A creator code is a mechanism introduced in the

classic Mac OS Mac OS (originally System Software; retronym: Classic Mac OS) is the series of operating systems developed for the Macintosh family of personal computers by Apple Computer from 1984 to 2001, starting with System 1 and ending with Mac OS 9. The ...

to link a data file to the application program which created it. The similar

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 fo ...

held the file type, like "TEXT". Together, the type and creator indicated what application should be used to open a file, similar to (but richer than) the file extensions in other operating systems. Creator codes are four-byte

OSType A FourCC ("four-character code") is a sequence of four bytes (typically ASCII) used to uniquely identify data formats. It originated from the OSType or ResType metadata system used in classic Mac OS and was adopted for the Amiga/Electronic Arts I ...

s. They allow applications to launch and open a file whenever any of their associated files is double-clicked. Creator codes could be any four-byte value, but were usually chosen so that their

ASCII ASCII ( ), abbreviated from American Standard Code for Information Interchange, is a character encoding standard for electronic communication. ASCII codes represent text in computers, telecommunications equipment, and other devices. Because of ...

representation formed a word or acronym. For example, the creator code of the HyperCard application and its associated "stacks" is represented in

as , from the application's original name of WildCard. Occasionally they represented

inside joke An in-joke, also known as an inside joke or a private joke, is a joke whose humour is understandable only to members of an ingroup; that is, people who are ''in'' a particular social group, occupation, or other community of shared interest. It i ...

s. For instance, the ''

Marathon The marathon is a long-distance foot race with a distance of , usually run as a road race, but the distance can be covered on trail routes. The marathon can be completed by running or with a run/walk strategy. There are also wheelchair div ...

'' computer game had a creator code of (the approximate length, in miles, of a

marathon The marathon is a long-distance foot race with a distance of , usually run as a road race, but the distance can be covered on trail routes. The marathon can be completed by running or with a run/walk strategy. There are also wheelchair div ...

) and '' Marathon 2: Durandal'' had a creator code of . The binding are stored inside the resource fork of the application as BNDL and fref resources. These resources maintained the creator code as well as the association with each

and

icon An icon () is a religious work of art, most commonly a painting, in the cultures of the Eastern Orthodox, Oriental Orthodox, and Catholic churches. They are not simply artworks; "an icon is a sacred image used in religious devotion". The most ...

. The OS collected this data from the files when they were copied between mediums, thereby building up the list of associations and icons as software was installed onto the machine. Periodically this "desktop database" would become corrupted, and had to be fixed by "rebuilding the desktop database." The key difference between extensions and Apple's system is that file type and file ownership bindings are kept distinct. This allows files to be written of the same type - TEXT say - by different applications. Although any application can open anyone else's TEXT file, by default, opening the file will open the original application that created it. With the extensions approach, this distinction is lost - all files with a .txt extension will be mapped to a single text editing application of the user's choosing. A more obvious advantage of this approach is allowing for

double click A double-click is the act of pressing a computer mouse button twice quickly without moving the mouse. Double-clicking allows two different actions to be associated with the same mouse button. It was developed by Bill Atkinson of Apple Computer (n ...

launching of specialized editors for more complex but common file types, like .csv or .html. This can also represent a disadvantage as in the illustration above, where double clicking the four mp3 files would launch and play the files in four different music applications instead of queuing them in the user's preferred player application. macOS retains creator codes, but supports extensions as well. However, beginning with Mac OS X Snow Leopard, creator codes are ignored by the operating system. Creator codes have been internally superseded by Apple's

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 a ...

scheme, which manages application and file type identification as well as type codes, creator codes and file extensions. To avoid conflicts, Apple maintained a database of creator codes in use. Developers could fill out an online form to register their codes. Apple reserves codes containing all lower-case ASCII characters for its own use. Creator codes are not readily accessible for users to manipulate, although they can be viewed and changed with certain software, most notably the macOS command line tools ''GetFileInfo'' and ''SetFile'' which are installed as part of the developer tools into ''/Developer/Tools''.

References

External links

How application binding policy changed in Snow Leopard
* {{Mac OS Macintosh operating systems Metadata

See also

References

External links