Every computer and server stores data. That doesnt make them data storage systems, however. Usually that term is reserved for the systems that store data for use in recreating files after some kind of computer disaster. These data storage systems can be onsite, nearby or at a remote location. There are varieties of models and media, allowing a system to be designed specifically to meet the needs of a particular company.
Models and Media
The different models of data storage systems are usually reserved for medium to large companies. Large, data-driven companies require dependable storage and a means to recreate files quickly. Whether the data is stored close by depends on the type of disaster that can be foreseen. A company based near earthquake country would be foolish to back up onsite computers with onsite servers. They would be better off to have their own servers at some distance or outsource their data storage systems needs.
For example, Wall Street companies keep mirror facilities out of state complete with desks, phones and data copies so that any damage caused by terror attacks will not close their businesses for more than a few hours. The models...