The erlang process model, since SMP support is more or less, each cpu core runs one OS thread which is running a 'scheduler'. Each scheduler has a list of processes, and determines the order they should get to run in; the currently scheduled process is run in the scheduler's thread, until it has used its quota of cpu (reductions) or it hits some other trigger that causes its execution to be suspended (waiting for a message, sending a message to a busy port, maybe some other cases?). Schedulers have a method to balance their work queues, etc. (Leaving out dirty schedulers, io schedulers, configuration of schedulers etc)
Each erlang process has its own (erlang) heap and stack, and there is no ability within the Erlang language to access memory by address, a process will only access its own memory, or special types of shared memory (such as the shared/large binary heap).
From the OS perspective, it's one process, with one memory space, and several threads.
A realistic Erlang example where you would have 2 Million processes is something like a chat server (1 process per connected user), either via a traditional tcp protocol or a websocket protocol for a browser. In another language, you would likely need to multiplex multiple users onto each thread, in Erlang each user gets their own process and the code ends up being quite straight forward.
Each erlang process has its own (erlang) heap and stack, and there is no ability within the Erlang language to access memory by address, a process will only access its own memory, or special types of shared memory (such as the shared/large binary heap).
From the OS perspective, it's one process, with one memory space, and several threads.
A realistic Erlang example where you would have 2 Million processes is something like a chat server (1 process per connected user), either via a traditional tcp protocol or a websocket protocol for a browser. In another language, you would likely need to multiplex multiple users onto each thread, in Erlang each user gets their own process and the code ends up being quite straight forward.