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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 systems include file copying methods to users; operating systems with graphical user interfaces (GUIs) 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 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 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 systems include file copying provisions in the user interface, like the command, "cp" in Unix and "COPY" in DOS; operating systems with a graphical user interface, or GUI, 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 interfaces (APIs) for copying files (like CopyFile and CopyFileEx in Windows API), 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. 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 since 1992,^[1] 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.

References

^ "Caldera OpenDOS Machine Readable Source Kit (M.R.S) 7.01". Caldera, Inc. 1997-05-01. Archived from the original on 2021-08-07. Retrieved 2022-01-02. [1] (NB. Actually implemented since DR DOS "Panther" on 1992-06-22, see COMCPY.C/DOSIF.ASM in the COMMAND.COM sources of OpenDOS 7.01.)

External links

Instructions on how to shadow files for Emacs

[Caldera_1997_DOSSRC-1] "Caldera OpenDOS Machine Readable Source Kit (M.R.S) 7.01". Caldera, Inc. 1997-05-01. Archived from the original on 2021-08-07. Retrieved 2022-01-02. [1] (NB. Actually implemented since DR DOS "Panther" on 1992-06-22, see COMCPY.C/DOSIF.ASM in the COMMAND.COM sources of OpenDOS 7.01.)

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+{{short description|Operation which creates a new digital file with contents identical to another}}
-{{Unreferenced stub|auto=yes|date=December 2009}}
+{{more citations needed|date=December 2009}}
+{{use dmy dates|date=December 2021|cs1-dates=y}}
+{{use list-defined references|date=January 2022}}
+In digital [[file management]], '''copying''' is a [[Computer_file#Operations|file operation]] that creates a new [[Computer file|file]] which has the same content as an existing file. Computer [[operating system]]s include file copying methods to users; operating systems with [[graphical user interface]]s ([[GUI]]s) often providing [[copy-and-paste]] or [[drag-and-drop]] methods of file copying. Operating systems may have specialized file-copying [[API]]s are usually able to tell the server to perform the copying locally, without sending file contents over the network, thus greatly improving performance.
-In the realm of computer file management, '''file copying''' is the creation of a new [[computer file|file]] which has the same content as an existing file.
+== Description ==
-All computer [[operating system]]s include file copying provisions in the user interface, like the command, "[[cp (Unix)|cp]]" in [[Unix]] and "[[copy (command)|copy]]" in [[MS-DOS]]; operating systems with a [[graphical user interface]], or [[GUI]], usually provide [[copy-and-paste]] or [[drag-and-drop]] methods of file copying.&nbsp; [[File manager]] applications, too, provide an easy way of copying files.
+'''File copying''' is the creation of a new '''copy [[computer file|file]]''' which has the same content as an existing file.
+=== Shadow ===
-Internally, however, while some systems have specialized [[Application programming interface|application programming interfaces]] ([[API]]s) for copying files (like CopyFile and CopyFileEx in [[Windows API]]), others (like Unix and MS-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]].&nbsp; 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.&nbsp; 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.&nbsp; Sometimes, remote file copying is performed with a specialized command, like "ncopy" in MS-DOS clients for [[Novell NetWare]].
+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 [[Disk mirroring|mirror]] 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 [[Disk mirroring|reasons]] 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 ==
-An even more complicated situation arises when one needs to copy files between two remote servers.&nbsp; The simple way is to read data from one server, and then to write the data to the second server.&nbsp;
+All computer [[operating system]]s include file copying provisions in the user interface, like the command, "[[cp (Unix)|cp]]" in [[Unix]] and "[[COPY (command)|COPY]]" in [[DOS]]; operating systems with a [[graphical user interface]], or [[GUI]], usually provide [[copy-and-paste]] or [[drag-and-drop]] methods of file copying.&nbsp; [[File manager]] applications, too, provide an easy way of copying files.
+== {{anchor|NCOPY}}Implementation ==
-{{DEFAULTSORT:File Copying}}
+Internally, however, while some systems have specialized [[application programming interface]]s ([[API]]s) for copying files (like CopyFile and CopyFileEx in [[Windows API]]), others (like Unix and DOS) fall back to simply reading the contents of the old file and writing it to the new file.
-[[Category:Computer file systems]]
-[[Category:Copyright law]]
+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]].&nbsp;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.&nbsp;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 (DOS command)|COPY]] command in some versions of [[DR-DOS]] since 1992,<ref name="Caldera_1997_DOSSRC"/> 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 ==
-{{Operating-system-stub}}
+* {{section link|Computer file#Moving methods}}
+* [[Core dump]]
+* [[Soft copy]]
+* [[Hard copy]]
+* [[List of file copying software]]
+* [[ln (Unix)]]
+* [[NTFS junction point]]
+* [[Zero copy]]
+== References ==
-[[ko:파일 복사]]
+{{Reflist|refs=
+<ref name="Caldera_1997_DOSSRC">{{cite web |title=Caldera OpenDOS Machine Readable Source Kit (M.R.S) 7.01 |publisher=[[Caldera (company)|Caldera, Inc.]] |date=1997-05-01 |url=https://archive.sundby.com/retro/DR-DOS/dossrc.zip |access-date=2022-01-02 |url-status=live |archive-url=https://web.archive.org/web/20210807095409/https://archive.sundby.com/retro/DR-DOS/dossrc.zip |archive-date=2021-08-07}}  [https://web.archive.org/web/20220102102656/https://archive.sundby.com/retro/OpenDOS/OPENDOS_7.01_CODE.ZIP] (NB. Actually implemented since [[DR DOS "Panther"]] on 1992-06-22, see COMCPY.C/DOSIF.ASM in the COMMAND.COM sources of [[OpenDOS 7.01]].)</ref>
+}}
+== Further reading ==
+* [http://www.freepatentsonline.com/5043876.html N-level file shadowing and recovery in a shared file system], United States Patent 5043876
+* [http://www.freepatentsonline.com/5276871.html Method of file shadowing among peer systems], United States Patent 5276871
+* [https://web.archive.org/web/20061127130733/http://www.ibexpert.info/documentation/%20%209.%20IBExpert%20Services%20Menu/%20%202.%20Restore%20Database/%20%201.%20Database%20Shadow%20Files/15713.html Database Shadow Files]
+== External links ==
+* [https://www.gnu.org/software/emacs/manual/html_node/emacs/File-Shadowing.html Instructions on how to shadow files] for [[Emacs]]
+{{Computer files}}
+{{DEFAULTSORT:File Copying}}
+[[Category:Computer file systems]]
+[[Category:Copyright law]]

v t e Computer files
Types	Binary file / text file Data file File format List of file formats File signatures Magic number Open file formats Proprietary file formats Metafile Sidecar file Sparse file Swap file System file Temporary file Zero-byte file
Properties	Filename 8.3 filename Long filename Filename mangling Filename extension List of filename extensions File attribute Extended file attributes File size Hidden file / Hidden directory
Organisation	Directory/folder NTFS links Temporary folder Directory structure File system Filesystem Hierarchy Standard Grid file system Semantic file system Path
Operations	Open Close Read Write
Linking	File descriptor Hard link Shortcut Alias Shadow Symbolic link
Management	Backup File comparison File copying Data compression File manager Comparison of file managers File system fragmentation File-system permissions File transfer File sharing File synchronization File verification