8.3 file name
A standard for naming files first introduced with MS-DOS operating systems. The numbers indicate the maximum number of characters that can be used for that part of the name, eight characters and three characters respectively. The period is a separator character between the two names. The three-character field is also known as the file extension.
Access Control Entries (ACE)
A specific entry in a file or folder's ACL that uniquely identifies a user or group by its security identifier and the action it is allowed or denied to take on that file or folder.
Access Control List (ACL)
For those file systems that support ACLs for files and folders, such as NTFS, the ACL is a property of every file and folder in that file system. It holds a collection (that is, list) of ACE items that explicitly defines what actions are allowed to be taken on the file or folder to which it is attached.
Disk quota
A system of tracking owners for file data within an NTFS-formatted partition or volume and the total disk space consumed by each owner. Limits or warnings can be established to restrict disk space usage.
Drive letter
A letter of the alphabet assigned to a formatted partition or volume as a reference point for future access by the user or their applications.
Encrypted File System (EFS)
A component of the NTFS file system that is responsible for encrypting individual files. These files are not readable without the correct digital identification.
Extended File Allocation Table (exFAT)
A proprietary Microsoft file system used with external storage media to organize files and folders using a technology similar to FAT but without the space limitations of FAT32. Volume sizes over 32 GB are fully supported.
FAT
A generic term that refers to early versions of the FAT file system (FAT12, FAT16) or to any FAT file system in general, also see File Allocation Table.
File Allocation Table (FAT)
A file system used to organize files and folders in a partition or volume. A master File Allocation Table is used to indicate what files and folders exist within the file system. The FAT table entries point to the beginning cluster used to store a file's data. The first cluster points to the next cluster used to store the next part of the file's data. The file's data is stored in a chain of clusters, with the last cluster marked with an end-of-file identifier. The FAT table stores the name and attributes of the files and folders on the disk, their starting cluster, and which clusters link to the next. The number of addressable clusters determines the size of the FAT table. The limit for how many addressable clusters exist is based on the size of the binary number used to address each cluster. The number of bits used for the cluster address distinguishes the different versions of FAT. The common versions of FAT include FAT16 and FAT32.
File extension
Typically a three-character name at the end of a filename that is used to indicate the type of data contained in the file. Common extension examples include DOC for documents and EXE for executable programs.
Long filenames
Filenames that can be a maximum of 255 characters in length.
New Technology File System (NTFS)
A file system introduced with Windows NT. NTFS supports advanced features to add reliability, security, and flexibility that file systems such as FAT and FAT32 do not have.
Shadow copy
A snapshot of the file system that tracks changes to files and allows the restoration of previous file versions.
Terabyte
A unit of data that consists of 1024 gigabytes. Commonly abbreviated as TB.