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: A method of updating a file record on at least one of a first one or more computer readable storage media including writing at least three contiguous DirectoryEntry data structures corresponding to a directory entry set, the directory entry set corresponding to a file, the writing occurring to the at least one of a first one or more computer readable storage media.

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: 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: 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: 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.

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: 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. 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: 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: 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: 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: 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.