1 Lecture 1 Information Systems and Technology: Basic Concepts ITEC 1000 “Introduction to Information Technology” Prof. Peter Khaiter

2 Lecture Template: System’s Concept & Characteristics System’s Concept & Characteristics Feedback and Control Feedback and Control System’s Study & Thinking System’s Study & Thinking Information Systems & Technology Information Systems & Technology Concepts of Separation & IS Design Concepts of Separation & IS Design Types of Information Systems Types of Information Systems Computer systems Computer systems Typical components Typical components Brief history Brief history

3 I. General Systems Theory 1. System’s Concept Def. A System is a set of components that interact with one another and serve for a common purpose or goal. Systems may be: (1) abstract or (2) physical. An abstract system is conceptual, a product of a human mind. That is, it cannot be seen or pointed to as an existing entity. Social, theological, cultural systems are abstract systems. None of them can be photographed, drawn or otherwise physically pictured. However, they do exist and can be discussed, studied and analyzed. A physical system, in contrast, has a material nature. It is based on material basis rather than on ideas or theoretical notions. Either system has nine main characteristics (Fig. 1-1): 1.Components. 6. Input. 2.Interrelationships. 7. Output. 3.Boundary. 8. Interface. 4.Purpose. 9. Constraints. 5.Environment.

4 FIGURE 1-1 Characteristics of a system System’s Concept (cont’d)

5 2. System’s Characteristics A component is either an irreducible part or an aggregate of parts, also called a subsystem. The simple concept of a component is very powerful. For example, in case of an automobile we can repair or upgrade the system by changing individual components without having to make changes the entire system. The components are interrelated; that is, the function of one is somehow tied to the function of the others. For example, in the Store system the work of one component, such as producing a daily report of customer orders, may not progress successfully until the work of another component is finished, such as sorting customer orders by date of receipt. A system has a boundary, within which all of its components are contained and which establishes the limits of a system, separating it from other systems. All of the components work together to achieve some overall purpose: the system’s reason for existing.

6 System’s Characteristics (cont’d) A system operates within an environment – everything outside the system’s boundary. The environment surrounds the system, both affecting it and being affected by it. For example, the environment of a university includes prospective students, foundations, funding agencies and the new media. Usually the system interacts with its environment. A university interacts with prospective students by having open houses and recruiting from local high schools. The point at which the system meets its environment are called interface. A system must face constraints in its functioning because there are limits to what it can do and how it can achieve its purpose within its environment. Some of these constraints are imposed inside the system (e.g., a limited number of staff available). Others are imposed by the environment (e.g., due to regulations). A system interact with the environment by means of inputs and outputs. Input is anything entering the system from the environment; output is anything leaving the system crossing the boundary to the environment. Information, energy, and material can be both input and output in relation to the environment. People, for example, take in food, oxygen, and water from the environment as input. An electrical utility takes on input from the environment in the form of raw materials (coal, oil, water power, etc), requests for electricity from customers. It provides for output to the environment in the form of electricity.

7 3. Feedback and Control in a System Very often output’s data are returned to the input of the system, as shown in Fig. 1-2, and used to regulate the system’s activity. FIGURE 1-2 Regulation of activity Such a process is called feedback. It helps to adjust the system to changes so that the system operates in a balanced state, or equilibrium. Large hotels and motels, for instance, ask guests to fill out cards evaluating the services. This feature of a system is used in control. Def. Control is the process that measures current performance and guides it toward a predetermined goal. Two types of feedback are related to system control.

8 Feedback and Control in a System (cont’d) Negative feedback is corrective feedback that helps maintain the system within a critical operating range and reduces performance fluctuations around the norm or standard. Negative feedback is transmitted in feedback control loops. As shown in Figure 1-3, a sensor detects the effect of output on the external environment; this information is returned to the system as an input, and necessary adjustments are made according to predetermined goal. In contrast to negative feedback, which is corrective, positive feedback reinforces the operation of a system by causing it to continue its performance and activities without changes. FIGURE 1-3 Feedback control loops

9 4. Methods of system’s study There are several important system’s concepts that help to study a system and understand its functioning: Decomposition Modularity Coupling Cohesion Decomposition is the process of breaking down a system into its smaller components. These components may themselves be systems (subsystems) and can be broken down into their components as well. How does decomposition aid understanding of a system? It results in smaller and less complex pieces that are easier to understand than larger, complicated pieces. Modularity is a direct result of decomposition. It refers to dividing a system into chunks or modules of a relatively uniform size. Modules can represent a system simply, making it easier to redesign and rebuild. For instance, a portable CD player, as a system, accepts CDs and settings of volume and tone as inputs and produces music as output. It includes the separate systems as its subsystems: 1) read the digital signals from CDs; 2) amplify the signals; 3) turn the signals into sound waves; and 4) control the volume and tone of the sound (see Figure 1-4).

10 Methods of system’s study (cont’d) FIGURE 1-4 Decomposing a CD system Coupling means that subsystems are dependent on each other. But they should be as independent as possible. If one subsystem fails and other subsystems are highly dependent on it, the others will either fail themselves or have problems functioning. Cohesion is the extend to which a subsystem performs a single function. In the CD player example, signal reading is a single function.

11 5. “Systems” Thinking Being able to identify something as a system Being able to identify subsystems Identifying system characteristics and functions Identifying where the boundaries are (or should be) Identifying inputs and outputs to systems Identifying relationships among subsystems

12 II. Information Systems and Technology 1. Information System, Subsystem and Supersystem Both control and management have an informational nature, that is among all the possible inputs and outputs (information, energy, and matter) they use the only one – information. Information is the central core of all resources in feedback loops while regulating the system activities. Any organization as a system could not survive without information. They need to develop a special system for processing and handling the information flows. Information: a description of a thing or process. Technology: a set of tools with a common purpose. Information Technology: a set of tools for managing descriptions of things or processes. Def. 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. Example: A payroll system, for example, collects information on employees and their work, processes and stores that information, and than produces paychecks and payroll reports for the organization. Then information is provided to manufacturing so the department can schedule production.

13 Information System, Subsystem and Supersystem (cont’d) What are the interrelated components or subsystems(according to general definition of a system) of an IS? For example, a customer support system might have an order entry subsystem that creates new orders for customers. Another subsystem might handle fulfilling the orders, including shipping and back orders. A third subsystem might maintain the product catalog database. Every system, in turn, is a part of a larger system, called a supersystem. So the customer support system is really just a subsystem of the production system. The production system, as it is shown in Figure 1-5, includes other systems, such as inventory management and manufacturing. On the other hand we can consider an information system as a list of its components: hardware, software, inputs, outputs,data,people, and procedures (Fig.1-6).

14 Information System, Subsystem and Supersystem (cont’d) FIGURE 1-5 Information systems and subsystems

15 Information System, Subsystem and Supersystem (cont’d) FIGURE 1-6 Information system and component parts

16 Information System, Subsystem and Supersystem (cont’d) Alone with the system boundary (i.e. any inputs and outputs) of an IS, we have to consider the automation boundary. It separates the automated part of the IS (where work is done by computers) from the manual part (where work is done by the people). FIGURE 1-7 The system boundary vs. the automation boundary

17 2. Concepts of Separation Separating Data and Processes That Handle Data We can consider every IS as a three-component system: data data flows processing logic 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. Figure 1-8 shows three components of an IS.

18 Concepts of Separation (cont’d) FIGURE 1-8 Data, Data Flow and Processing Logic.

19 Concepts of Separation (cont’d) There are two approaches to IS design: Process-oriented Data-oriented The process-oriented approach is based on what the system is supposed to do. The focus is on output and processing logic. Although the data are important, they are secondary to the application. Each application contains its own files and data storage capacity. Figure 1-9(A) illustrates this situation: “personnel data” appears in two separate systems – payroll system and the project management system. If a single element changes, it has to be changed in each of the data files. This approach involves creating graphical presentations (data flow diagram and charts). The data-oriented approach is a strategy that focuses on the ideal organization of data, independent of where and how data are used within the system (see Figure 1-9(B)). This approach uses data model that describes the kinds of data needed in the system and the business relationships among the data (i.e. business rules). Table 1-10 summarizes the differences between the two approaches.

20 Concepts of Separation (cont’d) FIGURE 1-9 The Relationship Between Data and Applications: (A)Process-Oriented Approach (B)Data-Oriented Approach

21 Concepts of Separation (cont’d) Table 1-10 Key Differences Between The Process-Oriented and Data-Oriented Approaches. Separating Databases and Applications When the data-oriented approach is applied, databases are designed around subjects, such as customers, suppliers and parts. It allows to use and to revise databases for many different independent applications, what creates the principle of application independence (i.e. separation of data and definition of data from applications).

22 3. Types of Information Systems 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, and office support systems (Figure 1-11): 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.

23 Types of Information Systems (cont’d) 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.

24 Types of Information Systems (cont’d) 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.

25 Types of Information Systems (cont’d) FIGURE 1-11 Types of Information systems

26 4. Computer Systems: Foundations User Programmer System analyst System administrator/manager Web designer Design and operation: different perspectives

27 Computer Systems: Foundations Figure 1.12 A simplified credit card transaction Data Processing, Storage, Retrieval and Manipulation

28 Input-Processing-Output model Figure 1.13 A computer process

29 Basic data processing Input/output Input/output Basic arithmetic and logical calculations Basic arithmetic and logical calculations Data transformation/translation Data transformation/translation Data sorting Data sorting Searching for data matches Searching for data matches Data storage and retrieval Data storage and retrieval Data movement Data movement

30 High-Level Language Constructions Input/output Input/output Arithmetic, logical and assignment statements Arithmetic, logical and assignment statements True/false decision branching (IF- THEN-ELSE) True/false decision branching (IF- THEN-ELSE) Loops (WHILE-DO, REPEAT-UNTIL, FOR) and/or unconditional branching (GO TO) Loops (WHILE-DO, REPEAT-UNTIL, FOR) and/or unconditional branching (GO TO)

31 Computer Architecture: components Hardware (i.e., physical mechanisms) Hardware (i.e., physical mechanisms) Software (i.e., application and system instructions) Software (i.e., application and system instructions) Data (e.g., numeric, character, graphic, etc.) Data (e.g., numeric, character, graphic, etc.) Communications (i.e., data transport support – both hardware and software) Communications (i.e., data transport support – both hardware and software)

32 Typical Hardware Components Figure 1.14 A typical computer system

33 Hardware Components CPU Arithmetic/logic unit (ALU) Control unit (CU) Interface unit Memory Primary storage (main, RAM) Secondary storage (peripherals) Input/output devices (monitor, keyboard, floppy/CD/DVD drives, speaker, printer, scanner, light pen, etc.) Bus (a bundle of wires) Channels (separate processor)

34 CPU: Central Processing Unit ALU: arithmetic/logic unit ● Performs arithmetic and Boolean logic calculations CU: control unit ● controls processing of instructions ● controls movement of data within the CPU Interface unit ● moves program instructions and data between the CPU and other hardware components ● Bus: bundle of wires that carry signals and power between different components

35 Software Components Application software System software (operating system): Windows, UNIX, Mac OS, MS-DOS user interface (execute programs, enter commands, manipulate files) API: application program interface (an interface for application programs to access services of the OS, provided by kernel kernel (manages services of the OS: file management, I/O services, security, memory management and allocation, network management) Figure 1.15 Simplified OS block diagram

36 Communication Components Communication channel (provide connections) Wire cable Fiber optic Telephone line Wireless technologies Hardware modem network interface card (NIC) Software (establishes connections, controls the flow of data, directs data to the proper applications) Protocols/Standards

37 Protocols Protocols Common ground rules of communication between computers, I/O devices and software programs Examples: HTTP: between Web server and Web browsers TCP/IP: between computers on the Internet and local area networks ATAPI: between a CD-ROM and CPU

38 Standards Provide universal compatibility of data formats and protocols Created by a committee or become de facto due to popularity Examples: Computer languages: C++, Java, SQL Display standards: PostScript, MPEG-2, JPEG, GIF Character set standards: ASCII, Unicode, EBCDIC Video standards: VGA, RGB

39 Brief history

40 Brief history Ancient Greece/Rome (500 B.C.): Abacus Blaise Pascal (1642): calculating machine Joseph Marie Jacquard (1801): a loom used punched cards Charles Babbage (early 1800s): analytical engine Howard H. Aiken (1937): Mark I (first electromechanical computer using relays) John V. Atanasoff (1939): ABC (first electronic fully digital computer to solve physical equations, used vacuum tubes) ENIAC ( ): first general purpose computer John von Neumann (1945): modern computer architecture EDVAC, IAS ( ): first to use von Neumann architecture

41 Jacquard’s loom (1801) a loom used punched cards punched cards provided the program to print a particular pattern first known application of punched cards to hold a program

42 Babbage’s analytical engine (early 1800s) Figure 1.16 Block diagram of Babbage’s analytical engine

43 Babbage’s analytical engine (early 1800s) used punched cards for input data and for the program provided memory for internal storage performed calculations as specified by the program using a central processing unit, a “mill” printed output

44 Atanasoff-Berry Computer (ABC) ( ) 1997 replica of the Atanasoff-Berry Computer at Iowa State University first fully electronic digital computer used electronic vacuum tubes as components performed calculations using binary arithmetic not a general-purpose computer aimed to solve physical equations

45 ENIAC (Electronic Numerical Integrator and Computer) ( ) general purpose computer architecture performed calculations using decimal arithmetic I/O used punched cards could provide printed output programs could not be stored internally 18,000 vacuum tubes 15,000 sq. feet of space 30 tons of weight

46 John von Neumann (1945) stored program concept (a memory holds both programs and data) binary processing of data (instructions and data are binary) CPU (to include ALU and CU) and memory control unit (CU) read instructions from memory and executed them I/O handling through CU instruction set used in modern computers

47 Today… CRT Display Keyboard Mouse “The Box” CD-ROM Drive Floppy Disk Drive

48 Inside the box Motherboard

49 More inside… CPU (Central Processing Unit)

50 More inside… SIMM (Single Inline Memory Module)

51 More inside… HDD (Hard Disk Drive)

52 More inside… Power Supply

53 Modern computing

54 Modern computing

55 Modern computing

56 Modern computing

57 Thank you! Reading: Lecture slides and notes, Chapter 1