‘For reliable systems, we need a different mindset.’
We often say that reliability must be designed in, not tested in. What do we mean?
I recall a debate from early in my career as a young software engineer about the merits of optimizing for the average case behavior versus optimizing for the worst case. The product in question had a lot of serial interfaces. Those arguing for the average case advocated interrupting routines tied to each of the serial ports. That way, if a subset of ports were active, the non-active ports would not use any processing cycles. This, they reasoned, would give optimal performance for a typical workload. My approach was to create one timer interrupt at a specified highest byte rate for the serial ports. My interrupt handler checked all the ports for data. This guaranteed a worst-case throughput of the timer interrupt rate on all ports.
Doug is one of Suntra’s most senior engineers, bringing over 25 years of product development experience to complex design challenges. He architects and implements real-time systems and software while expertly leading client projects. With dozens of medical devices to his credit, Doug has deep expertise in regulatory expectations—he wrote the quality system for one of […]
