Elmasri, Levine, and Carrick's "spiral approach" to teaching operating systems develops student understanding of various OS components early on and helps students approach the more difficult aspects of operating systems with confidence. While operating systems have changed dramatically over the years, most OS books use a linear approach that covers each individual OS component in depth, which is difficult for students to follow and requires instructors to constantly put materials in context.
Elmasri, Levine, and Carrick do things differently by following an integrative or "spiral" approach to explaining operating systems. The spiral approach alleviates the need for an instructor to "jump ahead" when explaining processes by helping students "completely" understand a simple, working, functional system as a whole in the very beginning. This is more effective pedagogically, and it inspires students to continue exploring more advanced concepts with confidence.