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Real men program in C

August 01, 2009

Michael.Barr-August 01, 2009

Turning our attention back to C, give Figure 1 a new look with an eye toward the dominance of that language throughout the 13 years of survey data. C was the most used language for embedded software development in the 1997 survey and in the 2009 survey and in every year in between. C has dominated when multiple languages could be chosen (averaging 81%) as clearly as when only the one most-used language could be chosen (averaging 57%).

Remarkably, C appears to have spent the last five years stealing share from assembly as well as from C++. This recent C vs. C++ data defies the expected movement toward ever higher-level languages. C++ is clearly a part of many embedded software projects--and the primary language for about 27% of those coded in the last five years. But my read on the entire 13-year data set is that use of C++ increased rapidly in the late 1990s, peaked in 2001, and has been stable to slightly declining since.3

The bottom line is that embedded programmers aren't going to stop using C anytime soon. There are several reasons for this. First, C compilers are available for the vast majority of 8-, 16-, and 32-bit CPUs. Second, C offers just the right mix of low-level and high-level language features for programming at the processor and driver level. Until the use of C starts to turn down in future such surveys, C programming skills will remain important.

Ten billion and counting
Of course, C will not survive as an important programming language if it is widely used by a shrinking subset of programmers. For C to remain important, the number of embedded software developers must not shrink. For better or worse, I believe the opposite is happening. Around 98% of the new CPUs produced each year are embedded. And the number of new CPUs per year is on a long-term upward trend.

Figure 2 shows the rise in the number of new CPUs per year next to the Nasdaq Composite stock index. As anyone can see, the number of new CPUs per year more than doubled in the decade shown. By comparison, the Nasdaq index was down in the same interval. There is a palpable disconnect between the growth in numbers of embedded computers and the prices of technology stocks generally.

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Based on this data and various other observations over the past 15 years, I conclude that (a) the practice of embedding software into products is on a fast growth curve, and (b) the number of people writing embedded software is growing too. It is important to note that 8-bit processor sales remain a large and growing segment and that these tend to require only one- to two-person programming teams. As processors become cheaper, new applications emerge.

The embedded software education gap
At the same time that C becomes increasingly important to the world, fewer learn how to use that language in school. This is part of a larger "education gap" affecting all organizations that make embedded systems. American institutions of higher learning largely fail to teach the practical skills necessary to design and implement reliable embedded software. From the importance of C's volatile keyword to reentrancy to task prioritization within real-time operating systems to state machine implementation, the trustworthy development processes and firmware architectures for embedded software must be learned on the job.

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