A computer system supports 32-bit virtual addresses as well as 32-bit physical…

Correct answer: Efficient implementation of multi-user support is no longer possible.

Why this is true:

• Address space isolation: Virtual memory gives each process a private address space so processes cannot accidentally or maliciously access each other’s memory.

• Protection and access control: The MMU enforces access permissions (read/write/execute) per page; without address translation hardware this protection must be implemented in less flexible or less efficient ways.

• Swapping and memory overcommit: Virtual memory allows the OS to map process pages transparently to disk when physical RAM is scarce, enabling many users/processes to share limited physical memory efficiently.

• Convenience features: Techniques like copy-on-write, demand paging, and simple process creation rely on virtual memory mechanisms.

Because these capabilities are central to scalable, efficient multi-user systems, removing virtual memory makes it much harder to provide efficient multi-user support. The other statements are incorrect or misleading for the reasons below:

• The idea that processor cache organization can be made more efficient is not generally true: caches may be simplified in some respects without virtual memory, but overall cache performance depends on many design choices and is not guaranteed to improve.

• Hardware support for memory management is still needed: protection, efficient context switching, and correct interactions with DMA and caching require hardware mechanisms even if full virtual memory is not used.

• CPU scheduling is largely independent of whether virtual memory exists; removing virtual memory does not inherently make scheduling more efficient.

Summary: Virtual memory is not only about extending address space size; it is essential for isolation, protection, and memory-sharing features that enable efficient multi-user systems. Removing it undermines those capabilities.