If I say that Open Source mobile OS are ruling the world of mobile devices, it won’t be an exaggeration. Though many don’t consider, Android is still an open source project. This is another thing that the devices you use come with a bundle of proprietary software along with Android and hence many people don’t consider it open source.So what are the alternatives to Android? iOS? Windows? May be but I am talking about open source alternatives to Android. Not one, not two. I am going to list five open source Linux based mobile OS that you may use even when I write this article.