Macintosh resource file

File Format
Name	Macintosh resource file
Ontology	Electronic File Formats Development Macintosh resource file
Extension(s)	.rsrc, .dfont

The Macintosh resource file format was used by the Resource Manager in Mac OS Classic for storing resources used by Mac OS Classic applications as well as file associations and executable code. Traditionally, this format is used in the Resource Fork of a file on the HFS and HFS+ file systems; however, when resource files are still used in Mac OS X applications, the same format is used in a file with the extension .rsrc.

Format details

A resource has a four-character type code, an ID, and data. The type code is generally unique to the type of data stored within, but this may not be the case with application-specific formats.

References

• Resource fork (Wikipedia)
• More Macintosh Toolbox (format is described on page 1-121 to 1-125)
• KSFL reads and writes Macintosh resource files
• Description of the file format from the KSFL wiki