title: Operating System - paging
body: <p>I read a book about paging (memory-management schemes).</p>
  
  <p>As I understand, each virtual memory is convert to physical memory.</p>
  
  <p>But I don't understand two really basic things: </p>
  
  <ol>
  <li><p>If we have process A and process B, how can we sure that it doesn't convert their linear address to the same physical address?</p></li>
  <li><p>How can we sure that the page, which is now in the physical memory, doesn't belong to two processes?</p></li>
  </ol>