AppleDouble header file
A separate file in a filesystem containing the Apple resource fork for a related data file, developed by Apple for A/UX and therefore compatible with other filesystems including those mounted remotely. They are heavily used under Mac OS X .
This file is named the same as the data file, with "
._" prepended to the original name. These header files are automatically included in ZIP files under a hierarchy starting with "
__MACOSX" when utilizing the Finder's "Archive as..." function.
- from "A/UX Toolbox: Macintosh ROM Interface manual", Chapter 6 File Systems and File Formats
- identifies the magic number
0x00051607for AppleDouble files as the first 4 bytes in the file
- background and additional information
- MIME Encapsulation of Macintosh files - MacMIME