Information technology (IT) is the application of computers and internet to store, retrieve, transmit, and manipulate data, or information, often in the context of a business or other enterprise. IT is considered a subset of information and communications technology (ICT). In 2012, Zuppo proposed an ICT hierarchy where each hierarchy level "contain some degree of commonality in that they are related to technologies that facilitate the transfer of information and various types of electronically mediated communications." Business/IT was one level of the ICT hierarchy.
Based on the storage and processing technologies employed, it is possible to distinguish four distinct phases of IT development: pre-mechanical (3000 BC – 1450 AD), mechanical (1450–1840), electromechanical (1840–1940), electronic (1940–present), and moreover, IT as a service. This article focuses on the most recent period (electronic), which began in about 1940.