Thank you for your comment.
You did a good breakdown of Ruby interpreters. Well, Matz Ruby Interpreter (MRI) Ruby is commonly used and has a GIL. It was the one I discussing. Moreover, a short read obviously won't be able to store the particulars of interpreters, and the article will become academic heavy. To quote myself:
"The particulars of compilers and interpreters are heavily academic and therefore beyond the scope of this article."
However, I am afraid, that your definition of the GIL is faulty. In fact, the GIL destroys performance by baning Parallel Computing or (Multi-threading). I am writing another story about Python where I discuss the GIL in detail. It'll be ready soon.