title: Understanding /boot/config file
body: <p>In <code>/boot/config-$kernel_version</code> I see things like:</p>
  
  <pre><code>CONFIG_X86_TSC=y
  CONFIG_CAN_TSCAN1=m
  </code></pre>
  
  <p>Now, I thought that <code>y</code> stood for <code>yes</code>, which means the option is set.
  But how about <code>m</code>? </p>