Speaker: Mindy Preston reject the default reality^W abstractions and substitute your own. Traditional models of application development involve talking to an underlying operating system through abstractions of its choosing. These abstractions may or may not be a good fit for your language or application, but you have no choice but to use them - you can only layer more abstractions on top of them, to try to lessen the pain of a bad match. Library operating systems let you write applications that use better abstractions in your own language - either someone else's abstractions, or your own.