The PowerPC Reference Platform and machine abstractions

The PowerPC Reference Platform specification is an open specification whose goal is to create an industry standard for building PowerPC based computer systems. This standard allows for compatible differentiation between systems, that is, the ability for systems designers to substantially differentiate their hardware platform from other systems and still remain compatible with targeted operating systems and their applications. This is achieved largely through the use of machine abstractions which isolate the operating system from the areas of hardware most likely to change.<>