Computer file management

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The term computer file management refers to the manipulation of documents and data in files on a computer. Specifically, one may create a new file or edit an existing file and save it; open or load a pre-existing file into memory; or close a file without saving it. Additionally, one may group related files in directories or folders. These tasks are accomplished in different ways in different operating systems and depend on the user interface design and, to some extent, the storage medium being used.

[edit] Paradigms of file management

Although the file management paradigm described above is currently the dominant one in computing, attempts have been made to create more efficient or usable paradigms. The concept of saving a file, in particular, has been the subject of much innovation, with some applications including an auto-save feature (to periodically save changes to a file in case of a computer crash, power outage, etc.) and others doing away with the save concept completely. In the latter case, one typically opens and closes files without ever being given the option to save them. Such applications usually have a multi-level undo feature to replace the concept of closing a file without saving any changes.

[edit] Concept of the hierarchy of files

Files can also be managed based on their location on a storage device. They are stored in a storage medium in binary form. Physically, the data is placed in a not-so-well organized structure, due to fragmentation. However, the grouping of files into directories (for operating systems such as DOS, Unix, Linux) or folders (for the Mac OS and Windows) are done by changing an index of file information known as the File Allocation Table (NTFS for recent versions of Windows) or Master File Table (depending on operating system used). In this index, the physical location of a particular file on the storage medium is stored, as well as its position in the hierarchy of directories (as we see it using commands such as DIR, LS and programs such as Explorer, Finder).

The DOS/Windows hierarchy is different from the implementation of the Unix/Linux hierarchy.

For DOS/Windows, the hierarchy (along with examples):

Drive (C:)
- Directory/Folder (C:\My Documents)
  - Sub-directory/Sub-folder (C:\My Documents\My Pictures)
    - File (C:\My Documents\My Pictures\VacationPhoto.jpg)

On Unix/Linux machines, the hierarchy is:

The root directory (/)
- Directories (/usr "user" or /dev "device")
  - Sub-directories (/usr/local)
    - Files: data, devices, links, etc. (/usr/local/readme.txt or /dev/hda1, which is the hard disk device)