title: Repository vs database vs filesystem
body: <p>What makes repository different from database, filesystem or any other kind of storage?
  How can I exactly tell that this or that is repository judging by some set of features that it has or does not have? </p>
  
  <p>When I say 'repository', first of all I mean version control. But there are other examples of repositories, such as digital libraries, for instance. There might be other examples, of course, but all of them would assume that repository is 'the place where you can store something'. But it's not really clear what exact differences does it have that allows to distinct it from other 'places where you can store something'.</p>