One of the main reasons why we need information systems is because they improve efficiency, which can boost productivity. They typically support data-intensive operations. In business organizations, a well-designed information system can be the difference between profit and loss.
Every organization runs on information and each business entity has a particular way of gathering, recording, storing and manipulating information. Trivially, all that is needed to collect and store information is a pen and paper. However, it would be a phenomenal task, for instance, for a medical practitioner to record and store patient details using pen and paper. Information systems have completely revolutionized the collection, storage and manipulation of data.
An information system generally comprises a series of specialized computer applications and hardware that process vast amounts of data to provide useful information in processes such as decision making. Some definitions refer to the whole architecture, comprising software applications, hardware, operating systems and the network structure that supports the various computing components making up the information system.
Information systems evolve with time as technology advances and as formal rules governing information management in an organization change. For instance, if there are major structural changes in an organization, comparable changes in the information system may be required.