I. INTRODUCTION
Embedded systems are part of our lives. We use them in any activity we perform during the day: from the clock we use to wake up in the morning to the TV set we use to watch the news in the evening. From the washing machine we use to clean our clothes to the microwave oven we use in our kitchen. From the car we use for transportation to the PDA system we use. From medical devices used in hospitals to industrial devices used in manufactures. During a normal day we use several devices that are made from embedded systems and we use that without knowing the technology behind those devices.