Steady-state cardio is what you described. It's not as effective as HIIT given the same amount of time.
http://www.hiitsource.com/
http://www.askmen.com/sports/bodybui...tness_tip.html
For beginners, I'd recommend an interval structure like this:
30 seconds as hard and fast as you can go, 1.5 minutes of active recovery (faster than a warmup, but not nearly as fast as the previous 30 seconds)
20 minutes of that, and you should be exhausted.