| In this chapter, we looked at the I/O subsystem from a variety of levels. We covered some of the physical and architectural aspects of the I/O system, looking at how modules are accessed, addressed, and claimed by drivers. We looked at how the I/O portion of the kernel is made up of a complex framework consisting of the GIO, which acts as interface and overseer; a variety of CDIOs, which encapsulate the drivers; and the CB CDIO, which manages the platform-specific parts of the I/O system. Finally, we looked at how I/O requests work their way through the system from a user request to a device special file to the device switch tables and into the correct driver. All this gives us a more detailed look at some of the I/O interfaces we touched on in earlier chapters. Chapter 15, "System Initialization," looks at how this fits in with the other things that happen at boot time. |