23. Advantages of Flat Memory Model

• 32-bit Protected Mode supports much larger data structures than Real mode.

• Because code, data, and stack reside in the same segment, each segment register can hold the same value that never needs to change.

• Rather than using a formula (such as CS:IP) to determine the physical address, protected mode processors use a look up table.

• Segment registers simply point to OS data structures that contain the information needed to access a location.

• Protected mode uses privilege levels to maintain system integrity and security.

• Programs cannot access data or code that is in a higher privilege level.

  • (Segment value exchanges at the same privilege level are allowed.)