One approach for extending this is to temporarily move unused RAM storage to secondary storage.

This allows us to access secondary memory as if it were a part of the main memory.

This concept provides a one-of-a-kind method for apparent primary memory extension. Virtual memory lets physical memory idealize the abstraction of the storage resources so that these resources are really accessible on a given computer. As we have mentioned above, we have limited physical memory. Virtual memory is a memory management strategy that creates an image of a very extensive memory for users. However, secondary memory such as disk is cheaper and large, and we can increase its size easily. Therefore, if physical memory initially stores the programs, the CPU can process them more quickly.Īs we mentioned above, the primary memory such as RAM is limited and costly in the system. It takes longer for the CPU to access the hard disk every time in order to execute programs. The hard disk generally stores the programs. The below figure shows a RAM known as a physical memory or primary memory: Also, it holds the instructions of programs to execute, and it is the only storage type that the CPU can access directly. To put it another way, the memory address increases in a linear fashion. Physical memory can also be accessed in a linear manner. On the other hand, power issues and interruptions have the potential to erase data from the physical memory. As a result, it needs a consistent flow to store data. Physical memory is a volatile memory, and it has a limited size because of the RAM chip. This led to modern random-access memory (RAM) of a computer is known as a physical memory or primary memory. After that, semiconductor memory has become economically competitive due to advancements in integrated circuit (IC) technology.

Until the 1970s, core memory remained in its place. By the 1950s, magnetic core memory had mostly been displaced by such unreliable and faulty technologies. As primary storage, early computers employed delay lines, Williams-Kilburn tubes, or rotating magnetic drums.

Secondary memory pictures