There was also ObjectiveFS discussed on HN a few days ago, also closed source: <a href="https:&#x2F;&#x2F;news.ycombinator.com&#x2F;item?id=10117506" rel="nofollow">https:&#x2F;&#x2F;news.ycombinator.com&#x2F;item?id=10117506</a><p>Main difference appears to be that it supports concurrent mounts, while S3QL can be mounted by one client at a time.