The term information system
has the following meanings:
1. A system, whether automated or manual, that comprises people, machines, and/or methods organized to collect, process, transmit, and disseminate data that represent user information.
2. Any telecommunications and/or computer related equipment or interconnected system or subsystems of equipment that is used in the acquisition, storage, manipulation, management, movement, control, display, switching, interchange, transmission, or reception of voice and/or data, and includes software, firmware, and hardware
Source: from Federal Standard 1037C and from MIL-STD-188 and from the National Information Systems Security Glossary
The simplest model that describes the Structure and Behaviour of an Information System takes five objects:
- Repositories, hold data permanent or temporarily, such as buffers, RAM, hard disks, cache, etc.
- Interfaces, exhange information with the non-digital world, such as keyboards, speakes, scanners, printers, etc.
- Networks, connect repositories, such as buses, cables, wireless links, etc.
- Services; provide value to users or to other services via messages interchange.
- Messages; carries a meaning to users or services.
Source: Vicente Aceituno
In Dana Scott's domain theory (theory of computability and approximability), an information system is used as a representation of a domain.