Reliability, Safety, and Security in Everyday Embedded Systems (Extended Abstract)

Extended Abstract Embedded systems permeate our everyday lives. From automobiles to elevators, kitchen appliances to televisions, and water heaters to cell phones, we increasingly depend upon embedded systems to operate as expected. A few obviously critical embedded application domains, such as aviation, have traditionally benefited from extraordinary care during development to ensure that everything is done correctly. But increasingly, everyday embedded applications are becoming " mission critical, " with little fanfare and perhaps without the full attention to dependability properties that they truly deserve. Consider the following potentially significant failure modes for embedded systems: A cell phone that doesn't work when the owner needs to call for emergency medical attention. A domestic hot water heater that overheats water, causing scalding burns on a child. A thermostat that doesn't turn on heat when needed, causing household water pipes to freeze and burst. A microwave oven that turns on with the door open. An automobile that unintendedly accelerates. Today, hardware interlocks mitigate many of these hazards. But, software is playing a bigger role as both a vulnerability and a mitigation mechanism for critical failures. Because most embedded systems have actuators that influence the environment, and because people count on them to operate as expected, special care must be taken to ensure that they are safe, reliable, and secure. Safety in the context of embedded systems deals with minimizing the frequency of mishaps (especially loss of life, injuries, and damage to property). In many ways this is the most mature of the areas we are discussing, because there are several industry-specific standards that can be followed to create safe systems (e.g., IEC 61508). There are, however, some significant research challenges outstanding in this area, including: • How can we be sure that following a given system development process actually results in the hoped-for level of safety? • How can we make it easy for small, non-specialist teams of domain experts to follow complex, " heavyweight " safety standards and actually get it right? • How can we simplify the representation and specification of safety properties to make it easier to design safe systems? Reliability in embedded systems has been studied for many years, and has to do with ensuring that once an embedded system starts a " mission, " it has a high probability of completing that mission without experiencing a failure. Traditional