On Tue, Mar 12, 2013 at 5:09 PM, Charles Hixson <lists / ruby-forum.com>wrote:

> Does Ruby 2.0 run more than one thread at a time?  The documentation I
> have says that Ruby 1.9 does not.


You're talking about the Global Interpreter Lock or GIL (also known as the
Global VM Lock, or GVL)

The answer is no, Ruby 2.0 does not remove the GIL, and there are not plans
to remove it at this time. Note that this lock does not preclude you from
carrying out I/O-related tasks in parallel. It only limits multicore
operation (i.e. multiple cores running Ruby code)

That said, JRuby, Rubinius, and other Ruby VMs provide true thread-level
parallelism via GIL-free operation and are "multicore-aware"

-- 
Tony Arcieri