How to Choose the Best Embedded RTOS
Your choice of RTOS affects embedded system performance, development time, regulatory compliance, and total cost. The main selection criteria for an RTOS are usually the overhead it imposes on the processor and response time of RTOS functions, such as:
- Interrupt latency: delay between an interrupt coming from an external event and the response to that interrupt.
- Context switch time: time it takes to switch from one task to another, generally the most time-consuming set of operations in a real-time system.
- Memory footprint: amount of physical memory (ROM and RAM) required by the RTOS to store kernel code, runtime libraries, and middleware as well as application processing overhead.
Several More RTOS Selection Criteria Include:
- Features
- IoT development ecosystem
- POSIX compatibility (PDF)
- Embedded security
- Functional safety certification
- Licensing
- Documentation
- Support
Bare Metal vs. Open Source vs. Commercial RTOS
When deciding whether to use a bare metal, open source RTOS, or commercial RTOS, there are several considerations:
- Bare metal systems have applications running directly on hardware with no intermediate software layers. These systems are easier to optimize for performance but require more effort to add features and secure as there is little to no ecosystem support.
- Open source RTOSes are freely available and come with community-driven features and support. They often lack enterprise-level support, unless it is purchased separately.
- Commercial RTOSes are optimized for a range of use cases and are backed by professional engineering and support teams to roll out features and solve issues quickly.