Time Controls

Hi.  I'm having some trouble understanding all of the terms for time controls.  I just got a flyer for a tournament and under time controls it says:

G90 D/5

I thought that the D/5 meant like a 5 min game, but the G90 has me confused.  I started to read an overall of "Time Controls" but it started to confuse me more.  If someone could let me know what this particular control is, and maybe even a reference to a better place to look for info, would really appreciate it....!!  THANKS.

GXX means that each side has XX minutes of base time on their clock. D/X means that there is a delay of X seconds before the clock starts counting down (in a normal delay mode).