✅ Lower overhead in terms of latency / non-deterministic timers ✅ No scheduling, interrupt or priority handling complexity ✅ Direct access to hardware ✅ Lack of standard interface (APIs) means open to customisation ✅ Predictable behaviour (no tasks/schedule conflicts / eviction etc) A bare-metal OS is “better” than an RTOS for applications where simplicity, minimal overhead, and direct hardware control are critical, such as in resource-constrained or ultra-low-latency systems. However, for complex systems requiring multitasking, scalability, or standardized abstractions, an RTOS is typically more suitable unless there is dedicated micro controller for every peripheral 😅
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Here's an uncomfortable truth: Most RTOS implementations in embedded systems are nothing but unnecessary overhead that makes developers feel sophisticated while actually introducing more problems than they solve. We've all been there, facing a complex embedded project and immediately reaching for that "industry-standard" RTOS solution. But let's be honest: in 80% of applications, an RTOS is like using a sledgehammer to crack a nut. The context switching overhead alone can consume precious CPU cycles that your resource-constrained device can't afford to spare. And don't get me started on priority inversion issues that turn your "deterministic" system into a timing lottery. I've spent countless hours debugging mysterious timing issues only to discover they were caused by the RTOS itself, nondeterministic interrupt latency, hidden system calls, and the inevitable memory fragmentation when dynamic task creation is involved. What we really need is a return to bare-metal programming with well-structured state machines and interrupt-driven design. It's not "old school", it's engineering discipline. When your microcontroller has 32KB of flash and 4KB of RAM, every byte counts, and every unnecessary abstraction is a liability. The next time you're tempted to drop an RTOS into your project, ask yourself: Do I really need it, or am I just avoiding the hard work of designing a proper architecture? 🔥 What's the most ridiculous RTOS-induced nightmare you've ever debugged? Share your war stories below, bonus points for priority inversion horror stories! #EmbeddedSystems #RTOS #BareMetal #Firmware #EmbeddedC #RealTimeSystems #LowLevelProgramming #TechTruth #EmbeddedEngineering
Embedded Software Engineer
1moHere's how to know if you really need an RTOS. The core characteristic of an RTOS is the priority-based preemptive context switch. Bare Metal systems may not be "real-time": in a Bare Metal system (i.e. main loop of tasks) if there is a high priority task with a deadline AND at least one very long low priority task, then it is possible that when the high priority task's data arrives, the very long low priority task had just begun executing. After the high priority interrupt handler executes and saves the data, the low priority task will resume execution. Now the high priority task must wait for the low priority task to run to completion. With an RTOS, after the high priority interrupt handler saves the data, it can initiate a preemptive context switch and preempt the low priority task allowing the high priority task to immediately begin processing its input (hence "real-time"). HOWEVER BEWARE! Every RTOS today can disable an application's interrupts for a time that grows with the number of tasks which can cause loss of incoming data. ONLY real RTOS (patents granted) solves this previously unidentified extensibility problem. https://drive.google.com/drive/folders/1WoB_RBqRs-KPMK4-zTFdxsNhQ3qCi67C?usp=drive_link