HOME

TheInfoList



OR:

In digital file management, copying is a file operation that creates a new file which has the same content as an existing file. Computer
operating system An operating system (OS) is system software that manages computer hardware, software resources, and provides common daemon (computing), services for computer programs. Time-sharing operating systems scheduler (computing), schedule tasks for ef ...
s include file copying methods to users, with operating systems with
graphical user interface The GUI ( "UI" by itself is still usually pronounced . or ), graphical user interface, is a form of user interface that allows users to interact with electronic devices through graphical icons and audio indicator such as primary notation, ins ...
s (
GUI The GUI ( "UI" by itself is still usually pronounced . or ), graphical user interface, is a form of user interface that allows users to interact with electronic devices through graphical icons and audio indicator such as primary notation, inste ...
s) often providing copy-and-paste or drag-and-drop methods of file copying. Operating systems may have specialized file copying APIs are usually able to tell the server to perform the copying locally, without sending file contents over the network, thus greatly improving performance.


Description

File copying is the creation of a new copy file which has the same content as an existing file.


Shadow

There are several different technologies that use the term shadowing, but the intent of shadowing within these technologies is to provide an exact copy (or
mirror A mirror or looking glass is an object that reflects an image. Light that bounces off a mirror will show an image of whatever is in front of it, when focused through the lens of the eye or a camera. Mirrors reverse the direction of the im ...
of a set) of data. For shadowing to be effective, the shadow needs to exist in a separate physical location than the original data. Depending on the
reasons In the most general terms, a reason is a consideration which justifies or explains an action, a belief, an attitude, or a fact. ''Normative reasons'' are what people appeal to when making arguments about what people should do or believe. For exam ...
behind the shadow operation, this location may be as close as the BIOS chip to the RAM modules, a second harddrive in the same chassis, or as far away as the other side of the globe.


Use

All computer
operating system An operating system (OS) is system software that manages computer hardware, software resources, and provides common daemon (computing), services for computer programs. Time-sharing operating systems scheduler (computing), schedule tasks for ef ...
s include file copying provisions in the user interface, like the command, " cp" in
Unix Unix (; trademarked as UNIX) is a family of multitasking, multiuser computer operating systems that derive from the original AT&T Unix, whose development started in 1969 at the Bell Labs research center by Ken Thompson, Dennis Ritchie, ...
and " COPY" in DOS; operating systems with a
graphical user interface The GUI ( "UI" by itself is still usually pronounced . or ), graphical user interface, is a form of user interface that allows users to interact with electronic devices through graphical icons and audio indicator such as primary notation, ins ...
, or
GUI The GUI ( "UI" by itself is still usually pronounced . or ), graphical user interface, is a form of user interface that allows users to interact with electronic devices through graphical icons and audio indicator such as primary notation, inste ...
, usually provide copy-and-paste or drag-and-drop methods of file copying.  File manager applications, too, provide an easy way of copying files.


Implementation

Internally, however, while some systems have specialized
application programming interface An application programming interface (API) is a way for two or more computer programs to communicate with each other. It is a type of software interface, offering a service to other pieces of software. A document or standard that describes how ...
s ( APIs) for copying files (like CopyFile and CopyFileEx in
Windows API The Windows API, informally WinAPI, is Microsoft's core set of application programming interfaces (APIs) available in the Microsoft Windows operating systems. The name Windows API collectively refers to several different platform implementations th ...
), others (like Unix and DOS) fall back to simply reading the contents of the old file and writing it to the new file. This makes little difference with local files (those on the computer's hard drive), but provides an interesting situation when both the source and target files are located on a remote
file server In computing, a file server (or fileserver) is a computer attached to a network that provides a location for shared disk access, i.e. storage of computer files (such as text, image, sound, video) that can be accessed by the workstations that are ab ...
. Operating systems with specialized file copying APIs are usually able to tell the server to perform the copying locally, without sending file contents over the network, thus greatly improving performance. Those systems that have no comparable APIs, however, have to read the file contents over the network, and then send them back again, over the network. Sometimes, remote file copying is performed with a specialized command, like "NCOPY" in DOS clients for Novell NetWare. The COPY command in some versions of
DR-DOS DR-DOS (written as DR DOS, without a hyphen, in versions up to and including 6.0) is a disk operating system for IBM PC compatibles. Upon its introduction in 1988, it was the first DOS attempting to be compatible with IBM PC DOS and MS- ...
since 1992, has built-in support for this. An even more complicated situation arises when one needs to copy files between two remote servers. The simple way is to read data from one server, and then to write the data to the second server.


See also

* * Core dump *
Soft copy ''Hard Copy'' is an American tabloid television show that ran in syndication from 1989 to 1999. ''Hard Copy'' was aggressive in its use of questionable material on television, including gratuitous violence. The original hosts of ''Hard Copy'' ...
* Hard copy * List of file copying software * ln (Unix) * NTFS junction point * Zero copy


References


Further reading


N-level file shadowing and recovery in a shared file system
United States Patent 5043876

United States Patent 5276871


External links



for
Emacs Emacs , originally named EMACS (an acronym for "Editor MACroS"), is a family of text editors that are characterized by their extensibility. The manual for the most widely used variant, GNU Emacs, describes it as "the extensible, customizable, ...
{{DEFAULTSORT:File Copying Computer file systems Copyright law