What is the role of the Translation Lookaside Buffer (TLB) in memory management?

• A. Stores CPU instructions
• B. Holds I/O device addresses
• C. Cache page table translations to speed up virtual address translation; stores protection bits
• D. Manages disk cache

Answer: (C)

The Translation Lookaside Buffer is a small, fast cache inside the memory management unit that stores recent virtual-to-physical address translations. By keeping these translations handy, the system can convert a virtual address to a physical address in one quick step, without repeatedly walking the page table in memory. Each TLB entry maps a virtual page to a physical frame and includes protection bits (such as present, read/write, and user/supervisor) so the hardware can enforce access rules immediately. If a translation isn’t in the TLB (a miss), the hardware or OS performs a page-table walk to fetch it from memory, updates the TLB, and then completes the access. This role is distinct from storing CPU instructions, I/O device addresses, or managing disk cache, which are handled by other mechanisms.