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Last Updated: June 30, 2025

Understanding Memory Management Unit (MMU) and Translation Lookaside Buffer (TLB)

The Memory Management Unit (MMU) is a critical hardware component in a computer system that handles memory management and address translation. It sits between the CPU and the main memory (RAM) and is responsible for translating virtual addresses (used by software) into physical addresses (used by hardware). The MMU plays a key role in enabling features like virtual memory, memory protection, and paging.

1. What Does the MMU Do?

The Memory Management Unit (MMU) primarily manages primary memory (RAM) and facilitates the translation of logical/virtual addresses into physical addresses. It plays a key role in managing the following:

• Virtual Memory: Ensures processes have their own virtual address space.
• RAM: Controls direct access and allocation.
• Cache Memory (indirectly): While the MMU doesn’t directly manage cache, it works with it by translating addresses used in memory accesses.

Does MMU relate to and manage all memory storage types, or is it specific?

It doesn’t directly manage secondary memory (like HDD or SSD), but it works in conjunction with the operating system to handle paging/swapping between RAM and secondary storage.

So, MMU is specific to primary memory and virtual memory management.

2. Key Functions of the MMU

1-Virtual-to-Physical Address Translation

• Converts virtual addresses (used by programs) into physical addresses (used by the RAM memory hardware) by using a page table, maintained by the operating system, to map virtual pages to physical pages.