I have often talked about the process that might be applied to the selection of an embedded operating system and I hope that I can provide some guidance. However, developers tend to stick with a specific OS [or, at least, with a particular OS vendor] – recent research suggested that only about 20% of developers anticipated a change of OS for their next project.

I started thinking about why there is this apparently high degree of loyalty …

I do not think that there is a single, simple reason why embedded software engineers choose to use the same OS time and again. One motivation is that embedded guys have a pragmatic conservatism: “if it ain’t broke, don’t fix it”. Although that attitude is quite reasonable, I think that we can identify two specific reasons not to change OS:

• Vendor satisfaction. If the level of support and quality of documentation is very good or excellent, that is definitely a reason to stick with a particular OS vendor [as it is with almost any product].
• Skills and IP lock-in. The technical characteristics of a given OS permeate the application code and the skill set of the team. This has primarily two manifestations:

1) Drivers and middleware are often very specific to a specific OS. Moving to a new OS implies the acquisition of new skills and rewriting of a lot of code.

2) The application program interface [API] ties the application code to the OS and also represents part of the team’s skill set. It is true that many RTOS products have a proprietary API. Moving to another OS would require changes to the application code. Alternatively, many developers us an OS abstraction layer to protect themselves from such a change – only the layer needs to be modified to accommodate a change in OS. Another approach is to embrace a standard and the common API standard is POSIX. Although this is the native API for Linux, it is also supported by many RTOS products and its use provides a degree of code portability.

If you are sticking with a specific OS for other reasons, I would be interested to hear about your motivations and experiences.

Read more from Colin about embedded software on SciTech Connect

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About the Author

Colin Walls (@Colin_Walls) is an embedded software technologist at Mentor Graphics (@mentor_graphics), the leading EDA software company.

You can read more about Colin and his work on embedded systems at The Colin Walls Blog at Mentor Graphics here. Connect with Colin online here: