I can think of a few more... Operating Systems. Games. Deterministic soft and hard real-time systems (there's a reason you wouldn't be able to certify a contro

I can think of a few more... Operating Systems. Games. Deterministic soft and hard real-time systems (there's a reason you wouldn't be able to certify a control system for a fighter jet written in Javascript). Scientific stacks. Multi-media (do you think Renderman is written in Ruby?). I'd even argue against using GC'd languages in desktop applications. It's getting to a point where these run-times are gobbling up a few gigs worth of pages from the OS and they still hang or crash when the OS decides to start paging them to disk. Or another process gets priority from the scheduler. The fact is while processor speeds have increased memory hasn't and that's the big bottle-neck on current hardware. Despite popular beliefs I think users do care about performance. They don't notice good performance but as soon as that beachball/whitescreen/whatever comes up and the UI is unresponsive you can bet their face is scrunching up like a walnut. Does that happen only to 1 or 2 users? 10%? We don't measure things like that enough when our happy little GC will take care of it for us. Tuning GCs for workloads is probably as much or more work, in my limited experience, as designing your program from the bottom up around its specific data patterns. You'll get better performance from the latter approach more often than tuning a GC to your workloads after profiling. The wins in that case are incremental (we tuned our JVM after some profiling and shaved off 1.8% from our inner loop!). Where they can be dramatic with the right data structures and careful attention to locality (we saw an 800x reduction in cycles due to cutting unnecessary allocations and a 300% speed increase -- sweet!). Even tuning your allocation strategy can net you bigger gains than trying to structure your code around a JIT. All that being said -- GC's are incredibly useful in many situations. You just have to measure and be thoughtful. Memory is still an issue GC or not.