If you are having a hard time distinguishing between the various types of data storage devices and types, then it will help you to know the following terms. Know the difference between non-volatile memory and volatile memory. Non-volatile memory does not require electric power, and so you can maintain your data storage over a long period.

You will also want to differentiate between static memory and dynamic random access memory. Both are forms of volatile memory, but static memory never needs to be refreshed. Data storage also has a difference when you consider mutability. There is read only storage, and data storage that will let you read or write.