DOS

DOS (Desktop Operating System) is an operating system developed by Microsoft. It is often regarded by the experienced computer users among the Tau'ri as a inadequate operating system with very few uses. Whilst aboard a Wraith ship, Rodney McKay accesed the Wraith computers and claimed that the operating system is a "mess", then saying "Thank goodness I remember DOS", inferring that he dislikes DOS and that DOS is even worse that the "mess" that is the Wrath Operating system. Ronon does not react, indicating that he is ignorant to the topic. Source: No Man's Land (episode)