OS design principles

0.OS should be as fast as possible.
1.OS should use the least memory, unless it hurts #0.
2.OS should have the most security, unless it hurts #1,#0.
3.OS should have the most compatibility, unless it hurts #2 , #1,#0.
4.OS should have the most features, unless it hurts #3,#2,#1,#0.

Security is more important than speed and memory.