[Pharo-users] What is "Primitives"?

Looking at the code for DiskStore>>basicEntryAt: I find this code: "Primitives lookupDirectory: encodedPath filename: encodedBasename)" What is this "Primitives" not a class? I am suprised there is some code that I can not find the source for. Ok, it has something to do with vm primitives, and I know that code like <primitive: 'primitiveDirectoryEntry' module: 'FilePlugin'> is in the vmmaker-package for FilePlugin. BTW it is terrible hard to load vmmaker in a "normal" image. Now I use the generator.image from pharo http://files.pharo.org/vm/src/. But even in this image it is not possible to load the vmmaker tool.