directoryentrees

A directory entry is a data item stored within a directory that associates a human-readable name with a reference to an object stored elsewhere in a system. The exact contents and purpose of a directory entry depend on the type of directory in use, but the common idea is to enable the system to locate objects by name and then access their metadata.

In file systems, directories act as containers for directory entries that map file or subdirectory names to the objects they represent. Each entry typically stores the name and a pointer or identifier to the object's metadata, such as an inode number in Unix-like systems or a file record in Windows NTFS. Directory entries are used during path resolution, opening files, and listing directory contents. Modern file systems often employ indexing trees to keep lookups fast as a directory grows, and they may support features like hard links and symbolic links that affect how entries reference objects.

In directory services, directory entries represent objects such as users, groups, devices, or services, along with their attributes (for example, a user’s login name, email, and group memberships). These entries are organized hierarchically and identified by a distinguished name or similar identifier. Operations on directory entries include create, read, update, delete, and search, and access control policies regulate who may view or modify them. Directory services rely on schemas that define permissible object classes and attributes to maintain consistency across the directory.

Overall, directory entries are fundamental to how systems map human-readable names to underlying data objects, enabling organization, lookup, and access control across both filesystems and directory services.