title: How can a daemon stay active while using no memory?
body: <p>I come up with this question while using the <code>ps aux</code> command.</p>
  
  <p><img src="https://i.imgur.com/t9hp7J5.png" alt="ps aux"></p>
  
  <p>Here I can see that a few processes are at <em>0% CPU 0% MEM 0 VSZ 0 RSS</em>.</p>
  
  <p>If a daemon is not using any memory, why and how could it be displayed in the first place ? I kind of understand that <em>0% CPU</em> usage mean the process is not currently in use but wouldn't <em>0% MEM</em> mean no process at all ?</p>
  
  <p>I wanted to check if this was somehow systems daemon specific so I made a simple C program with an infinite loop, without any variables.</p>
  
  <pre><code>void main()
  {
          while (1){}
  }
  </code></pre>
  
  <p>This time VSZ and RSS have actual values, while MEM staying at 0%. 
  <img src="https://i.imgur.com/gDZkQeH.png" alt="memory test"></p>
  
  <p>What is happening here ?</p>