1 lecture 1 information systems and technology: basic concepts itec 1000 “introduction to...

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Lecture 1Lecture 1Information Systems and Technology: Information Systems and Technology:

Basic ConceptsBasic Concepts

ITEC 1000 “Introduction to Information Technology”

Prof. Peter Khaiter

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Lecture Template:Lecture Template:

System’s Concept & CharacteristicsSystem’s Concept & Characteristics Feedback and ControlFeedback and Control System’s Study & ThinkingSystem’s Study & Thinking Information Systems & TechnologyInformation Systems & Technology Concepts of Separation & IS DesignConcepts of Separation & IS Design Types of Information SystemsTypes of Information Systems Computer systemsComputer systems Typical componentsTypical components Brief historyBrief history

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I. General Systems TheoryI. General Systems Theory

1. System’s Concept1. 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.

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FIGURE 1-1 Characteristics of a system

System’s Concept (cont’d)System’s Concept (cont’d)

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2. System’s Characteristics2. 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.

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System’s Characteristics (cont’d)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.

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3. Feedback and Control in a System3. 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.

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Feedback and Control in a System (cont’d)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

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4. Methods of system’s study4. 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).

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Methods of system’s study (cont’d)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.

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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

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II. Information Systems and TechnologyII. Information Systems and Technology

1. Information System, Subsystem and Supersystem 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.

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Information System, Subsystem and Supersystem (cont’d)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).

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FIGURE 1-5 Information systems and subsystems

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FIGURE 1-6 Information system and component parts

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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

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2. Concepts of Separation2. Concepts of Separation

Separating Data and Processes That Handle DataWe 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 interpretData flows are group of data that move and flow through a system. They include a

description of the sources and destinations for each data flowProcessing logic describes the steps that transform the data and events that trigger these

steps.

Figure 1-8 shows three components of an IS.

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Concepts of Separation (cont’d)Concepts of Separation (cont’d)

FIGURE 1-8 Data, Data Flow and Processing Logic.

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Concepts of Separation (cont’d)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.

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

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Concepts of Separation (cont’d)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).

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3. Types of Information Systems3. 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.

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Types of Information Systems (cont’d)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.

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• 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 e-mail, 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.

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FIGURE 1-11 Types of

Information

systems

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4. Computer Systems: Foundations4. Computer Systems: Foundations

User Programmer System analyst System administrator/manager Web designer

Design and operation: different perspectives

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Computer Systems: FoundationsComputer Systems: Foundations

Figure 1.12 A simplified credit card transaction

Data Processing, Storage, Retrieval and Manipulation

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Input-Processing-Output modelInput-Processing-Output model

Figure 1.13 A computer process

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Basic data processingBasic data processing

Input/outputInput/output Basic arithmetic and logical Basic arithmetic and logical

calculationscalculations Data transformation/translationData transformation/translation Data sortingData sorting Searching for data matchesSearching for data matches Data storage and retrievalData storage and retrieval Data movementData movement

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High-Level Language ConstructionsHigh-Level Language Constructions

Input/outputInput/output Arithmetic, logical and assignment Arithmetic, logical and assignment

statementsstatements True/false decision branching (IF-True/false decision branching (IF-

THEN-ELSE)THEN-ELSE) Loops (WHILE-DO, REPEAT-UNTIL, Loops (WHILE-DO, REPEAT-UNTIL,

FOR) and/or unconditional branching FOR) and/or unconditional branching (GO TO)(GO TO)

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Computer Architecture: componentsComputer Architecture: components

Hardware (i.e., physical mechanisms)Hardware (i.e., physical mechanisms) Software (i.e., application and system Software (i.e., application and system

instructions)instructions) Data (e.g., numeric, character, Data (e.g., numeric, character,

graphic, graphic, etcetc.).) Communications (i.e., data transport Communications (i.e., data transport

support – both hardware and support – both hardware and software)software)

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Typical Hardware ComponentsTypical Hardware Components

Figure 1.14 A typical computer system

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Hardware ComponentsHardware Components

CPUArithmetic/logic unit (ALU)Control unit (CU)Interface unit

MemoryPrimary 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)

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CPU: Central Processing UnitCPU: 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

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Software ComponentsSoftware 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 kernelkernel (manages services of the OS: file management, I/O services, security, memory management and allocation, network management)

Figure 1.15 Simplified OS block diagram

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Communication ComponentsCommunication Components

Communication channel (provide connections)Wire cableFiber opticTelephone lineWireless technologies

Hardwaremodemnetwork interface card (NIC)

Software (establishes connections, controls the flow of data, directs data to the proper applications)

Protocols/Standards

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ProtocolsProtocols

ProtocolsCommon 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 networksATAPI: between a CD-ROM and CPU

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StandardsStandards

Provide universal compatibility of data formats and protocols

Created by a committee or become de facto due to popularity

Examples:Computer languages: C++, Java, SQLDisplay standards: PostScript, MPEG-2, JPEG, GIFCharacter set standards: ASCII, Unicode, EBCDICVideo standards: VGA, RGB

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Brief historyBrief history

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Brief historyBrief 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 (1943-46): first general purpose computer John von Neumann (1945): modern computer

architecture EDVAC, IAS (1951-52): first to use von Neumann

architecture

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Jacquard’s loom (1801)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

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Babbage’s analytical engine (early Babbage’s analytical engine (early 1800s)1800s)

Figure 1.16 Block diagram of Babbage’s analytical engine

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Babbage’s analytical engine (early Babbage’s analytical engine (early 1800s)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

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Atanasoff-Berry Computer (ABC) Atanasoff-Berry Computer (ABC) (1937-39)(1937-39)

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

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ENIAC (ENIAC (EElectronic lectronic NNumerical umerical IIntegrator ntegrator aand nd CComputer) (1943-46)omputer) (1943-46)

•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

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John von Neumann (1945)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

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Today…Today…

CRT Display

Keyboard

Mouse

“The Box”CD-ROM Drive

FloppyDiskDrive

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Inside the boxInside the box

Motherboard

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More inside…More inside…

CPU(Central Processing Unit)

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SIMM(Single Inline Memory Module)

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HDD(Hard Disk Drive)

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Power Supply

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Modern computingModern computing

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