Editing Macintosh Toolbox (section)

=== On PowerPC systems ===
In 1994, Apple released Macintoshes using the [[PowerPC]] architecture, which lacked hardware support for the A-trap mechanism available on 68k systems. Because of their use in applying software patches, however, the dispatch tables were retained. The API library code underlying any Toolbox routine then does nothing except reference the dispatch table. The dispatch table linked only to emulated 68000 family code. Toolbox functions implemented in native PowerPC code have to first disable the emulator using the Mixed Mode Manager. For the sake of uniformity and extensibility, new function entries even continued to be added to the Toolbox after the PowerPC transition.

An alternative mechanism did exist, however, in the Code Fragment Manager, which was used to load and dynamically link native PowerPC programs. The PowerPC system call facility, analogous to the A-trap mechanism, was used to interface with the [[Mac OS nanokernel]], which offered few services directly useful to applications.