Analyze the structure of the personal computer industry using Porter’s Five Forces. Are these dynamics favorable or problematic for Apple?

Apple Computer 2012

1. What, historically, have been Apple’s major competitive advantages?
2. Analyze the structure of the personal computer industry using Porter’s Five Forces.  Are these dynamics favorable or problematic for Apple?
3. How sustainable is Apple’s competitive position in PCs?
4. How do you assess Apple’s competitive position in smartphones?
5. What are Apple’s long-term prospects for the iPad?