title: Is there a fundamental flaw in operating system structure?
body: <p>At some point I read that operating systems were meant to be created in a certain way (i.e. 'microkernel') to be resistant to fault but are made in another way (i.e. 'monolithic') for practical purposes such as speed. Whilst this is <strong>not</strong> the question, it does bring up the question:</p>
  
  <p><strong>Have any fundamental tradeoffs been made in computer architecture that have reduced security from the earlier theoretical systems?</strong></p>
  
  <p>I'm looking for answers that are accepted in the field of computer science, not opinions on current implementations. For example programs could run faster if they were all built on custom hardware, this is known, but this is impractical which is why we have general computers.</p>