Introduction to Information Systems PDF
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Higher Institute of Computer Science and Information Systems
Dr. Amira M. Gaber
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This document is a lecture on introduction to information systems. It covers different aspects of systems, their properties, types, models, and components.
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Introduction to Information System Presented by Dr. Amira M. Gaber Lecture 1 System A system is a collection of elements or components that are organized for a common purpose. It is also, an organized collection of parts (or subsystems) that are h...
Introduction to Information System Presented by Dr. Amira M. Gaber Lecture 1 System A system is a collection of elements or components that are organized for a common purpose. It is also, an organized collection of parts (or subsystems) that are highly integrated to accomplish an overall goal. The system has various inputs, which go through certain processes to produce certain outputs, which together, accomplish the overall desired goal for the system. Components of system Introduction of Information System System Elements Elements of the System Elements of a System Outputs and Inputs The main aim of a system is to produce an output which is useful for its user. Inputs are the information that enters into the system for processing. Output is the outcome of processing. Elements of a System Processor(s) The processor is the element of a system that involves the actual transformation of input into output. It is the operational component of a system. Processors may modify the input either totally or partially, depending on the output specification. As the output specifications change, so does the processing. In some cases, input is also modified to enable the processor for handling the transformation. Elements of a System Control The control element guides the system. It is the decision making subsystem that controls the pattern of activities governing input, processing, and output. The behavior of a computer System is controlled by the Operating System and software. In order to keep system in balance, what and how much input is needed is determined by Output Specifications. Elements of a System Feedback Feedback is an indicator of current performance rates when compared to a set of standards. Positive feedback is routine in nature that encourages the performance of the system. Negative feedback is informational in nature that provides the controller with information for action. Elements of a System Environment The environment is the supra system within which an organization operates. It is the source of external elements that strike on the system. It determines how a system must function. For example, vendors and competitors of organization environment, may provide constraints that affect the actual performance of the business. Elements of a System Boundaries and Interface A system should be defined by its boundaries. Boundaries are the limits that identify its components, processes, and interrelationship when it interfaces with another system. Each system has boundaries that determine its sphere of influence and control. The knowledge of the boundaries of a given system is crucial in determining the nature of its interface with other systems for successful design. Every system has a boundary that defines its scope of activities. Constraints of a System A system must have some structure and behavior which is designed to achieve a predefined objective. Interconnectivity and interdependence must exist among the system components. The objectives of the organization have a higher priority than the objectives of its subsystems. For example, traffic management system, payroll system, automatic library system, human resources information system. Introduction of Information System System Properties Properties of a System Organization Organization implies structure and order. It is the arrangement of components that helps to achieve predetermined objectives. Interaction It is defined by the manner in which the components operate with each other. 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. Properties of a System 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. Integration Integration is concerned with how a system components are connected together. It means that the parts of the system work together within the system even if each part performs a unique function. Introduction of Information System System Types Types of a System 1. Physical or Abstract Systems Physical systems are tangible entities. We can touch and feel them. Physical System may be static or dynamic in nature. For example, desks and chairs are the physical parts of computer center which are static. A programmed computer is a dynamic system in which programs, data, and applications can change according to the user's needs. Abstract systems are non-physical entities or conceptual that may be formulas, representation or model of a real system. Types of a System 2. Open or Closed Systems An open system must interact with its environment. It receives inputs from and delivers outputs to the outside of the system. For example, an information system which must adapt to the changing environmental conditions. A closed system does not interact with its environment. It is isolated from environmental influences. A completely closed system is rare in reality. Types of a System 3. Adaptive and Non Adaptive System Adaptive System responds to the change in the environment in a way to improve their performance and to survive. For example, human beings, animals. Non Adaptive System is the system which does not respond to the environment. For example, machines. Types of a System 4. Permanent or Temporary System Permanent System persists for long time. For example, business policies. Temporary System is made for specified time and after that they are demolished. For example, A DJ system is set up for a program and it is dissembled after the program. Types of a System 5. Natural and Manufactured System Natural systems are created by the nature. For example, Solar system, seasonal system. Manufactured System is the man-made system. For example, Rockets, dams, trains Types of a System 6. Deterministic or Probabilistic System Deterministic system operates in a predictable manner and the interaction between system components is known with certainty. For example, two molecules of hydrogen and one molecule of oxygen makes water. Probabilistic System shows uncertain behavior. The exact output is not known. For example, Weather forecasting, mail delivery. Types of a System 7. Social, Human-Machine, Machine System Social System is made up of people. For example, social clubs, societies. In Human-Machine System, both human and machines are involved to perform a particular task. For example, Computer programming. Machine System is where human interference is neglected. All the tasks are performed by the machine. For example, an autonomous robot Types of a System 8. Man-made information systems are divided into three types − Formal Information System − It is based on the flow of information in the form of memos, instructions, etc., from top level to lower levels of management. Informal Information System − This is employee based system which solves the day to day work related problems. Computer Based System − This system is directly dependent on the computer for managing business applications. For example, automatic library system, railway reservation system, banking system, etc. Introduction of Information System System Models Systems Models Schematic Models A schematic model is a 2-D chart that shows system elements and their linkages. Different arrows are used to show information flow, material flow, and information feedback. Systems Models Flow System Models A flow system model shows the orderly flow of the material, energy, and information that hold the system together. Program Evaluation and Review Technique (PERT), for example, is used to abstract a real world system in model form. Systems Models Static System Models They represent one pair of relationships. The Gantt chart, for example, gives a static picture of an activity-time relationship. Systems Models Dynamic System Models Business organizations are dynamic systems. A dynamic model approximates the type of organization or application that analysts deal with. It shows an ongoing, constantly changing status of the system. It consists of Inputs that enter the system The processor through which transformation takes place The program(s) required for processing The output(s) that result from processing. What is the software? Software is a set of instructions, data or programs used to operate computers and execute specific tasks Software is a collection of instructions that enable the user to interact with a computer, its hardware, or perform tasks. For example, without your Internet browser software, you could not surf the Internet or read this page. Without an operating system, the browser could not run on your computer. Difference between Information System and Information Technology Information systems and information technology is that information systems incorporate the technology, people, and processes involved with information Information technology is the design and implementation of information, or data, within the information system.