1. In a Multics system, process P1, running in ring 5 , tries to read a segment with an access bracket of (2,4). Can this read access be granted to P ?NIf another process P2, running in ring 1 , tries to read the same segment, with an access bracket of (2,4), can this read access be granted to P2 ?  What if P2 tries to write to the same segment, can this read access be granted to P1 ?
2. A main objective of multilevel security systems is to prevent information leakage from a high-level security process to a low-level security process. State the main two properties of such systems.
3. Unix systems follow a discretionary access control (DAC) approach. Give one example to show that Unix is DAC system. d) Explain the main services the Windows active directory provide.