Memory Organization Computer Organization and Architecture by Ravinder Nath Rajotiya - January 4, 20230 Memory Organization Every computer system has following types of memory devices. The different types of memory can be explained as the memory hierarchy. Memory Hierarchy: The total capacity of the memory in a system can be visualized as a hierarchy of memory devices. It includes all memory devices employed in a computer from large size but very slow-speed to small size but very-high speed devices. The memory hierarchy can be represented as shown in figure below. IOP is used to communication between main memory and the auxiliary memory. Cache is used to communicate between CPU and the main memory. Internal or the primary memory: The internal memory consists of random access memory (RAM), read only memory (ROM) and some high-speed memory such as cache memory.