Introduction to Information System
Ndede2013 1
THE SYSTEM CONCEPT
Definition: The term system has its roots in the Greek word systema, which means an organised relationship among functioning units or components. Presently there are many definitions given to the word system. Some dictionary definitions include:
-
1. A group of things or parts working together in a regular relation, e.g. the digestive system
2. An ordered set of ideas, theories, principles etc.
3. Orderliness
An analysis of many such definitions reveals the following: -
(a) A system is designed to fulfil a pre-determined objective(s)
(b) A system has multiple components
(c) The system components are interlinked and interdependent i.e. there is cohesion. (d) A system may comprise of small sub-systems.
Hence, we may define a system as "an orderly grouping of interdependent components linked together according to a plan to achieve a specific objective". The objective may be real or stated. It is worth noting however, that it is not uncommon for an organisation to state one objective, and yet operate to achieve another. The crucial thing is to know the central objective of a computer application early in the analysis, so that the designed system reflects the user needs. Features of systems Theory
1. All systems are composed of inter-related parts or sub-systems and the system can only be explained as a whole. This is known as holism or synergy. The systems view is that the whole is more than just some of the parts and those vital interrelationships will be ignored and misunderstood if the separate parts are studied in isolation.
Ndede2013 2
2. Systems are hierarchical, that is, the parts and sub-systems are made up of other smaller parts. For example, a payroll system is a subsystem of the
Accounting System, which is a sub of the whole organisation. One system is a sub of another.
3. The parts of a system constitute an indissoluble whole so that no part can be altered without affecting other parts. Many
THE SYSTEM CONCEPT
Definition: The term system has its roots in the Greek word systema, which means an organised relationship among functioning units or components. Presently there are many definitions given to the word system. Some dictionary definitions include:
-
1. A group of things or parts working together in a regular relation, e.g. the digestive system
2. An ordered set of ideas, theories, principles etc.
3. Orderliness
An analysis of many such definitions reveals the following: -
(a) A system is designed to fulfil a pre-determined objective(s)
(b) A system has multiple components
(c) The system components are interlinked and interdependent i.e. there is cohesion. (d) A system may comprise of small sub-systems.
Hence, we may define a system as "an orderly grouping of interdependent components linked together according to a plan to achieve a specific objective". The objective may be real or stated. It is worth noting however, that it is not uncommon for an organisation to state one objective, and yet operate to achieve another. The crucial thing is to know the central objective of a computer application early in the analysis, so that the designed system reflects the user needs. Features of systems Theory
1. All systems are composed of inter-related parts or sub-systems and the system can only be explained as a whole. This is known as holism or synergy. The systems view is that the whole is more than just some of the parts and those vital interrelationships will be ignored and misunderstood if the separate parts are studied in isolation.
Ndede2013 2
2. Systems are hierarchical, that is, the parts and sub-systems are made up of other smaller parts. For example, a payroll system is a subsystem of the
Accounting System, which is a sub of the whole organisation. One system is a sub of another.
3. The parts of a system constitute an indissoluble whole so that no part can be altered without affecting other parts. Many