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: 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: 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: 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: Methods and systems are disclosed for backup using a metadata virtual hard drive (VHD) and a differential VHD. A particular system includes a memory device that stores files and a backup agent configured to detect changes to the files. The system includes a translation module configured to translate the detected changes into VHD formatted changes and a VHD module configured to write the VHD formatted changes to a metadata VHD stored at the memory device. The VHD module is also configured to generate a differential VHD based on the metadata VHD. A network interface at the system is configured to transmit the metadata VHD and the differential VHD to a remote storage device.

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: Systems and methods are described that facilitate management of file system filters, comprising a filter manager that maps altitudes of minifilters to legacy filter order groups. An aspect of the present invention provides for minifilters that can dynamically load and unload, thus facilitating increased flexibility in filter system management.

Abstract: A generic disk driver filter may be used to accelerate performance when writing to a disk. The generic disk driver filter may be connected between a file system and a disk driver and may be configured to be extensible and compatible with a variety of different file systems and different disk drivers. The generic disk driver filter has a filter component that intercepts and filters raw sector write commands from the file system before they are received by the disk driver. The generic disk driver filter may also have a cache memory component that stores a checksum for each sector which is written to the disk. The generic disk driver filter may also have a scavenger thread component that detects and removes latent checksum entries from the cache memory so as to preserve memory availability and reduce memory requirements.

Abstract: Aspects of the subject matter described herein relate to distributed namespace aggregation. In aspects, a distributed file system is extended to allow multiple servers to seamlessly host files associated with aggregated links and/or aggregated roots. A request for a directory listing of an aggregated link or root may cause a server to sniff multiple other servers that host files associated with the link or root to create and return a concatenated result. Sniffing may also be used to determine which servers host the file to which the client is requesting access. Altitude may be used to determine which servers to make visible to the client and may also be used to determine which servers are in the same replica group and which are not.

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 system and method for organizing and sorting targets received in a referral response and for realizing a target fail-back and a target priority policy in a distributed file system is provided. In one embodiment, a sorting method includes receiving a referral response in the form of a list of targets that are sorted into bounded sets. Having a sorted referral response in bounded sets provides a basis for implementing a target fail-back and a target priority policy. The computer system may select a target from a sorted list of targets sorted according to site-cost and/or target priority. Then, the computer system may determine if the set target is associated with a more preferred target when compared to all available targets in the sorted list and if not, switch back to a more preferred target.

Abstract: A method and system for limiting resource usage of a version store. A limit indicates a total amount of resources that may be consumed by in-progress transactions. A running total of the amount of remaining resources is maintained. Before a new transaction is started, a determination is made as to whether there are enough resources remaining to complete the new transaction. If so, the transaction starts and the running total is adjusted. If not, the transaction waits until more resources are available. When a transaction completes, if it is the oldest in-progress transaction, resources are released. Otherwise, the resources associated with the transaction are not released until all transactions that started before the transaction have completed. This ensures that a client of a version store does not exceed the limit of resources that may be consumed by in-progress transactions.

Abstract: File system methods and systems enabling efficient detection that a filename exists, by executing a hash function on the file name to reduce the overall computational complexity of determining that a directory entry might match the target filename, prior to performing the string comparison to determine the entry does match the target filename. A cross-device extensible means of providing a conversion function, such as uppercasing the filename, occurs prior to the hash. Methods of creating, deleting, and modifying the directory entries is further provided, as well as details of an embodiment of the file system described.

Abstract: Disclosed is a method for creating and reading a contiguous file in an extensible file system. During the creation of a file on the storage media, the file system format check the bitmap to determine if there are areas of free space on the media that would permit the storage of the file in a contiguous manner. By storing the file in a contiguous manner the file may later be read without resorting to the file allocation table, because the file itself would not be fragmented on the storage media. Once an area of free space has been identified, the file is written to the media in a contiguous manner. Further, an associated entry for the file in the directory entry is updated or created to indicate that the file is a contiguous file and also provides basic parameters necessary to read the file without resorting to accessing the file allocation table.

Abstract: Described is maintaining cached hash values for files in association with state data for each file that represents the state of that file's contents at the time of hashing. For example, in a journaling file system, the state data may comprise the update sequence number of the file in the journal and a journal identifier for that journal instance. A request for a hash value for a file is processed by determining whether a cached hash value is maintained for that file. If so, and the associated maintained state data matches current state data for the file, the file contents are unchanged since the last hash computation, whereby the cached hash value is returned in response to the request. Otherwise, a new hash value is computed for the file and returned, and cached for future use. Multiple types of hashes may be cached for a given file.

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: 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: Described is a technology by which a new volume or partition may be created on a disk, e.g., by running a shrink program and then reclaiming freed space. Shrink occurs online, while the user or system processes may be otherwise using the disk for reads and writes. Further, the technology operates while protecting snapshot versions of the volume. To shrink, upon receiving a request to shrink a volume to within a boundary, new allocations are restricted such that any allocation is to a volume area within the boundary. Data is moved from outside the boundary to within the boundary, and the shrink is committed when no volume data remains outside the boundary. A reduced-size volume or partition that does not include the specified region is committed when the data has been moved out of the specified region. A new volume or partition may be freed that corresponds to the region.

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 system, a method, and program products for buffering data from a file in a hierarchical data storage system allocates data buffers and buffer management structures in memory to optimize performance of no recall requests. Buffer management structures, such as buffer headers and hash queue headers, are used to optimize performance of insert, search, and data buffer reuse operations. Buffer headers are managed in a least-recently-used queue in accordance with a relative availability status. Buffer headers are also organized in hash queue structures in accordance with file-based identifiers to facilitate searching for requested data in the buffers. Data buffers can be used to buffer different data blocks within the same file and can be recycled to buffer data from other data blocks and other files from the secondary storage device. Data in a data block may be reread by the requesting process or by other processes as long as the requested data remains valid.