Maconv/docs/formats/AppleSingle.md

AppleSingle format

AppleSingle is a file format developed to store Mac OS "dual-forked" files on the Unix filesystem. AppleSingle is similar in concept to the more popular MacBinary format, in that the resource and data forks are combined together with a header containing the Finder information. In fact, the format is so similar, it seemed there were no reason why Apple did not simply use MacBinary instead, which by that point, was widely known and used.

All integers are big-endians.

Data are arranged as follows:

data = <file header> + <entry 1> + ... + <entry N> + <data 1> + ... + <data N>

File header

Offset	Length	Contents
00	Word	Magic number (always 0x00051600)
04	Word	Version number (always 0x00020000)
08	16 Bytes	Always zero
24	Half	Number of entries

Entry

Offset	Length	Contents
00	Word	Entry ID (see below)
04	Word	Data offset
08	Word	Data length (can be zero)

Available entry IDs are described in the following table.

Entry name	ID	Description
Data Fork	1	Magic number (always 0x00051600)
Resource Fork	2	Version number (always 0x00020000)
Real Name	3	File’s name as created on home file system
Comment	4	Standard Macintosh comment
Icon, B&W	5	Standard Macintosh black and white icon
Icon, Color	6	Macintosh color icon
File Dates Info	8	File creation date, modification date, and so on
Finder Info	9	Standard Macintosh Finder information
Macintosh File Info	10	Macintosh file information, attributes, and so on
ProDOS File Info	11	ProDOS file information, attributes, and so on
MS-DOS File Info	12	MS-DOS file information, attributes, and so on
Short Name	13	AFP short name
AFP File Info	14	AFP file information, attributes, and so on
Directory ID	15	AFP directory ID

---

Sources

https://en.wikipedia.org/wiki/AppleSingle_and_AppleDouble_formats http://kaiser-edv.de/documents/AppleSingle_AppleDouble.pdf