Verifying embedded software functionality: Why it's necessary

Abhik Roychoudhury, National University of Singapore
EETimes (8/5/2012 1:58 PM EDT)

Embedded software and systems have come to dominate the way we interact with computers and computation in our everyday lives. Computers are no longer isolated entities sitting on our desks. Instead, they are nicely woven and integrated into our everyday lives via the gadgets we directly or indirectly use—mobile phones, washing machines, microwaves, automotive control, and flight control.

Indeed, embedded systems are so pervasive, that they perform the bulk of the computation today— putting forward “embedded computing” as a new paradigm to study. In this series, we focus on validation of embedded software and systems, for developing embedded systems with reliable functionality and timing behavior.

Not all embedded systems are safety-critical. One one hand, there are the safety critical embedded systems such as automobiles, transportation (train) control, flight control, nuclear power plants, and medical devices. On the other hand, there are the more vanilla, or less safety-critical, embedded systems such as mobile phones, HDTV, controllers for household devices (such as washing machines, microwaves, and air conditioners), smart shirts, and so on.

Irrespective of whether an embedded system is safety-critical or not, the need for integrating validation into every stage of the design flow is clearly paramount. Of course, for safety-critical embedded systems, there is need for more stringent validation—so much so that formal analysis methods, which give mathematical guarantees about functionality/timing properties of the system, may be called for at least in certain stages of the design.

Our focus in this series is on what has been learned about software validation methods, and how they can be woven into the embedded system design process. Before proceeding further, let us intuitively explain some common terminologies that arise in validation—testing, simulation, verification, and performance analysis.

Testing refers to checking that a system behaves as expected for a given input. Here the system being checked can be the actual system that will be executed. However, note that it is only being checked for a given input, and not all inputs. Simulation refers to running a system for a given input. However, simulation differs from actual system execution in one (or both) of the following ways.

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