Is GLaDOs a human

no she is a robot with lots of eyeballs she is often sarcastic and she sings the

song still alive (you have to listen to that song it is a catchy song (the last still

alive words at the end is the best part) oh and she promises cake at the end

but she never gives it to you.

However, it is later revealed that GLaDOS,or at least part of her, was Cave Johnson's secretary at Aperture Science, named Caroline, who was uploaded to the main computer.