What makes an embedded system different from the computer on your desk? It’s not just about size; it’s about a completely different philosophy of design, built on three core principles.

• Dedicated to a Single Task An embedded system is a specialist, designed to perform one function repeatedly and reliably throughout its operational life. A pager, for instance, is always a pager and does not gain new features.
• Tightly Constrained These systems must operate within strict limits on design metrics like cost, size, power consumption, and performance. Often, the entire system must be small enough to fit on a single chip and consume minimal power to preserve battery life.
• Reactive and Real-Time Embedded systems must continually sense and react to changes in their environment without any noticeable delay. A car’s cruise control, for example, must constantly monitor speed and react to the brake sensors in real-time to maintain control of the vehicle.

So, how do engineers achieve these impressive characteristics? It all comes down to a simple but elegant structure of physical components, each with a specific job in a chain of command.