Why this page matters
This page explains how FAQ fits into the wider ZeroKernel execution model, what problem it is meant to solve, and what trade-off you are actually accepting when you use it in production firmware. The goal is not to treat FAQ as an isolated API call, but to understand where it sits inside bounded scheduling, queue discipline, fault visibility, and profile selection.
Read this topic as an operational contract. Start from the smallest working path, wire it into a lean profile first, and only expand into richer routing, diagnostics, or transport state after you can prove that the timing outcome is still worth the extra flash and RAM. That mindset is what keeps ZeroKernel useful on small boards instead of turning it into another bloated abstraction.
The safest pattern is always the same: define the runtime boundary, keep the hot path short, measure the effect with compare scripts, and only then scale complexity. The examples below are not filler; they show the smallest repeatable patterns you can lift into real firmware when you need clean integration instead of ad-hoc loops.
Three practical patterns
Use this when you need a credible regression pass before publishing numbers or changing docs.
bash scripts/run_desktop_tests.sh
bash scripts/run_desktop_benchmark.sh --enforce-performance
bash scripts/run_resource_matrix.sh --enforce-budget
Run a focused hardware compare instead of guessing whether a change helped or hurt.
bash scripts/run_esp32_modules_compare.sh /dev/ttyUSB1
bash scripts/run_esp32_real_project_demo.sh /dev/ttyUSB1
Lock the build into the intended profile before treating a benchmark or compare as authoritative.
-DZEROKERNEL_PROFILE_LEAN_NET
-DZEROKERNEL_ENABLE_DIAGNOSTICS=0
-DZEROKERNEL_ENABLE_LEGACY_LABEL_API=0
What to verify while you use it
- Validate timing before you validate aesthetics. A cleaner API is not a win if fast misses rise.
- Prefer the smallest profile that still matches the workload, then add optional modules only when the measured payoff is obvious.
- Keep callbacks and transport steps bounded so watchdog, panic flow, and queue limits remain meaningful.
Common mistakes that make results misleading
- Do not copy a demo pattern into production firmware without measuring it on the real board and real build profile you plan to ship.
- Do not read success counters without reading queue depth, timing, and workload label next to them.
- Do not enable heavier diagnostics and compatibility flags in a lean target just because the defaults looked convenient.
Recommended working sequence
Boot the runtime, register the minimum useful task set, and prove that the baseline timing is clean before adding optional layers.
Introduce routing, diagnostics, or transport one layer at a time so the cost and payoff remain obvious.
Update docs, charts, or public claims only after the same workload survives the same validation path more than once.
Does ZeroKernel replace FreeRTOS?
No. ZeroKernel is a bounded cooperative runtime for firmware that does not need a full preemptive RTOS but still needs structure, supervision, and reproducibility.
Can a blocking task still hurt the system?
Yes. Cooperative scheduling cannot preempt a blocking call. ZeroKernel helps by making the problem visible and by encouraging bounded patterns, but the application still has to keep tasks short.
Why do some modules stay BETA?
Network behavior is more variable than core scheduling. Right now, the strongest result is on ESP32, where the network helpers are stable enough for production-style evaluation. The global BETA label remains because ESP8266 still needs more live-network hardening before the same claim is fair across boards.
Why can memory usage go up?
Because better determinism, queue discipline, and recoverability cost some state. The goal is not zero cost. The goal is a bounded, defensible cost with a measurable payoff.