Nobody understands the GIL Published on June 12, 2013 by Jesse Storimer Throughout most of my time in the Ruby community, MRI's infamous GIL has been an elusive creature for me. This is a story about thread safety, and finally catching that elusive creature to get a good look at it. The first time I heard mention of the GIL, it had nothing to do with how it worked, what it did, or why it existed.