AppleSingle

File Format
Name	AppleSingle
Ontology	Electronic File Formats Archiving AppleSingle
Extension(s)	.as, others
MIME Type(s)	application/applefile
PRONOM	fmt/967, fmt/968
Kaitai Struct Spec	apple_single_double.ksy
Released	1990

AppleSingle is one of the systems used to store the Resource Fork of Macintosh files on filesystems not natively supporting it, something which became necessary when Apple moved to Unix-based operating systems instead of "classic" MacOS. AppleDouble is an alternative format to accomplish the same end, using two files where AppleSingle uses one.

AppleSingle combines the data and resource forks with Finder meta-information into a single file, similar in concept to MacBinary.

Identification

AppleSingle files begin with signature bytes (hex) 00 05 16 00.

Specifications

Refer to AppleDouble#Specifications.

Utilities

• Mac Binary Converter
• Mac::AppleSingleDouble Perl library

Other links

• Wikipedia article
• MacBinary and Binhex 4.0 considered harmful
• Discussion and sample files on creating a DROID signature for AppleSingle