RAM v/s ROM and Primary Storage
RAM is also volatile, losing the stored information in an event of power loss, and quite expensive. ROM is not volatile, but is not suited to storage of large quantities of data because it is expensive to produce. Primary Storage is also known as internal memory. It is the computer memory that is accessible to the CPU of a computer without the use of computer’s input/output channels. Primary storage is used to store that is likely to be in active use. Primary storage is typically very fast, as in the case of RAM. But, ROM must also be completely erased before it not impossible. Therefore, separate secondary storage, or external memory, is usually required for long-term persistent storage. Primary storage may include several types of storage, such as main storage, cache memory, and special registers, all of which can be directly accessed randomly, that is, accessing any location in storage at any moment takes the same amount of time.