They serve as both storage and RAM in remote sensors and similar devices but not as the main memory in computers, phones and tablets because they are more costly (see non-volatile memory).

Non-volatile memories are not the main memory (RAM) in computers, tablets and smartphones. When only a small amount of RAM is required, non-volatile memories can actually be the main memory in ...

There are three main types of secondary storage in a computer system: solid state storage devices, such as USB memory sticks optical storage devices, such as CD, DVD and Blu-ray discs magnetic ...