Factors to Consider When Choosing an RTOS

November 17th, 2016 by

An RTOS or real-time operating system refers to an operating system with guaranteed capabilities within given time constraints. For instance, an operating system can be designed to make sure that an object is utilized for a robot in the assembly line. If the system runs on a hard real-time operating system, there will be a failure or termination if the object is not used at the specified time. Basically, a real time operating system can be hard or soft. Here are the 3 factors that should be considered when choosing a real time operating system: .


The scheduling algorithm for an RTOS interrupts latency as well as switch times for context, and this defines system determinism and responsiveness. A crucial consideration is the response type that is desired. A hard real-time response may be required if the deadlines are precisely defined. This means failure to meet the deadlines leads to system failure. Soft real-time response may be required if the system is non-deterministic. This means that notifications are not provided regarding completion of every task.

System resources

The system resources available and functionality for task scheduling should be considered when choosing a real-time operating system. For instance, if there are minimum resources in the system, micro kernels can be used. These deliver hard real-time responses and they are common in embedded microprocessors where ROM/RAM capacity is limited. However, they can also be used in large embedded processors. OS’s with full features like WinCE and Linux can also be used. The operating systems provide an environment that is rich in features that are normally supplied with middleware components, GUI’s and drivers. A fully featured operating system is less responsive and it requires more processing power and memory than the micro kernels. These OS’s are mostly used on strong embedded processes with plenty system resources.


Real-time operating systems are either professionally licensed or open-source. Open source RTOS are distributed under modified General Public Licenses (GPL). However, the licenses can have copyright restrictions with little protection. Copyright restrictions are not present in professionally licensed operating systems. They also offer warranties and complete Intellectual Property (IP) infringement indemnification. Additionally, support provision and product quality are the responsibilities of one’s own company.

For every real-time operating system – product quality and support are very important. That’s why it is highly advisable that you get a professionally licensed real-time operating system. For applications that need internal design standards, there is pre-certification as well as certifiable RTOS.


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