• No products in the cart.

ISDP1: System Concepts- Introduction to Systems Pt. 1

It is informative to find out exactly what is meant by a system. A system can be defined as: an inter-related set of components that work together within an identifiable boundary to achieve some overall goals.

Put another way, a system is a collection of parts which are related to each other and which may depend on each other and which work together as a coherent whole. A system has input, process (or transform), output, feedback and control mechanisms. We are primarily concerned with organizational and information systems.

However, it is important to note that the term ‚Äėsystem‚Äô does not solely apply to computer systems. It can apply to things as diverse as the legal system, the transport system, the social services system, the solar system and even the digestive system! Any phenomenon which exhibits a relationship among interrelated components can be termed a system.

  Key Elements of a System

The Transformation Process

All systems consist of input, process and output:

  • Input: Capturing and assembling elements that enter the system to be processed e.g. raw materials, people, skills, money.
  • Processing: The transformation processes which convert input into output, e.g. a production process, a mathematical calculation, a meeting of people.


  • Output: Transferring elements that have been produced by a transformation process to their ultimate destination in a form which will be meaningful to its recipient, e.g. a product, a piece of information. In the case of information, output in the form of a report, a telephone call etc.



It is not necessary to consider all the inputs and outputs of a system, but consider only those inputs which are considered to affect the outputs and only those outputs which are relevant to the systems objectives.


Outside and Inside the System


Environment: All those external elements, whose changes in behavior, attitude etc., effect the working of the system and all those external elements, which are effected by the system’s environment.


Boundaries: The separation of a system from its environment i.e. the features or constraints which depict the scope of activities for a system and delineate areas of responsibility. The system is inside the boundary, whereas the environment lies outside. Boundaries can be imposed by the nature of the system itself or can be decided upon by management. They may be flexible, changing over time or as the wider organization changes.

Interfaces: It is the area of contact between one system boundary and another. Several systems may share the same environment and may be connected to one another by means of a shared boundary or interface.


Sub-system: A system representing a component of a larger system. Systems often consist of numerous subsystems. Each subsystem has elements, interactions with other subsystems, and objectives. Subsystems perform specialized task for the overall system. In business, functions such as marketing, finance, and manufacturing are subsystems.


  • System Performance

Two measures of system performance are:

Effectiveness: The degree to which set goals are achieved. It is therefore concerned with the results or the outputs of a system.

Efficiency: A measure of the use of inputs (or resources) to achieve results. How much money is used to generate a certain level of sales.

The efficiency and effectiveness of a system can be measured by having the following two elements built into the system:

Feedback: a flow of information from the output component to the decision-maker concerning the system’s output or performance. Indicates if the system performance is meeting standards. Based on this, the decision-maker, who acts as a control, may decide to modify the inputs or the processes or both.

Control: A major system function which monitors and evaluates system feedback, to establish to what degree system goals are being achieved

A key element in the success of a system is its ready adaptation to changes in its environment. This again emphasizes the need for monitoring and control of systems based on relevant, timely feedback.

Thus a system is composed of subsystems or components that are inter-related, has boundaries, exists within an environment, has interfaces between subsystems and with the environment, faces constraints (limitations) and receives inputs from and delivers outputs to its environment in order to fulfill its purpose (goal oriented).

   Classification of Systems

Open vs. Closed Systems

Closed Systems: A system that is cut off from its environment and does not interact with it. These systems have no exchange with the environment, i.e. all interaction goes on within the system’s own boundaries. This term normally applies to machinery where, if inputs are known, then outputs can be accurately predicted. Systems within organisations cannot be described in this way Рinteraction with other systems is an inherent characteristic of organisational systems. A closed community would be an example of a (social) closed system.

Open Systems: A system that interacts freely with its environment. It receives inputs from its environment, processes or transforms these inputs and passes outputs of various types back into its environment. In this type of system, only some of the relevant inputs can be identified, others may occur unexpectedly, for example, a company’s competitor may unexpectedly lower prices etc.


3.4.2 Adaptive Systems

A system that has the ability to change itself or its environment in order to survive

3.4.3 Deterministic vs. Probabilistic Systems

Deterministic/Mechanistic Systems: These are predictable systems where, if the inputs are known, as well as the present state of the system, then the system’s outputs can be accurately forecast. Machines and computer programs are examples.

Probabilistic/Stochastic Systems: The output of these systems can only be predicted as a probability rather than a certainty. This is true of almost all social or organizational systems as it is always impossible to account for all inputs.

3.4.4 Shared and Overlapping Sub-Systems


Systems consist of sub-systems, or in commercial terms, organizations are composed of departments and sections and these sections interact and are therefore inter-dependent. One sub-system can belong to one or more systems, therefore it can be inferred that a change to one sub-system may affect more than one system. The use of overlapping systems is often a sound economical arrangement, for example, a centralized computer facility can be used by a number of departments in an organization to reduce overall costs. Shared systems do however cause some problems. There is a need for a high level of co-ordination and in the event of change, approval will need to be sought from a number of sources, making shared systems less flexible where rapid change is needed.

  • The Systems Approach (or Systems Theory)

The Systems Approach or Systems Theory has a set of ideas with which we can view systems. This set of ideas can be summarized as follows:

All systems are composed of inter-related parts or sub-systems and the system itself can only be fully explained and understood when viewed as a whole. This is known as holism or synergy. The systems approach takes the view that the whole is greater than the sum of the parts and that by looking at separate parts of a system in isolation, vital inter-relationships will be ignored or misunderstood

Systems are hierarchical in structure, i.e. a system is made up of sub-systems and each subsystem is made up of further sub-systems. For example, your course is a sub-system of the degree courses offered by the school, which is a subset of the Faculty, subset of the National Open University. It is important to decide where to impose a boundary when attempting to analyze a system, so that, only those sub-systems which relate to your area of interest are considered.

The components of a system form an indissoluble whole so that when one part is changed, this change will effect other parts of the overall system.

When change is effected, it is important to realise what systems it does effect and what needs to be done to ensure that the changes are properly implemented.

Sub-systems need to work towards the goals of the system to which they belong and not pursue their own goals independently. Where this latter situation does occur, a condition of sub-optimization occurs. This is to be avoided if possible, but it must be recognized that in most organizations, conflicting objectives across departments is inevitable. In these cases, some form of compromise need to be reached. For example, one department’s goal may be to clear up a backlog of work. To do this they decide to work overtime. This in turn affects the Computer Services department who are quite content with leaving work at 5.00pm. How is this resolved?

  • Analyzing a System

Important questions to be answered when analyzing a system are:

  • What are its boundaries?
  • What are its inputs, processes and outputs?
  • What feedback and control mechanisms are in place?
  • How can its efficiency and effectiveness be measured?

The systems approach recommends the following steps:

  • Decompose a system into smaller, more manageable and understandable subsystems, preferably of uniform size. This facilitates the focusing of attention on one area (subsystem) at a time without interference from other parts.
  • Analyze each subsystem separately. This allows attention to concentrate on the part of the system pertinent to a particular audience, without confusing people with details irrelevant to their interest.
  • Describe the subsystems/components and their relationships with each other and the external environment.




Thus, a system is the smallest conceptual unit of a holistic structure. It is made up of many components, and each component operates on a specific set of rules and regulations. System approach is always tackled from the point of view of analyzing systems on a component basis, because understanding the components may lead to understanding the entire structure, and thus predicting and controlling it.