Virtual memory and paging: Which functions are typically performed by paging software in a virtual-memory operating system?

Introduction / Context:
Paging underpins virtual memory by mapping virtual addresses used by processes to physical frames in RAM. Understanding paging software clarifies how modern OSes isolate processes, enable memory sharing, and provide each program with a consistent address space view.

Given Data / Assumptions:

• Processes use virtual addresses; the OS and MMU translate to physical addresses.
• The OS manages page tables, faults, and replacement policies.
• Security and isolation depend on correct mapping and permissions.

Concept / Approach:
Paging software is responsible for the access environment (each process’s virtual address space), physical memory management (frame allocation, replacement), and enforcing sharing/protection (read/write/execute permissions, copy-on-write). These functions together enable efficient and safe multitasking.

Step-by-Step Solution:

Verification / Alternative check:
OS textbooks (virtual memory chapters) detail these responsibilities, including page faults, TLB management, and protection bits.

Why Other Options Are Wrong:
Picking any single function understates paging’s comprehensive role. “None” is clearly incorrect.

Common Pitfalls:
Confusing paging with segmentation; assuming paging is only swapping to disk (it is broader—address translation and protection as well).

Final Answer:
All of the above