Which of the following statements is INCORRECT about memory protection?

Concept

A base-and-limit (relocation + limit) scheme protects memory by bounding every process to a contiguous region. The relocation (base) register holds the SMALLEST physical address allocated to the process, and the limit register holds the RANGE (size) of the valid logical addresses. The MMU forms a physical address as base + logical address, and admits the access only while the logical address is strictly less than the limit; otherwise it traps.

Applying it to each statement

• "Used to protect the OS from user processes" — true: bounding each process to its own region is exactly what memory protection does.

• "Provided by a relocation register together with a limit register" — true: this base+limit pair is the standard hardware mechanism.

• "The relocation register contains the largest physical address" — FALSE: the relocation register holds the smallest (base) physical address, not the largest. This is the incorrect statement, hence the answer.

• "The limit register contains the range of the logical addresses" — true: the limit register stores the size/range of valid logical addresses (each logical address must be < limit).

Cross-check

Physical address = base + logical address. If the relocation register held the LARGEST physical address, adding a logical offset would push every access beyond the process's own region, breaking the translation. So the register that holds the range/upper bound is the limit register, and the relocation register can only be the smallest (base) address — confirming the 'largest physical address' claim is the wrong one.