Archive for February, 2008

More Bad RTOS Information

Thursday, February 28th, 2008 Michael Barr

The Internet (and magazines and conferences) are filled with bad information about when to choose an RTOS. In short, the world wants to sell you an RTOS, even when you don’t need one or the use of one would overly complicate your software design.

Here are two generalizations from a recent whitepaper:

Operating systems make programming more efficient and better structured, and their use is now frequently justified even in embedded solutions that are relatively small.


A clear benefit of using an RTOS is that it reduces time to market, because it simplifies development.

At best, this is misguided advice.

Here’s the straight scoop. An RTOS may either “make programming more efficient and better structured” or less efficient and poorly structured; it depends on the nature of the requirements. In many cases, a design composed entirely of state machines is easier to code and works more reliably than one using an RTOS. In other cases, particularly closed-loop control systems, a simple main+ISR approach will work even better.

Embedded Systems History

Thursday, February 28th, 2008 Michael Barr

The editors of Embedded Systems Design recently put together an interesting historical timeline of the embedded systems industry. To learn some history, take a stroll over to

Kill the Patent Office

Wednesday, February 13th, 2008 Michael Barr

I’m not sure what to make of all the criticism of and suggested improvement to the U.S. patent system. However, I found this article thought-provoking:

Embedded C Quiz Results

Monday, February 11th, 2008 Michael Barr

When we redesigned the website late last year, we thought it’d be fun to challenge our more than 20,000 monthly visitors (mostly embedded software engineers) to a skills test. So we developed a ten question multiple-choice quiz ( And it has been a popular feature of the new site, with a couple hundred participants just in the first two months.

And now the results are starting to come in. We analyzed the early results a couple of ways and discovered something worth talking about: Quiz takers from India did about the same as quiz takers in the U.S. But the rest of the world lagged behind these two groups quite a bit.

There are ten questions in our quiz, and we consider a passing score to be 8 out of 10. A handful of quiz takers have scored 100%, but most score in the 30-90% range, with an overall average at 60.4%. (A little scary, huh?)

Statisically speaking, there were three significant groups of quiz takers by geography. The average score of those taking the quiz from the United States was just shy of 64%. The average for India was not far behind at about 61.2%. However, the rest of the world scored an average of just 55.9%.

What does this say about the state of the profession of embedded software development? Offshoring? The quiz itself?

Breathalizer Source Code to Get a Day in Court

Thursday, February 7th, 2008 Michael Barr

Here’s an interesting news story at the intersection of embedded systems and due process:

How many potential bugs might a knowledgable expert witness spot in your code? Are the comments in your source accurate and clean enough for a judge or jury to read?