- Type code
A type code is the only mechanism used in pre-
Mac OS X versions of the Macintoshoperating system to denote a file's format, in a manner similar tofile extension s in other operating systems. Codes are four-byteOSType s. For example, the type code for aHyperCard stack is STAK; the type code of any application program is APPL.Mac OS X retains type codes, but supports filename extensions as well. The deprecation of type codes (and
creator code s) over the older extension system, popularised byPDP-11 systems (RT-11 ,RSX-11 , etc.),CP/M , and most recently byMicrosoft 'sDOS , has been very controversial with Mac users. The type and creator system is considerably richer and more sophisticated than that provided by extensions, and many users felt that adopting DOS conventions is a backward step. They claim that type and creator information rightfully belongs to the metadata associated with a file, and is therefore illogically placed within the file's name, where its presence can cause problems for the user. Apple defends the decision by saying that extensions have become the "de facto" standard for indicating file type, and they need to work seamlessly with the rest of the industry.Type codes are not readily accessible for users to manipulate, although they can be viewed and changed with certain software, most notably the Mac OS X command line tools "GetFileInfo" and "SetFile" which are installed as part of the developer tools into "/Developer/Tools", or the
ResEdit utility available for older Macs.Changes done in
Mac OS X v10.4 with the addition ofUniform Type Identifier s suggest that Apple heard those criticisms and is working on a file type successor to both type code and filename extensions. [http://arstechnica.com/reviews/os/macosx-10.4.ars/11]External links
* [http://homepage.mac.com/tcdb/ The Type/Creator Database Website]
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