[erlang-questions] Millions of processes?

Matthias Lang <>
Mon Sep 29 08:24:15 CEST 2008

On Sunday, September 28, YourSurrogateGod wrote:
> This is somewhat off-topic, but I didn't know that there is a 64-bit
> erlang VM. How is it different than the 32-bit one? Also, how can I
> find out which one I'm running?

The "64-bit emulator" is "just" the Erlang system compiled on and for
a 64-bit system, e.g. an AMD-64, or a 64-bit Sun system, or...

An important difference is that 'all' pointers are 64 bits wide
instead of 32 bits wide, i.e. a 64 bit system can address (use) more
memory than one compiled for a 32 bit system, which is what the original
poster was talking about. Another effect is that it generally does.

You can see if you're running a 64 bit emulator from the startup message.
Here's what it looks like:

~ >erl
Erlang (BEAM) emulator version 5.6.4 [source] [64-bit] [smp:2] [async-threads:0] [hipe] [kernel-poll:false]

Another way is to look at erlang:system_info(wordsize). It returns 4 on
32 bit systems and 8 on 64-bit systems.


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