title: what is meant by disabling interrupts?
body: <p>When entering an inteerupt handler, we first "disable interrupts" on that cpu(using something like the cli instruction on x86). During the time that interrupts are disabled, assume say the user pressed the letter 'a' on the keyboard that would usually cause an interrupt. But since interrupts are disabled, does that mean that:</p>
  
  <ol>
  <li>the interrupt handler for 'a' would never be invoked, since interrupts are disabled in the critical section or </li>
  <li>the interrupt will be handled by the os but delayed, until interrupts are enabled again.
  Specifically, will the user need to press 'a' again, if the first time he pressed 'a' was at a time when interrupts were disabled ?</li>
  </ol>