Government agencies and large corporations put vast amounts of reference and financial data into long-term storage. Collections of such data are known as archives. Companies commonly use data storage as a back-up. A company duplicates valuable data and then stores the copy away from the company's place of business. The most common storage devices are magnetic units called floppy disks and hard disks.
Floppy disks are removable and are therefore used to transport data.
Most hard disks are permanently installed inside computers. Larger optical disks store archival material. The memories of the largest computers, called mainframes, hold hundreds of millions of records, pages, and even audio and video files. In addition, the international computer network called the Internet can be thought of as a data-storage device. How to cite this article.