What is the difference between the main memory, cache memory and virtual memory? Why do we need each one of them?
Difference Between Main Memory, Cache Memorey And Virtual Memory
Cache memory is used to reduce the access time of CPU. Virtual memory is used to provide a virtual address space. It is not an actual memory storage unit but just a concept. The purpose of main memory is to store the data and instructions which are currently being used by the processor. They each have their own set of advantages and disadvantages. However, each one of them forms a very essential part of the CPU.
Difference Between Main Memory, Cache Memorey And Virtual Memory
The main memory of a computer is also called the primary storage, main storage, internal memory, or the physical RAM. It is often referred to simply as memory. It is the only memory directly accessible to the CPU. It is built from integrated circuits and requires electrical power to keep its information. When the power is gone, all the information it stores are also gone.
The physical RAM or main memory provides the second fastest data access in the system. The cache memory is also called the CPU memory. It is a random access memory that a processor can access much quicker than accessing a regular RAM. This is the fastest form of memory available to a computer.
This type of memory is usually integrated or built-in to the processor chip or sometimes placed on another chip that contains a separate bus interconnecting with the CPU. The cache memory is designed to store program instructions that are often referenced by software during operation. The overall performance of the application increases due to the fast access to these instructions.
The virtual memory, on the other hand, is a feature of the operating system that permits a computer to compensate or balance for shortages of physical memory. This is done by temporarily transferring pages of data from the physical RAM to the disk storage. Literally, the virtual memory is the page file or swap file which appears in drive C as “pagefile.sys”.
It appears like a normal system file on the system drive but on the operating system, it simulates a specific amount of memory or virtual memory in GB. Data access in virtual memory is a lot slower compared to the main memory and cache memory because it depends on the speed of the physical hard drive or the internal hard drive.
