It is a shared information infrastructure for locating, managing, administering and organizing everyday items and network resources, which can include volumes, folders, files, printers, users, groups, devices, telephone numbers and other objects.
[citation needed] Therefore, directory applications try to reuse standard classes and attributes to maximize the benefit of existing directory-server software.
Directory services are often central to the security design of an IT system and have a correspondingly-fine granularity of access control.
Directory services were part of an Open Systems Interconnection (OSI) initiative for common network standards and multi-vendor interoperability.
During the 1980s, the ITU and ISO created the X.500 set of standards for directory services, initially to support the requirements of inter-carrier electronic messaging and network-name lookup.