Applesingle and AppleDouble format internals

The following is copied from “A/UX Toolbox: Macintosh ROM Interface manual”, Chapter 6 File Systems and File Formats, pages 6-16 to 6-19. It’s available in a printable version , too.

Applesingle format stores the data, resources, and attributes of a Macintosh file in a single A/UX file. AppleDouble format stores a file’s data in one file and stores its resources and attributes in another file.