title: Segment Descriptor vs Gate descriptors
body: <blockquote>
    <p>Can anyone please explain me precise difference between Segment
    descriptor and Gate descriptor? I am trying to go through Intel
    manuals but not able to figure out why exactly we need Gate
    descriptor? What facility or support mechanism is it providing other than segment descriptors? We can do the priviledge level check when we are trying to
    access the segment descriptors also right? Moreover I guess Linux and
    Windows dont use the Call gate descriptor. Or is it kind of one more
    layer of protection before we get access to segment descriptor? I want to know the precise difference and the need of gate descriptors.</p>
  </blockquote>