Developers

Individual developers work on a particular piece of code. For example, you could be an expert in how your digital camera works. So you might work on the USB device driver that handles your camera.

• Maintainers work on subsystems. There is a list of kernel maintainers [8]. They handle such things as the quota subsystem, the block device drivers, the PPC64 architecture, etc. The whole kernel is broken up into areas of responsibility. Maintainers accept changes (patches) from individual developers, apply them, test them, and integrate them into larger changesets to be forwarded upward.

• Linus Torvolds is the top of the development pile. He only accepts changes that have come thru the appropriate maintainers and then only if he agrees with them. Thus he controls what goes into the official kernel. There are people, like Andrew Morten, that maintain their own ``branch'' of the kernel. The Morten kernel can be built using the ``-mm'' switch which includes and/or excludes certain things that Linus has not accepted.