Scalability: the key to product line success
An important requirement for an RTOS such as VxWorks is scalability. What this really means is being usable in many different types of devices, from small memory constrained, low power devices (possibly battery powered, hand held, mobile) to large scale systems, multiple nodes networked together, possibly using multicore in a multi-OS environment. Scaling down is equally important as scaling up. As my colleague Felix Baum had recently posted, flexibility is also critically important part of the equation, an RTOS must be configurable as needed by the developer and run on the hardware platforms they choose, and make the most of the hardware capabilities.
Why not just buy a specific RTOS for each project? This isn't really a viable option anymore. Our customers are looking for a tools and run-time platform they can rely on for a product line rather than an individual product. In the end this turns out the be the best solution both in terms of costs but also in reducing risk and meeting difficult time-to-market targets. A common platform means reuse of code, expertise, tools and most importantly, "one neck to wring", one vendor and one point of contact to solve your problems.