> There are Java and Oberon implementations for single digit MB, like Cortex-M4.
So? Just because you can use a language on a given system doesn't mean that you should use it in any serious context.
A GC typically makes memory usage and execution latency non-deterministic, or at the least very hard to analyze. If your washing machine software OOMs whenever the GC didn't run between two button pushes, you'll have a great Heisenbug.
"PERC Ultra offered Lockheed Martin the responsiveness it needed to meet its most demanding timing requirements. In addition to real-time threading and deterministic garbage collection, PERC Ultra provided the instrumentation and VM management tools necessary to support the mission-critical real-time requirements of the Aegis Weapon System."
"The Lockheed Martin-developed Aegis Weapon System is the sea-based element of the U.S. Ballistic Missile Defense System. The Aegis Weapon System is a radar and missile system integrated with its own command and control system, capable of simultaneous operation defending against advanced air, surface, and subsurface threats."
Is this where we bring in the anecdote about the missile flight control system which never freed any memory, because the minumum time to OOM was less than the maximum flight time of the missile?
> A GC typically makes memory usage and execution latency non-deterministic, or at the least very hard to analyze.
You could say same about malloc and free. Not deterministic at all either. Memory fragmentation is a huge issue as well, and can bring down the whole system.
Typical GC (not all flavors) has a huge advantage on microcontrollers: you gain ability to compact heap. No more fragmentation.
That said, mostly I try not to dynamically allocate anything in firmware or kernel drivers. Whenever possible. Sometimes I write my own specialized allocators. For example a simple wait free allocator fast and rugged enough to call from an interrupt service routine.
So? Just because you can use a language on a given system doesn't mean that you should use it in any serious context.
A GC typically makes memory usage and execution latency non-deterministic, or at the least very hard to analyze. If your washing machine software OOMs whenever the GC didn't run between two button pushes, you'll have a great Heisenbug.