- Directory (file systems)
computing, a directory, catalog, folder ["With the introduction of Windows 95, Microsoft started referring to directories as folders." (" [http://www.murach.com/books/csh5/ Murach's C# 2005] ", page 34)] or drawer [Name used in AmigaOSWorkbench.] is an entity in a file system, which contains a group of files and/or other directories. A typical file system may contain thousands (or even hundreds of thousands) of directories. Files are kept organized by storing related files in the same directory. A directory contained inside another directory is called a "subdirectory" of that directory. Together, the directories form a hierarchy, or tree structure.
A computer's file system can be visualized as a file cabinet, where high-level directories are represented by the drawers and lower-level subdirectories may be represented as file folders within the drawers.
Historically, and even on some modern
embedded devices, the filesystems either have no support for directories at all or only have a flat directory structure, meaning subdirectories are not allowed; there is only a group of top-level directories each containing files. The first popular fully general hierarchical filesystem was that of UNIX. This type of filesystem was an early research interest of Dennis Ritchie.
In modern times in
Unix-likesystems, especially Linux, directory structure is defined by the Filesystem Hierarchy Standard.
operating systems, programs have an associated current working directoryin which they execute. Typically filenames accessed by the program are assumed to reside within this directory if the filenames are not specified with an explicit directory name.
Some operating systems restrict a user's access to only their
home directoryor project directory, thus isolating their activities from all other users.
On Unix, directories are regarded as a type of file. ["Everything is a File" (" [http://www.uwsg.indiana.edu/usail/concepts/filesystems/everything-is-a-file.html Unix System Administration Independent Learning] ")]
The folder metaphor
The name "folder", presenting an analogy to the
file folderused in offices, and used originally by Apple Lisa[http://blog.modernmechanix.com/2008/05/29/the-lisa-computer-system-apple-designs-a-new-kind-of-machine/ "Apple Designs a New Kind of Machine"] , is used in almost all modern operating systems' desktop environments. Folders are often depicted with icons which visually resemble physical file folders.
Strictly speaking, there is a difference between a "directory" which is a
file systemconcept, and the graphical user interfacemetaphor that is used to represent it (a "folder"). For example, Microsoft Windows uses the concept of special folders to help present the contents of the computer to the user in a fairly consistent way that frees the user from having to deal with absolute directory paths, which can vary between versions of Windows, and between individual installations.
* [http://www.bellevuelinux.org/directory.html Definition of directory] by The Linux Information Project (LINFO)
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