Information System

In a general sense, the term Information System (IS) refers to a system of people, data records and activities that process the data and information in an organization, and it includes the organization's manual and automated processes. In a narrow sense, the term information system (or computer-based information system) refers to the specific application software that is used to store data records in a computer system and automates some of the information-processing activities of the organization. Computer-based information systems are in the field of information technology. The discipline of business process modelling describes the business processes supported by information systems. 

There are various types of information systems, for example: transaction processing systems, decision support systems, knowledge management systems, database management systems, and office information systems. Critical to most information systems are information technologies, which are typically designed to enable humans to perform tasks for which the human brain is not well suited, such as: handling large amounts of information, performing complex calculations, and controlling many simultaneous processes.
Information technologies are a very important and malleable resource available to executives.^[1] Many companies have created a position of Chief Information Officer (CIO) that sits on the executive board with the Chief Executive Officer (CEO), Chief Financial Officer (CFO), Chief Operating Officer (COO) and Chief Technical Officer (CTO).The CTO may also serve as CIO, and vice versa. The Chief Information Security Officer (CISO), who focuses on information security within an organization, normally reports to the CIO.
In computer security, an information system is described by the following components ^[2]:

• Repositories, which hold data permanently or temporarily, such as buffers, RAM, hard disks, cache, etc. Often data stored in repositories is managed through a database management system.
• Interfaces, which support the interaction between humans and computers, such as keyboards, speakers, scanners, printers, etc.
• Channels, which connect repositories, such as routers, cables, etc.

Information technology departments in larger organizations tend to strongly influence information technology development, use, and application in the organizations, which may be a business or corporation. A serous of methodologies and processes can be used in order to develop and use an information system. Many developers have turned and used a more engineering approach such as the System Development Life cycle (SDLC) which is a systematic procedure of developing an information system through stages that occur in sequence. An Information system can be developed in house( within the organization)or outsourced. This can be accomplished by outsourcing certain components or the entire system.^[3]

• A computer based information system, following a definition of Langefors^[4], is:
  
• a technologically implemented medium for recording, storing, and disseminating linguistic expressions,
• as well as for drawing conclusions from such expressions.

which can be formulated as a generalized information systems design mathematical program