Colin Walls has over thirty years experience in the electronics industry, largely dedicated to embedded software. A frequent presenter at conferences and seminars and author of numerous technical articles and two books on embedded software, Colin is an embedded software technologist with Mentor … More »
December 16th, 2013 by Colin Walls
Today I am going to tell you a tale. It is a true story of events that happened long, long ago in a land far, far away. We are always told that we should learn from our experience [or from our mistakes – it depends whether you do “glass half full” or “glass half empty”]. Hopefully, there are less painful lessons to be learned from the experience of others.
Once upon a time …
There was a young engineer, who was working on software for some fairly simple, 8-bit embedded systems. Although the term “embedded” had not yet been coined. The code was written in assembly language, but it needed to be modular, scalable and maintainable. Having worked on real time computer systems, he concluded that he needed a real time, multi-tasking kernel. Having no idea of any alternative option, he was very pleased to have the opportunity to design and write a kernel. The result of a couple of weeks work was a kernel that was pre-emptive and time-sliced with a background task. It worked well for the required application and the project was completed on time.
The next project came along and the hero of our story saw another opportunity to make use of his kernel. So, he spenta couple days enhancing it to incorporate some new ideas he had had from his experiences in the previous project. Then he used it as the basis for the new application. Once again, the project was completed successfully and on time.
The young engineer was feeling very pleased with himself and, when the third project came along, did not hesitate and used his kernel again. Just like the previous occasion, he invested a little time to improve the kernel based upon his experiences. And, yet again, he was very successful.