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What Is the I/O Kit?

The I/O Kit is a collection of system frameworks, libraries, tools, and other resources for creating device drivers in Mac OS X. It is based on an object-oriented programming model implemented in a restricted form of C++ that omits features unsuitable for use within a multithreaded kernel. By modeling the hardware connected to a Mac OS X system and abstracting common functionality for devices in particular categories, the I/O Kit streamlines the process of device-driver development.

This chapter talks about the inherent capabilities of the I/O Kit (and of the drivers developed with it), about the decisions informing its design, and about the I/O Kit when considered as a product. It also offers some caveats and guidelines for those considering developing kernel software such as device drivers.

Contents:

Before You Begin
I/O Kit Features
Design Principles of the I/O Kit
Limitations of the I/O Kit
Language Choice
The Parts of the I/O Kit
Should You Program in the Kernel?

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