12.11 Exploring Specific PC Peripheral Devices

This chapter has so far introduced I/O in a very general sense, without spending too much time discussing the particular peripheral devices present in a typical PC. It some respects, it's dangerous to discuss real devices on modern PCs because the traditional ('legacy') devices that are easy to understand are slowly disappearing from PC designs. As manufacturers introduce new PCs, they are removing many of the legacy peripherals like parallel and serial ports that are easy to program, and they are replacing these devices with complex peripherals like USB and FireWire. Although a detailed discussion on programming these newer peripheral devices is beyond the scope of this book, you need to understand their behavior in order to write great code that accesses these devices.

Because of the nature of the peripheral devices appearing in the rest of this chapter, the information presented applies only to IBM-compatible PCs. There simply isn't enough space in this book to cover how particular I/O devices behave on different systems. Other systems support similar I/O devices, but their hardware interfaces may be different from what's presented here. Nevertheless, the general principles still apply.