title: Can't clear entire screen in 16-bit real mode Assembly
body: <p>I'm trying to clear the screen in my simple 16-bit real mode operating system. Below is the code:</p>
  
  <pre><code>clearScreen:
      pusha
  
      mov ah, 0x7
      mov al, 0
      int 0x10
  
      popa
      ret
  </code></pre>
  
  <p>I read that setting <code>al</code> to 0 and calling the scroll screen interrupt would clean the screen but it only seems to change the colour of the first line to grey.</p>
  
  <p>Thanks to anyone who can explain why this is not working.</p>