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Note for Cyber Security - cs by nanish aggarwal

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Nainish Aggarwal
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CYBER SECURITY UNIT I NOTES Information system (IS) is the study of complementary networks of hardware and software , that people and organizations use to collect, filter, process, create and distribute data. IS – a set of interrelated components working together to collect, retrieve, process, store, and distribute information for the purpose of facilitating planning, control, coordination, analysis, and decision making in business organization. An information system is a collection of hardware, software, data, people and procedures that are designed to generate information that supports the day-to-day, short-range, and long-range activities of users in an organization. Information systems generally are classified into five categories: office information systems, transaction processing systems, management information systems, decision support systems, and expert systems. The following sections present each of these information systems. . Components of IS The 5 components that must come together in order to produce a Computer-Based Information system are: 1. Hardware: The term hardware refers to machinery.This category includes the computer itself, which is often referred to as the central processing unit (CPU), and all of its support equipments. Among the support equipments are input and output devices, storage devices and communications devices. 2. Software: The term software refers to computer programs and the manuals (if any) that support them. Computer programs are machine-readable instructions that direct the circuitry within the hardware parts of the system to function in ways that produce useful information from data. Programs are generally stored on some input / output medium,often a disk or tape. 3. Data: Data are facts that are used by programs to produce useful information.Like programs,data are generally stored in machine-readable form on disk or tape until the computer needs them. 4. Procedures: Procedures are the policies that govern the operation of a computer system. "Procedures are to people what software is to hardware" is a common analogy that is used to illustrate the role of procedures in a system. 5. People: Every system needs people if it is to be useful. Often the most over-looked element of the system are the people, probably the component that most influence the success or failure of information systems. Why are there different types of Information System? KAMNA SINGH CYBER SECURITY NOTES

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In the early days of computing, each time an information system was needed it was 'tailor made' built as a one-off solution for a particular problem. However, it soon became apparent that many of the problems information systems set out to solve shared certain characteristics. Consequently, people attempted to try to build a single system that would solve a whole range of similar problems. However, they soon realized that in order to do this, it was first necessary to be able to define how and where the information system would be used and why it was needed. It was then that the search for a way to classify information systems accurately began. How do you identify the different types of information system in an organization? The different types of information system that can be found are identified through a process of classification. Classification is simply a method by which things can be categorized or classified together so that they can be treated as if they were a single unit. There is a long history of classification of things in the natural world such as plants or animals, however, Information systems are not part of the 'natural' world; they are created and acquired by man to deal with particular tasks and problems. The classification of information systems into different types is a useful technique for designing systems and discussing their application; it not however a fixed definition governed by some natural law. A 'type' or category of information system is simply a concept, an abstraction, which has been created as a way to simplify a complex problem through identifying areas of commonality between different things. One of the oldest and most widely used systems for classifying information systems is known as the pyramid model; this is described in more detail below. How many different kinds of Information System are there? As can be seen above, there is not a simple answer to this. Depending on how you create your classification, you can find almost any number of different types of information system. However, it is important to remember that different kinds of systems found in organizations exist to deal with the particular problems and tasks that are found in organizations. Consequently, most attempts to classify Information systems into different types rely on the way in which task and responsibilities are divided within an organization. As most organizations are hierarchical, the way in which the different classes of information systems are categorized tends to follow the hierarchy. This is often described as "the pyramid model" because the way in which the systems are arranged mirrors the nature of the tasks found at various different levels in the organization. For example, this is a three level pyramid model based on the type of decisions taken at different levels in the organization. KAMNA SINGH CYBER SECURITY NOTES

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Three level pyramid model based on the type of decisions taken at different levels in the organization Similarly, by changing our criteria to the differnt types of date / information / knowledge that are processed at different levels in the organization, we can create a five level model. Five level pyramid model based on the processing requirement of different levels in the organization What are the most common types of information system in an organization? KAMNA SINGH CYBER SECURITY NOTES

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While there are several different versions of the pyramid model, the most common is probably a four level model based on the people who use the systems. Basing the classification on the people who use the information system means that many of the other characteristics such as the nature of the task and informational requirements, are taken into account more or less automatically. Four level pyramid model based on the different levels of hierarchy in the organization A comparison of different kinds of Information Systems Using the four level pyramid model above, we can now compare how the information systems in our model differ from each other. 1. Transaction Processing Systems What is a Transaction Processing System? Transaction Processing System are operational-level systems at the bottom of the pyramid. They are usually operated directly by shop floor workers or front line staff, which provide the key data required to support the management of operations. This data is usually obtained through the automated or semi-automated tracking of low-level activities and basic transactions. Functions of a TPS TPS are ultimately little more than simple data processing systems. KAMNA SINGH CYBER SECURITY NOTES

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