[rdtsc]

Sure. Individual aspects of Erlang/OTP are all present in other systems. OS processes, queuing backends, light weight co-routines, Java has some code reloading too.

But it makes a difference if it is in one language/framework and built-in. It makes tracing/debugging/developing easier.

Like with Python, yeah can use a queuing subsystems and submit jobs. But that is another service to configure and manage. Can use multiprocessing (and I've done that), but can't launch 1M of sub-processes. Which now changes how you develop. It has a green-thread co-routine support via greenlet (eventlet & gevent) but those share memory and if you do any CPU intensive work will block each other and will also share the heap.

[vvanders]

I'd say it's a stretch that Java has code reloading. Sure you can reload the bytecode, but unless you're marshaling the data to the new version like Erlang does you're just introducing more errors than fixing things.