Browse Definitions :
Definition

memory management unit (MMU)

What is a memory management unit (MMU)?

A memory management unit (MMU) is a computer hardware component that handles all memory and caching operations associated with the processor. In other words, the MMU is responsible for all aspects of memory management. It's usually integrated into the processor, although, in some systems, it occupies a separate integrated circuit (IC).

Effective memory management requires systems administrators to consistently monitor memory use and performance. Tools to help with this process are included in a computer OS and are available for third-party vendors.

What does an MMU do?

The work of the MMU falls into three major categories:

  • Hardware memory management oversees and regulates the processor's use of random access memory and cache memory.
  • OS memory management ensures adequate memory resources are available for the objects and data structures of each running program.
  • Application memory management allocates each individual program's required memory, then recycles freed-up memory space when the operation concludes.
Chart comparing RAM and cache
There are important differences between RAM and cache.

How does the MMU work?

Next to the central processing unit (CPU), memory is the most important part of a computer. It's where the work gets done and where instructions and other computing functions are performed. Memory ensures a computer's utilities work correctly and applications and input/output functions are performed.

An MMU is an essential part of memory subsystems, keeping all memory-related functions operating efficiently. Memory management helps with the following functions:

  • Memory distribution. The MMU moves memory resources to where they can best meet system requirements, typically before and after systems processes are executed.
  • Monitoring. It tracks all memory resources.
  • Efficiency. It conserves main memory and other memory resources.
  • System integrity. It reduces the likelihood of memory fragmentation and poor memory allocation.
  • Data integrity. It ensures data integrity is maintained.
  • Data risk. It minimizes the risk of data corruption.
  • Cost control. It keeps memory-related costs down.

Physical vs. logical memory management

The main differences between logical and physical memory are the following:

  • Logical memory. Logical memory addresses -- also called virtual address space-- are created by the CPU and execute many different functions. Logical memory is also called virtual memory because its size can be dynamically changed based on user processing requirements.
  • Physical memory. In contrast, the MMU computes physical addresses. They're then loaded into the memory address register of the memory subsystem, which is also called physical memory. When physical addresses contain logical addresses, they're called the physical address space. In contrast to logical addresses, physical addresses don't change.

Best practices for memory management

System administrators must regularly monitor memory system performance metrics, such as the following:

  • available memory,
  • memory use,
  • paging activity and
  • fragmentation.

The key to effective memory management and memory protection is having the right tools, such as those provided by the OS and third-party memory management applications. It's also important to respond to alarms based on problems with memory functions and blocks of memory, and to perform proactive maintenance activities to ensure memory resources are optimized.

Learn about memory management techniques that will improve system performance.

This was last updated in September 2022

Continue Reading About memory management unit (MMU)

Networking
  • Telnet

    Telnet is a network protocol used to virtually access a computer and provide a two-way, collaborative and text-based ...

  • big-endian and little-endian

    The term endianness describes the order in which computer memory stores a sequence of bytes.

  • Address Resolution Protocol (ARP)

    Address Resolution Protocol (ARP) is a protocol that maps dynamic IP addresses to permanent physical machine addresses in a local...

Security
  • Mitre ATT&CK framework

    The Mitre ATT&CK (pronounced miter attack) framework is a free, globally accessible knowledge base that describes the latest ...

  • timing attack

    A timing attack is a type of side-channel attack that exploits the amount of time a computer process runs to gain knowledge about...

  • privileged identity management (PIM)

    Privileged identity management (PIM) is the monitoring and protection of superuser accounts that hold expanded access to an ...

CIO
HRSoftware
  • employee resource group (ERG)

    An employee resource group is a workplace club or more formally realized affinity group organized around a shared interest or ...

  • employee training and development

    Employee training and development is a set of activities and programs designed to enhance the knowledge, skills and abilities of ...

  • employee sentiment analysis

    Employee sentiment analysis is the use of natural language processing and other AI techniques to automatically analyze employee ...

Customer Experience
  • customer profiling

    Customer profiling is the detailed and systematic process of constructing a clear portrait of a company's ideal customer by ...

  • customer insight (consumer insight)

    Customer insight, also known as consumer insight, is the understanding and interpretation of customer data, behaviors and ...

  • buyer persona

    A buyer persona is a composite representation of a specific type of customer in a market segment.

Close