SYSTEM DEVELOPMENT

SYSTEM THEORY
A system can be defined as a collection of procedures, activities, components working together to
achieve a common objective. It is an organization interactives and interdependent set of  components
working together to achieve the same goal.
A system can also be defined as an orderly grouping of interdependent components linked together
according to a plan to achieve a specific objective. The study of system concepts has three basic
implications:

i. A system must be designed to achieve a predetermined objective.
ii. Interrelationships and interdependence must exist among the components.
iii. The objectives of the organization as a whole have a higher priority than the objectives of its
subsystems.
Characteristics / features of a system:
i. Goal: System exist to achieve goals or objectives
ii. Sub-System – System are made up of subsystems or subunits that closely interact with each
other.
iii. Input: System must accept some form of input e.g. manpower and material resources. Input
captures or collects raw data from within the organization or from its external environment.
Can be describe as data entry or data capture.
iv. Processing: A series of activities which transform input into output. Processing converts this
raw input into meaningful form.
v. Output: A system must give some form of goods or services. Output transfers the processed
information to the people who will use it or to the activities for which it will be used.
Information systems requires feedback which is output that is returned to appropriate members
of the organization to help them evaluate or correct input stage.
vi. Control: Every System must have a mechanism of regulating the performance of the system
to ensure it conforms to the set standards.
vii. Environment: The system does not operate in a vacuum but must interact or be affected by
other systems i.e. supplier, competitors and technologies.

viii. Boundary: A system must have a boundary i.e. an entity that separate a system from another
system or an entity that define the extent to which the system has influence.
ix. System decay/ entropy: Entropy is a measure of the degree of disorder in a system. A system
become absolute naturally overtime mainly because of change in technology or management
policies. The concept of entropy says that any system will tend towards disorder.
2.1 PROPERTIES OF A SYSTEM
A system has the following properties: –
i. Organization
Organization implies structure and order. It is the arrangement of components that helps to
achieve predetermined objectives.
ii. Interaction
It is defined by the manner in which the components operate with each other.
For example, in an organization, purchasing department must interact with production
department and payroll with personnel department.
iii. Interdependence
Interdependence means how the components of a system depend on one another. For proper
functioning, the components are coordinated and linked together according to a specified plan.
The output of one subsystem is the required by other subsystem as input.
iv. Integration
Integration is concerned with how a system component are connected together. It means that
the parts of the system work together within the system even if each part performs a unique
function.
v. Central Objective
The objective of system must be central. It may be real or stated. It is not uncommon for an
organization to state an objective and operate to achieve another.
The users must know the main objective of a computer application early in the analysis for a
successful design and conversion.