An Overview of Computing Systems
William Hohl · 2009
Most users of cellular telephones don’t stop to consider the enormous amount of effort that has gone into designing an otherwise mundane object. Lurking beneath the display, below the user’s background picture of his little boy holding the balloon, lies a board containing circuits and wires, algorithms that took decades to re ne and implement, and software to make it all work seamlessly together. What exactly is happening in those circuits? How do such things actually work? Consider a ctitious device (although probably not too far off) such as a handheld tablet that displays live television, provides satellite navigation, makes phone calls, acts as a personal computer, and contains just about every interface known to man (e.g., USB, Wi-Fi, Bluetooth, and Ethernet), as shown in Figure 1.1.