In this chapter, we began by looking into the different timing features provided in the eCos system. This gave us an understanding of how counters, clocks, and timers are used in our application. We also explored the assert and tracing functionality and how we can use these features during the application debug cycle. We got a basic understanding of the libraries (C and math) included with eCos. Finally, we looked at the I/O Control System and how to use it with the existing device drivers provided with eCos.