Assoc De La Moreria Reial De Lleida A L'Edat Mitjana - Muhamed Ibrahim Bosch
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In
computing Computing is any goal-oriented activity requiring, benefiting from, or creating computing machinery. It includes the study and experimentation of algorithmic processes, and development of both hardware and software. Computing has scientific, ...
, a file association associates a file with an application capable of opening that file. More commonly, a file association associates a class of files (usually determined by their
filename extension A filename extension, file name extension or file extension is a suffix to the name of a computer file (e.g., .txt, .docx, .md). The extension indicates a characteristic of the file contents or its intended use. A filename extension is typically ...
, such as
.txt A text file (sometimes spelled textfile; an old alternative name is flatfile) is a kind of computer file that is structured as a sequence of lines of electronic text. A text file exists stored as data within a computer file system. In operat ...
) with a corresponding application (such as a
text editor A text editor is a type of computer program that edits plain text. Such programs are sometimes known as "notepad" software (e.g. Windows Notepad). Text editors are provided with operating systems and software development packages, and can be ...
).


Associations and verbs

A single file extension may have several associations for performing various actions, also known as verbs. Some of the common verbs are: * ''open'' to open a file * ''edit'' to open a file for editing * ''print'' to print a file A
picture An image is a visual representation of something. It can be two-dimensional, three-dimensional, or somehow otherwise feed into the visual system to convey information. An image can be an artifact, such as a photograph or other two-dimensiona ...
, for example, may be associated with these words so that ''open'' opens the picture in an
image viewer An image viewer or image browser is a computer program that can display stored graphical images; it can often handle various graphics file formats. Such software usually renders the image according to properties of the display such as color depth, ...
, ''edit'' opens up an
image editing Image editing encompasses the processes of altering images, whether they are digital photographs, traditional photo-chemical photographs, or illustrations. Traditional analog image editing is known as photo retouching, using tools such as a ...
program and ''print'' sends the picture to a printer.


Implementations

Most operating systems support file associations in some form or the other. For example, opening a file from a file manager usually invokes the ''open'' verb in order to open the file with its associated application. The "open" verb invokes the associated
application program Application may refer to: Mathematics and computing * Application software, computer software designed to help the user to perform specific tasks ** Application layer, an abstraction layer that specifies protocols and interface methods used in a c ...
, which reads the file or document and presents it to the user for viewing, and possibly for editing or other action. Additional actions such as ''print'' are usually accessed via a right-click
context menu A context menu (also called contextual, shortcut, and pop up or pop-up menu) is a menu in a graphical user interface (GUI) that appears upon user interaction, such as a right-click mouse operation. A context menu offers a limited set of choic ...
. A mechanism for modifying associations is also usually present. An example for this is the ''Open With'' option in the
Windows Shell The Windows shell is the graphical user interface for the Microsoft Windows operating system. Its readily identifiable elements consist of the desktop, the taskbar, the Start menu, the task switcher and the AutoPlay feature. On some versions of W ...
.


Microsoft Windows

The Microsoft Windows series of
operating system An operating system (OS) is system software that manages computer hardware, software resources, and provides common services for computer programs. Time-sharing operating systems schedule tasks for efficient use of the system and may also i ...
s, beginning with
Windows 3.x Windows 3.x means either of, or all of the following versions of Microsoft Windows: * Windows 3.0 * Windows 3.1x Windows 3.1 is a major release of Microsoft Windows. It was released to manufacturing on April 6, 1992, as a successor to Windo ...
supports file extension-based associations. Associations are stored in
registry Registry may refer to: Computing * Container registry, an operating-system-level virtualization registry * Domain name registry, a database of top-level internet domain names * Local Internet registry * Metadata registry, information system for re ...
as sets of verbs for each file extension. Older versions supported ''open'' associations stored in WIN.INI. File associations can be displayed and edited using the assoc
command Command may refer to: Computing * Command (computing), a statement in a computer language * COMMAND.COM, the default operating system shell and command-line interpreter for DOS * Command key, a modifier key on Apple Macintosh computer keyboards * ...
and with the help of the
ftype __NOTOC__ In computing, ftype is a command-line utility on Microsoft Windows that is used to display or change the link between a file type and an executable program. Overview The ftype command was introduced as a shell builtin to cmd.exe with t ...
command it is possible to create association between file type and application which will open files of this type. The Windows shell invokes file association actions through COM, drag and drop, command line calls or through
Dynamic Data Exchange In computing, Dynamic Data Exchange (DDE) is a technology for interprocess communication used in early versions of Microsoft Windows and OS/2. DDE allows programs to manipulate objects provided by other programs, and respond to user actions affec ...
. Advanced features of Microsoft Windows file associations included manually defining a new file extension with any number of associated actions, a primary ''default action'', showing extensions only for specific file types, customizing the file type icon and description and customizing associated
MIME Multipurpose Internet Mail Extensions (MIME) is an Internet standard that extends the format of email messages to support text in character sets other than ASCII, as well as attachments of audio, video, images, and application programs. Message ...
type and their handling (how to handle file types for files downloaded or directly opened from within the
Internet Explorer Internet Explorer (formerly Microsoft Internet Explorer and Windows Internet Explorer, commonly abbreviated IE or MSIE) is a series of graphical web browsers developed by Microsoft which was used in the Windows line of operating systems ( ...
browser). The ability to configure advanced file association functionality, however, was removed in
Windows Vista Windows Vista is a major release of the Windows NT operating system developed by Microsoft. It was the direct successor to Windows XP, which was released five years before, at the time being the longest time span between successive releases of ...
and later operating systems.


Linux

Linux Linux ( or ) is a family of open-source Unix-like operating systems based on the Linux kernel, an operating system kernel first released on September 17, 1991, by Linus Torvalds. Linux is typically packaged as a Linux distribution, w ...
-based GUIs, such as
KDE KDE is an international free software community that develops free and open-source software. As a central development hub, it provides tools and resources that allow collaborative work on this kind of software. Well-known products include the ...
and GNOME, support MIME type-based associations. For example, the MIME type text/plain would be associated with a
text editor A text editor is a type of computer program that edits plain text. Such programs are sometimes known as "notepad" software (e.g. Windows Notepad). Text editors are provided with operating systems and software development packages, and can be ...
.


Mac OS

The Classic Mac OS used
type code The resource fork is a fork or section of a file on Apple's classic Mac OS operating system, which was also carried over to the modern macOS for compatibility, used to store structured data along with the unstructured data stored within the data f ...
s and
creator code A creator code is a mechanism introduced in the classic Mac OS to link a data file to the application program which created it. The similar type code held the file type, like "TEXT". Together, the type and creator indicated what application sho ...
s to associate each file with its corresponding application, regardless of file extension. The more recent
macOS macOS (; previously OS X and originally Mac OS X) is a Unix operating system developed and marketed by Apple Inc. since 2001. It is the primary operating system for Apple's Mac computers. Within the market of desktop and lapt ...
also supports file extension–based associations. Application bundles in macOS declare supported file types in their Info.plist file. For each of these specified types, a
Uniform Type Identifier A Uniform Type Identifier (UTI) is a text string used on software provided by Apple Inc. to uniquely identify a given class or type of item. Apple provides built-in UTIs to identify common system objects – document or image file types, folders ...
is given, along with a list of 'tags' which define how a file or data of this type could be identified. For example, the JPEG type is defined with a UTI of 'public.jpeg', and tagged with the extensions 'jpg' and 'jpeg', the
MIME Multipurpose Internet Mail Extensions (MIME) is an Internet standard that extends the format of email messages to support text in character sets other than ASCII, as well as attachments of audio, video, images, and application programs. Message ...
type 'image/jpeg' and the
type code The resource fork is a fork or section of a file on Apple's classic Mac OS operating system, which was also carried over to the modern macOS for compatibility, used to store structured data along with the unstructured data stored within the data f ...
'JPEG'.Mac OS X Reference Library - Uniform Type Identifier Concepts
/ref> The operating system uses this information to generate a list of applications which are able to open each type. Within
Finder (software) The Finder is the default file manager and graphical user interface shell used on all Macintosh operating systems. Described in its "About" window as "The Macintosh Desktop Experience", it is responsible for the launching of other application ...
each file will be identified with a UTI and open with the default application for that type. The user may also select from a list of other applications which support the type. Using this system, types are also associated with data for which there is no file name or the file extension is missing. This includes pasteboard data and data streaming over a protocol such as
HTTP The Hypertext Transfer Protocol (HTTP) is an application layer protocol in the Internet protocol suite model for distributed, collaborative, hypermedia information systems. HTTP is the foundation of data communication for the World Wide We ...
where a MIME type has been given.


See also

* File format *
Filename extension A filename extension, file name extension or file extension is a suffix to the name of a computer file (e.g., .txt, .docx, .md). The extension indicates a characteristic of the file contents or its intended use. A filename extension is typically ...


References


Further reading

# # {{DEFAULTSORT:File Association Metadata