The OTP virtual machine takes a lot of memory. It's an interpretter, which means much slower execution, as article and others above pointed - The Erlang VM is s

The OTP virtual machine takes a lot of memory. It's an interpretter, which means much slower execution, as article and others above pointed - The Erlang VM is soft-realtime, it can't guarantee that something would finish in certain amount of micro or milliseconds, or if it does guarantee - it's too much for what they need (just guessing here). But the concepts are very similar - message passing being the way to communicate between modules, rather than shared memory ways. This brings another topic - the Linux vs Minix debate :) - I guess there are right things to be done for the right time, and right target. It's just getting all these things right is the hardest.