CS graduate admissions for masters level
Most schools are unknown schools; there are just too many for the admissions committee members to have an idea of the quality of all of them.

So the standard approach is to de-emphasize the GPA and make the decision based more strongly upon the other parts of the application.  If the GPA would be troubling if it were from a good school, then it's still troubling; otherwise, it's more of a threshold ("Well, that's good enough--let's look at the rest of the application.").

(This is generic advice for all academic fields; there's nothing special about CS in this regard.)