1.1 Glossary
This document uses the following terms:
access control list (ACL): A list of access control entries (ACEs) that collectively describe the security rules for authorizing access to some resource; for example, an object or set of objects.
alternate stream: See named stream.
ASCII: The American Standard Code for Information Interchange (ASCII) is an 8-bit character-encoding scheme based on the English alphabet. ASCII codes represent text in computers, communications equipment, and other devices that work with text. ASCII refers to a single 8-bit ASCII character or an array of 8-bit ASCII characters with the high bit of each character set to zero.
backup stream: The components of a Windows NT operating system backup file. It is important not to confuse a backup stream with a named stream. Backup streams are bytes within the main stream of a Windows NT backup file, while a named stream is part of a file that is not a Windows NT backup file that requires a separate open call to access.
FAT file system: A file system used to organize and manage files. The file allocation table (FAT) is a data structure that the operating system creates when a volume is formatted by using FAT or FAT32 file systems. The operating system stores information about each file in the FAT so that it can retrieve the file later.
FAT32 file system: A derivative of the file allocation table (FAT) file system. FAT32 supports smaller cluster sizes and larger volumes than FAT, which results in more efficient space allocation on FAT32 volumes. FAT32 uses 32-bit addressing.
file stream: See main stream and named stream.
main stream: The place within a file where data is stored or the data stored therein. A main stream has no name. The main stream is what is ordinarily thought of as the contents of a file.
named stream: A place within a file in addition to the main stream where data is stored, or the data stored therein. File systems support a mode in which it is possible to open either the main stream of a file and/or to open a named stream. Named streams have different data than the main stream (and than each other) and can be read and written independently. Not all file systems support named streams. See also main stream.
NT backup file: A file that contains the representation of another file. It is made up of zero or more backup streams.
NT file system (NTFS): A proprietary Microsoft file system. For more information, see [MSFT-NTFS].
reparse point: An attribute that can be added to a file to store a collection of user-defined data that is opaque to NTFS or ReFS. If a file that has a reparse point is opened, the open will normally fail with STATUS_REPARSE, so that the relevant file system filter driver can detect the open of a file associated with (owned by) this reparse point. At that point, each installed filter driver can check to see if it is the owner of the reparse point, and, if so, perform any special processing required for a file with that reparse point. The format of this data is understood by the application that stores the data and the file system filter that interprets the data and processes the file. For example, an encryption filter that is marked as the owner of a file's reparse point could look up the encryption key for that file. A file can have (at most) 1 reparse point associated with it. For more information, see [MS-FSCC].
security descriptor: A data structure containing the security information associated with a securable object. A security descriptor identifies an object's owner by its security identifier (SID). If access control is configured for the object, its security descriptor contains a discretionary access control list (DACL) with SIDs for the security principals who are allowed or denied access. Applications use this structure to set and query an object's security status. The security descriptor is used to guard access to an object as well as to control which type of auditing takes place when the object is accessed. The security descriptor format is specified in [MS-DTYP] section 2.4.6; a string representation of security descriptors, called SDDL, is specified in [MS-DTYP] section 2.5.1.
serialize: The process of taking an in-memory data structure, flat or otherwise, and turning it into a flat stream of bytes. See also marshal.
sparse file: A file containing large sections of data composed only of zeros. This file is marked as a sparse file in the file system, which saves disk space by only allocating as many ranges on disk as are required to completely reconstruct the non-zero data. When an attempt is made to read in the nonallocated portions of the file (also known as holes), the file system automatically returns zeros to the caller.
staging file: The backup of the changed file or folder. It encapsulates the data and attributes associated with a replicated file or folder. By creating the staging file, File Replication Service (FRS) ensures that file data can be supplied to partners regardless of any activity that might prevent access to the original file. The staging files can be compressed to save disk space and network bandwidth during replication.
unnamed stream: See main stream.
MAY, SHOULD, MUST, SHOULD NOT, MUST NOT: These terms (in all caps) are used as defined in [RFC2119]. All statements of optional behavior use either MAY, SHOULD, or SHOULD NOT.