The computer hardware responsible for managing the computer’s memory system is called a memory management unit (MMU). This component serves as a buffer between the CPU and system memory. The functions performed by the memory management unit can typically be divided into three areas: hardware memory management, operating system memory management, and application memory management. Although the memory management unit may be a separate component of the chip, it is usually integrated into the central processing unit (CPU).
A stick of RAM, which is associated with a memory management unit.
The hardware associated with memory management typically includes random access memory (RAM) and memory caches. RAM is the physical storage compartment located on the hard drive. It is the main storage area of the computer where data is read and written. Memory caches are used to keep copies of certain data in main memory. The CPU accesses this cached information, which helps speed up processing time.
The memory management unit is usually integrated into the central processing unit.
When physical memory, or RAM, runs out of memory space, the computer automatically uses virtual memory on the hard drive to run the requested program. The memory management unit allocates operating system memory for various applications. The virtual address area, located in the central processing unit, is made up of a range of addresses that are divided into pages. Pages are secondary storage blocks of the same size. The automated paging process allows the operating system to use the allocated storage space on the hard drive.
Instead of the user receiving an error message that there is not enough memory, the MMU automatically tells the system to create enough virtual memory to run the application. The contiguous virtual memory space is created from a set of equal sized virtual memory blocks to run the application. This feature is the main key to making this process work effectively and efficiently, because the system does not need to create a portion of virtual memory to handle the requirements of the program. Creating various sizes of memory space to accommodate programs of different sizes causes a problem known as fragmentation. This can lead to the possibility of not having enough free space for larger programs when the total available space is really enough.
Application memory management involves the process of allocating the memory needed to run a program from available memory resources. On larger operating systems, many copies of the same application may be running. The memory management unit usually assigns an application the memory address that best suits its needs. It is easier to assign these programs the same addresses. Also, the memory management unit can allocate memory resources to programs as needed. When the operation is complete, the memory is recycled for use elsewhere.
One of the main challenges of the memory management unit is realizing when data is no longer needed and can be discarded. This frees memory for use by other processes. Automatic and manual memory management became a separate field of study because of this problem. Inefficient memory management presents a huge problem when it comes to optimal performance of computer systems.
Problems with a computer’s memory management unit may require the expertise of a hardware expert.
