originally Published in computer jagat magazine in 1995
Kazi Sayeda Momtaz (Sharmin)
The well known word “system” is comes from the Greek word “systema” which indicates an organized relationship among functioning units. A system exists because it is designed to achieve one or more objectives. So, a system is a set of components that act as an organic whole. In the context of programming, a system is an integrated collection of programs and data files that act as a unit. The purpose of the system is normally to process information. The output of the system is information. The input to the system is information provided by the user.
Systems have been classified in different ways. Common classifications are: (a) physical or abstract, (b) open or closed, (c) “man-made” information systems.
User area —> Systems analysis —> Programming Operations
Interdependence in a computer based system
We are familiar with various types of systems. Some of them are contained within the human body, such as the digestive and nervous systems. Some are the result of ideas, thoughts or philosophies, such as the judicial system, the democratic system and the language systems. Some provide the means of distributing some useful commodity, such as transportation systems, communication systems and electric power systems. In business, we refer to accounting, inventory, and marketing systems. Indeed, the entire universe is the most magnificent, complex, and powerful system of all.
We can recognize certain characteristics that seem to be common among most if not all systems. First, systems are made up of different parts, or components. Second, the parts are related and have definite interactions or interdependencies. Third, a change any of the components is likely to produce some sort of change in other components and in the system as a whole. Fourth, the components all work toward some particular purpose or function which is the primary object of the system as a whole. Fifth, the system usually is complex, having diverse components such as persons, ideas, materials, forces, procedures and other factors. Sixth .each system is likely to be divided into many subsystems. Further, there seems to be an infinite number of relationships possible between systems of all types.
Now components may be simple or complex, basic or advanced. They may be a single computer with a keyboard.
Memory and printer or a series of intelligent terminals linked to a mainframe. It either case, each component is part of the total system and has to do its share of work for the system to achieve the intended goal. This orientation requires an orderly grouping of the components for the design of a successful system. Interaction refers to the manner in which each component functions with other components of the system. In a computer system, the central processing unit must interact with the input device to solve a problem. In turn, the main memory holds programs and data that the arithmetic unit uses for computation. So, the interrelationship between these components enables the computer to perform. Again, interdependence means that parts of the organization or computer system depend on one another. They are coordinated and linked together according to a plan. So, the output of one subsystem is the required input for another subsystem.
Lastly, we can freely speak that a system is concerned with a function or purpose, and each person thinks in terms of the job he/she is trying to accomplish.
So, no subsystem can function in isolation because it is dependent on the inputs and it receives from other subsystems to perform its required tasks. Interdependence is further illustrated by the activities and support of systems analysts, programmers, and the operations staff in a computer center. A decision to computerize an application is initiated by the user, analyzed and designed by the analyst, programmed and tested by the programmer, and run by the computer operator. As shown in figure, none of these persons can perform properly without the required input from others.
Systems analysis is the formal study and evaluation of activities and procedures. The results of this kind of study form the foundation for managerial decisions and should therefore be presented in formalized and standardized form. Systems analysis implies the examination of each component part of the system, both as a separate entity and in relation to the whole.
Systems analysis leads logically to systems design, which is the creative act of division or inventing a partially or completely new chime for processing data.
Thus systems analysis may be defined as an analytical study that helps a decision maker to identify and select a preferred course of action among several feasible alternatives. It is a logical and systematic approach where in assumptions, objectives and criteria are clearly defined and specified. It can significantly aid a decision maker to arrive at better decisions by broadening his/her information base, by providing a better understanding of the system and interlink ages of the various subsystems, by predicting the consequences of several alternative courses of action, or by selecting a suitable course of action that will accomplish a prescribed result. Systems analysis has added a totally new dimension to the science of policy-planning and decisions-making.
Systems analysis provides the answer by methods and techniques that are available to every one for critical analysis and examination. These are not unique in the sense that anyone who has the necessary expertise and experience can exactly duplicate the analysis. The models developed can be constantly updated as more information becomes available. In contrast to other available decision-making tools that have the same limitations, systems analysis uses all the relevant information available and extracts the best components from different disciplines on which the analysis are based. Thus virtues of systems analysis are also virtues of the methods and techniques on which it is based.
Mainly the primary object of the analysis is to study the problem prior to taking action. There are four main goals of the analysis such as:
1. To define the goal or goals of the system
2. To document the goals in such a way that success of the system can later be measured.
3. To predict relevant specifications such as costs, benefits schedules and performances characteristics
4. To obtain user concurrence for each of the proceding three objectives.
As for example, for our general ledger system, the primary goal is the income report and balance sheet for each period.
In most cases, systems analysis operate in a dynamic environment where change is a way of life. The environment may be a business firm, a business application or a computer system. To reconstruct a system, the analyst must consider its elements such as outputs and inputs, processors, control, feedback, and environment.
In a concluding part we can say that the difference between a good system and a bad one is that the good system will provide a service in a more effective, economical, timely or safer manner. The bad system may provide the equivalent service, but at a higher cost or with less comfort. It is, therefore, at this point that effective cost control should be applied initially. In many applications this is called cost effectiveness, and the systems analyst speaks of a cost effectiveness or a cost-benefit analysis.