 An Information System (IS) is a collection of interrelated components that collect, process, store, and provide as output the information needed to complete a business task.  Every IS deals with three components: ◦ Data ◦ Information ◦ Data flows ◦ Processing Logics

 Data are raw facts that describe people, objects and events in organization (e.g. name, age, customer’s account number). Data is used in an IS to produce information.  Information is data organized in a form that human can interpret  Data flows are group of data that move and flow through a system. They include a description of the sources and destinations for each data flow  Processing logic describes the steps that transform the data and events that trigger these steps.

Data, Data Flow And Processing Logics

 As far as organizations perform many different types of activity, they require several different types of information systems to support all of information needs. The information systems found in most businesses include ◦ Transaction processing systems ◦ Management information systems ◦ Executive information systems ◦ Decision support systems ◦ Expert systems ◦ Communication support systems ◦ Office support systems

 Transaction processing systems (TPS) capture and record information about the transactions that affect the organization. A transaction occurs each time a sale is made, supplies are ordered, an interest payment is made. Usually these transactions create credit or debit entries in accounting ledgers. This kind of ISs were among the first to be automated by computers. The modern TPS use state-of-the-art technology, for instance, in the form of on-line TPS.  Management information systems (MIS) are systems that take information captured by TPS and produce reports that management needs for planning and controlling the business. MIS are possible because the information has been captured by the TPS and placed in organizational databases.

 Executive information systems (EIS) provide information for executives to use in strategic planning. Some of the information comes from the organizational databases, but much of the information comes from external sources – news about competitors, stock market reports, economic forecasts, and so on.  Decision support systems (DSS) allow a user to explore the impact of available options or decisions. Whereas an MIS produce reports, DSS provide an interactive environment in which decision makers can quickly manipulate data and models of business operations. A DSS has three parts. The first part is composed of a database (which may be extracted from TPS or MIS). The second part consists of mathematical or graphical models of business processes. The third part is made up of a user interface (or dialogue module) that provides a way for the decision makers to communicate with the DSS. An EIS is a DSS that allows senior management to explore data starting at a high level of aggregation and selectively drill down into specific areas where more detailed information and analysis are required.

 Expert systems (ES) replicate the decision-making process rather than manipulating information. If-then-else rules or other knowledge representation forms describe the way a real expert would approach situations in a specific domain of problems. Typically, users communicate with an ES through an interactive dialogue. The ES asks questions (which an expert would ask) and the end user supplies the answers. Those answers are then used to determine which rules apply, and the ES provides a recommendation based on the rules.  Communication support systems (CSS) allow employees to communicate with each other and with customers and suppliers. Communication support now includes , fax, Internet access, and video conferencing.  Office support systems (OSS) help employees create and share documents, including reports, proposals, and memos. OSS also help to maintain information about work schedule and meetings.

 Maintainability  Dependability  Efficiency  Usability

 Production Sub System: It is concerned with decision making activities related to production and services with predefined specifications and standards.  Material Management System: It is concerned with the control of material in such a manner which ensures maximum return on working capital.  Financial Management System: It is concerned with proper utilization of funds. The funds must be utilized in purchasing a proper mix of various types of assets.

 Personnel Management System: It deals with the people at work and also with planning of man power, recruitment, selection procedure placement, orientation and training session of employee.  Marketing Management: It is concerned with handling and transportation of goods from the point of production to the point of consumption. Thus filling the gap in between consumer and producer.  Real Time and Distributed Systems: A system is a real- time system when it can support the execution of applications with time constraints on that execution. Where as A distributed system consists of multiple autonomous computers that communicate through a computer network. The computers interact with each other in order to achieve a common goal.

 Manual systems ◦ Use paper + pencil technology ◦ Overall objective has to be found manually e.g. Auditing  CBIS ◦ Information system that rely on computer hardware and software for processing and disseminating information. CBIS can only exist if there is a manual system.

 System Models are used to understand and represent systems. System Models are generated during logical design phase. ◦ System Analysts: These are the People involved in System Modeling. ◦ System Users: These are the People who validate Models. ◦ Project Manager: These are the People who ensures that the model meets standards.