Data storage, in computer science, is the use of devices to store information. Computer users store some information so that their computers can work on it almost instantly. Other information is stored only so that it can be transported from one computer to another. 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 backup. A company duplicates valuable data and then stores the copy away from the company’s place of business. If the original data should be destroyed–by fire, for example–the company can use the copy. Individual computer users also use data storage for backup of their important data.
The most common storage devices are hard drives, which typically store data on one or more rigid magnetic disks. Usually, these disks are fixed inside the drive and cannot be removed. In nearly all personal computers, an internal hard drive serves as the main storage device. Usually, a computer’s storage capacity can be expanded by adding one or more internal or external hard drives.
The memories of the largest computers hold hundreds of millions of text, image, audio, and video files. In addition, the Internet can be thought of as a distributed data-storage device. Universities, businesses, and individual computer users in virtually every country make data available “on the Net.”
Most computer software is distributed over the Internet or on optical discs called CD-ROM’s (Compact Disc-Read Only Memory units). Optical discs called DVD’s can hold even more data than CD’s. Computer users can make backup or archival copies of their data on recordable or rewritable CD’s or DVD’s. They can also back up or transport their data using tiny electronic flash drives that store data using special memory chips. Some computers and other electronic devices use flash-based storage in place of traditional magnetic hard drives.
