Volatile memory is a type of storage whose contents are erased when the system's power is turned off or interrupted. An example of volatile memory is RAM (random access memory).
When you are working on a document, it is kept in RAM. If the computer you're using is disconnected from power, your work is lost because it was not stored in permanent (non-volatile) memory. For this reason, we recommend saving your documents or other data to a non-volatile storage medium, such as a hard drive, SSD, or USB stick.
Volatile memory is also sometimes referred to as temporary storage.
Why do computers have volatile memory?
Volatile memory is much faster than non-volatile memory. However, it is also more expensive. Computers use volatile and non-volatile memory to help balance cost with performance. As faster technologies like NVMe become cheaper, it's possible in the future that computers may only use non-volatile memory.