System Introduction PDF

Topic 1 Notes Overview Systems are created to solve problems. One can think of the systems approach as an organized way of dealing with a problem. Today systems affect every aspect of modern business and our personal life. Computers can improve the performance of all sectors of economy. Therefore, t...

Topic 1 Notes Overview Systems are created to solve problems. One can think of the systems approach as an organized way of dealing with a problem. Today systems affect every aspect of modern business and our personal life. Computers can improve the performance of all sectors of economy. Therefore, the greatest challenge of today is to increase business and industry productivity using the full potential of computer-related technology. A systematic study and analysis of any system is an essential pre- requisite before developing and designing an efficient application software for that system. It is important to master both the methods of system analysis and the skills and tools required for designing the application software. System Defn: A collection of components that work together to realize some objectives forms a system. A system is a set of interrelated components that function together in a meaningful way. System is an orderly grouping of interdependent components according to a plan to advise a specified task. Components A system is delimited from its environment (its suprasystem) by a boundary. A system accepts inputs at its boundaries. Outputs flow back across the boundaries. A process is an activity that changes the system in some way. Of particular interest are the interfaces, the points at which the various system components communicate or interact. As a general rule, the more interfaces a system contains, the more complex the system. In addition to inputs, processes, interfaces, and outputs, the system also includes control and feedback mechanisms that together allow the system to determine if it is achieving its purpose. Feedback is the return of a portion of the system’s output to its input. If the feedback suggests a deviation from the expected value (the control), the system reacts by attempting to adjust itself. Characteristics of a system Its main characteristics are Organization: Is arrangement of components to achieve objectives Interaction: refers to the manner in which each component functions with other components of the system. Interdependence: means those parts of the organization or computer systems depend on one another. Integration: is concerned with how a system is tied together. It is more than sharing a physical part or location. It means that parts of the system work together within the system although each part performs a unique function. Successful integration will typically produce a better result as a whole rather than if each component works independently. Central objective: Objectives may be real or stated. Although a stated objective may be the real objective, it is quite common that organization may set one objective and operate to achieve another. The important points are that users must be aware about the central objective well in advance. A decision to computerize an application is initiated by user analyzed and designed by analysts programmed and tested by programmer and run by operator. Types of systems Physical: Systems are tangible entities that may be static or dynamic. Example of static - Office desk, Chair Example of Dynamic - Programmed Computer. Abstract: Systems are conceptual or non physical entities. They may be as straight forward as formulas of relationships among set of variables or models is the abstract conceptualization of physical system. Open & closed system Open system continuously interacts with environment. It interact inputs from and delivers output to outside. Closed system is isolated from environment influence. In reality completely closed systems are rare. Man made system Man made information system is a power structure to achieve company goals and classified as follows. 1. Formal information system A Formal information system is based on the organization represented by the organization chart. The chart is a map of positions and their authority relationships, indicated by boxes and connected by straight lines. It is concerned with the pattern of authority, communication and work flow. 2. Informal information system An Informal information system is an employee-based system designed to meet personnel and vocational needs and to help in the solution of work-related problems. It also funnels information upward through indirect channels. In this way, it is considered to be a useful system because it works within the framework of the business and its stated policies. Computer based system This category of the information system mainly depends on the computer for handling business applications. System analysts develop several different types of information systems to meet a variety of business needs. There is a class of systems known collectively as Computer Based Information System. Computer based information systems are of too many types. They are classified as: Transaction processing System (TPS) Management Information Systems (MIS) Decision support system (DSS) Office Automation Systems (OAS) The system life cycle Every system has a life cycle. An information system is “born” when a problem is recognized. After the system is developed, it grows until it reaches maturity. Eventually, a change in the nature of the problem or increasing maintenance costs degrade the value of the system, so it “dies” and a new or replacement system is born to take its place.