This document summarizes key concepts from a lecture on information systems and technology. It defines a system as a set of interacting components that serve a common purpose. A system has characteristics like components, interrelationships, boundaries, purpose and environment. Feedback and control help regulate a system's activity. Information systems are collections of interrelated components that collect, process, store and output information to complete tasks. An information system can have subsystems and be part of a larger supersystem. The document outlines concepts for studying systems through decomposition, modularity, coupling and cohesion.

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

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

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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.

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

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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.

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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 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 forms 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)
• 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 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)
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 of a system
Identifying relationships among subsystems

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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

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

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

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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

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2. Concepts of Separation
Separating Data and Processes That Handle Data
Separating Databases and Applications
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

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

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Concepts of Separation (cont’d)
There are two approaches to IS design:
• Process-oriented
• Data-oriented
• 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)
• 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)
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)
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 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)
• 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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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 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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Types of Information Systems (cont’d)
FIGURE 1-11 Types of
Information
systems

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

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

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Input-Processing-Output model
Figure 1.13 A computer process

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

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

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

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Typical Hardware Components
Figure 1.14 A typical computer system

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Hardware Components
 CPU
Arithmetic/logic unit (ALU)
Control unit (CU)
Interface unit (IU)
 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)

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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

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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

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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

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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

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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

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Brief history

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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 (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)
•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. Punched cards
42

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

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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

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Atanasoff-Berry Computer (ABC)
(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 (Electronic Numerical
Integrator and Computer) (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)
 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…
CRT Display
Keyboard
Mouse
“The Box”
CD-ROM Drive
Floppy
Disk
Drive

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Inside the box
Motherboard

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More inside…
CPU
(Central Processing Unit)

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More inside…
SIMM
(Single Inline Memory Module)

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More inside…
HDD
(Hard Disk Drive)

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More inside…
Power Supply

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Modern computing

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Modern computing

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Modern computing

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Modern computing

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