing file operations. A method includes determining a trust characteristic assigned to a file. When the trust characteristic assigned to the file meets or exceeds a predetermined trust condition, then the method includes performing a file operation on the file in a host operating system while preventing the file operation from being performed in the container operating system. When the trust characteristic assigned to the file does not meet or exceed the predetermined trust condition, then the method includes performing the file operation on the file in the container operating system while preventing the file operation from being performed directly in the host operating system.

Abstract: Native file encryption support is integrated into an existing file system that does not provide such support, such as the FAT family of file systems, while maintaining backwards compatibility with previous implementations of these file systems.

Abstract: Native file encryption support is integrated into an existing file system that does not provide such support, such as the FAT family of file systems, while maintaining backwards compatibility with previous implementations of these file systems.

Abstract: Systems and methods for detecting legacy storage devices that may falsely and/or incorrectly report to host systems that they have removable media. Such false or incorrect reporting may cause the host system to periodically poll the storage device as to whether the device is ready for I/O processing. Such polling would be unnecessary and represent a waste of power expended by the host system. In one embodiment, the present system may implement processes that periodically poll storage media and update a database. The database would be a listing of storage devices indicating whether they truly have removable media or falsely report that they have removable media. In another embodiment, the present system may apply some heuristically testing to determine whether a storage device so falsely indicates removable media. In another embodiment, telemetry service may be used by a group of hosts to share data regarding such storage devices.

Abstract: Systems and methods for detecting legacy storage devices that may falsely and/or incorrectly report to host systems that they have removable media. Such false or incorrect reporting may cause the host system to periodically poll the storage device as to whether the device is ready for I/O processing. Such polling would be unnecessary and represent a waste of power expended by the host system. In one embodiment, the present system may implement processes that periodically poll storage media and update a database. The database would be a listing of storage devices indicating whether they truly have removable media or falsely report that they have removable media. In another embodiment, the present system may apply some heuristically testing to determine whether a storage device so falsely indicates removable media. In another embodiment, telemetry service may be used by a group of hosts to share data regarding such storage devices.

Abstract: Native file encryption support is integrated into an existing file system that does not provide such support, such as the FAT family of file systems, while maintaining backwards compatibility with previous implementations of these file systems.

Abstract: Systems and methods for detecting legacy storage devices that may falsely and/or incorrectly report to host systems that they have removable media. Such false or incorrect reporting may cause the host system to periodically poll the storage device as to whether the device is ready for I/O processing. Such polling would be unnecessary and represent a waste of power expended by the host system. In one embodiment, the present system may implement processes that periodically poll storage media and update a database. The database would be a listing of storage devices indicating whether they truly have removable media or falsely report that they have removable media. In another embodiment, the present system may apply some heuristically testing to determine whether a storage device so falsely indicates removable media. In another embodiment, telemetry service may be used by a group of hosts to share data regarding such storage devices.

Abstract: A model in which filter drivers are managed to receive callbacks for I/O requests in which the filter drivers have registered an interest. Per-volume instances of filter drivers register with a filter manager for pre-callbacks (for I/O to the file system) and post-callbacks (for I/O from the file system), and identify which I/O requests (e.g., create, read, write) they are registering to receive callbacks. The filter manager orders the instances for callbacks. When an I/O request is received, the filter manager converts the I/O request to callback data and calls the interested filters in the callback order, whereby the filter instances can process the I/O data. As the request returns from the file system, filters desiring post callbacks are called in the reverse order. Efficient context management for the filters and other functions, such as non-reentrant file I/O, are also provided by the model.

Abstract: An extensible file system format for portable storage media is provided. The extensible file system format includes the specification of primary and secondary directory entry types that may be custom defined. The primary and secondary directory entry types can be further classified as critical and benign directory entries. The directory entry types can define whether a cluster chain corresponding to a file can be contiguously allocated.

Abstract: A file system which is enabled to use a Metadata Partition instead of VAT for write-once discs, is provided by a pseudo-overwrite method. On applying this invention to a drive apparatus which supports pseudo-overwrite media, the file system distinguishes data to overwrite from data to append. When the data is newly written to a logical sector (S1305), the drive apparatus writes the data to a physical sector to which the logical sector corresponds (S1311). When the logical sector is overwritten the data is written to another unrecorded physical sector in the volume space (1321), and remapping information that specifies the original address, and the remapping address are stored in the remapping table (S1322).

Abstract: Aspects of the subject matter described herein relate to file system filters and transactions. In aspects, a filter may enlist to receive notification of events associated with a transaction. Afterwards, the filter may receive notification of a transaction event for which it has enlisted. In response to receiving notification of the transaction the filter may perform an action as appropriate. Aspects of the subject matter described herein may be applied to stacked and managed filters.

Abstract: File system metadata regarding states of a file system affected by transactions is tracked consistently even in the face of dirty shutdowns which might cause rollbacks in transactions which have already been reflected in the metadata. In order to only request time- and resource-heavy rebuilding of metadata for metadata which may have been affected by rollbacks, reliability information is tracked regarding metadata items. When a metadata item is affected by a transaction which may not complete properly in the case of a problematic shutdown or other event, that metadata item's reliability information indicates that it may not be reliable in case of such a problematic (“dirty” or“abnormal”) event. In addition to flag information indicating unreliability, timestamp information tracking a time of the command which has made a metadata item unreliable is also maintained.

Abstract: A model in which filter drivers are managed to receive callbacks for I/O requests in which the filter drivers have registered an interest. Per-volume instances of filter drivers register with a filter manager for pre-callbacks (for I/O to the file system) and post-callbacks (for I/O from the file system), and identify which I/O requests (e.g., create, read, write) they are registering to receive callbacks. The filter manager orders the instances for callbacks. When an I/O request is received, the filter manager converts the I/O request to callback data and calls the interested filters in the callback order, whereby the filter instances can process the I/O data. As the request returns from the file system, filters desiring post callbacks are called in the reverse order. Efficient context management for the filters and other functions, such as non-reentrant file I/O, are also provided by the model.

Abstract: An extensible file system format for portable storage media is provided. The extensible file system format includes the specification of primary and secondary directory entry types that may be custom defined. The primary and secondary directory entry types can be further classified as critical and benign directory entries.

Abstract: A method and system for caching remote objects locally. A request to access an object is received. A determination is made as to whether the object is cached. If the object is cached and the request is not to create a new object, modify an existing object, or open a directory, the request is directed to a local file system. Otherwise, the request is directed to a remote file system. Information about which objects are requested may be used to copy objects stored remotely to a local server as specified by a caching policy.

Abstract: A method and system for updating a filter's data after the filter's metadata file is restored. The filter maintains an open handle to the metadata until the filter receives a request to have the metadata restored. The filter then closes the open handle and allows the metadata to be restored. After the metadata is restored, data associated with the filter is rebuilt based on the restored metadata.

Abstract: A method and system for computing disk space used by a directory and its descendants that may proceed while input and output are occurring that involve the directory and any of its descendants. A calculation of the total amount of disk space consumed by a set of objects is commenced. While performing the calculation, changes to the objects are monitored. If a change to one or more of the objects affects the disk space consumed by the objects, the calculation is changed so that the total reflects the change to the one or more objects.