Introduction to Computers 1. Chapter Objectives 2 Understand how computers began and evolved into what they are today. Identify main computer components.

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CHAPTER 3

Introduction to Computers

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Chapter Objectives

•Understand how computers began and evolved into

what they are today.

•Identify main computer components and understand

basic functions.

•Be able to identify the different types of computers.

•Understand computer networks and differentiate LANs,

MANs, and WANs.

•Identify the basic software applications needed to work

on a computer.

•Understand basic flowcharting and decision making.

•Have a basic knowledge of several programming

languages and their use.

•How computers read and interpret data.

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One of the first programmable devices wasthe Jacquard loom.

History of Computers

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The history of the modern computer begins with two separate

technologies—that of automated calculation and that of programmability.

Examples of early mechanical calculating devices are the abacus, the

slide rule, the astrolabe and the Antikythera mechanism

Hero of Alexandria (c. 10-70 AD) built a mechanical theater which

performed a play lasting ten minutes and was operated by a complex

system of ropes and drums that might be considered to be a means of

deciding which parts of the mechanism performed which actions and

when. This is the essence of programmability.

History of Computers

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Earliest Programmable Analog Computer

The “castle clock,” an astronomical clock inventedby the Arabian Inventor /mechanical engineer; Al-Jazariin 1206, considered to be the earliest programmable analog computer. It displayed the zodiac, the solar and lunar orbits, a crescent moon-shaped pointer travelling across a gateway causing automatic doors to open every hour, and five robotic musicians who play music when

struck by levers operated by a camshaft attached to a water wheel. The length of day and night could be re-programmed every day in order to account for thechanging lengths of day and night throughout the year.

History of Computers

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In 1801, Joseph Marie Jacquard made an improvement to the textile loom that used a series of punched paper cards as a template to allow his loom to weave intricate patterns automatically.

The resulting Jacquard Loom was an important step in the development of computers because of the use of punched cards to define woven patterns can be viewed as an early form of programmability.

History of Computers

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In 1837, Charles Babbage was the first to

conceptualize and design a fully

programmable mechanical computer that he

called "The Analytical Engine.” Due to

limited finances, and an inability to resist

tinkering with the design, Babbage never

actually built his Analytical Engine.

History of Computers

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Large-scale automated data processing of

punched cards was performed for the U.S.

Census in 1890 by tabulating machines

designed by Herman Hollerith and

manufactured by Computing Tabulating

Recording Corporation, which later became

IBM.

History of Computers

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By the end of the 19th century a number of technologies that would later prove useful in the realization of practical computers had begun to appear:

Punched card Boolean algebra Vacuum tube (thermionic valve) Teleprinter

History of Computers

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Types of Computers

There are four main types of computers:

• Supercomputers

• Mainframe computers

• Minicomputers

• Microcomputers.

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Very powerful machines, used by large corporations or organization. CRAY and IBM’s Blue Gene are considered the fastest computers in the world.

Types of Computers

Supercomputer

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Capable of great processing speeds and data storageLess powerful than a supercomputerStores and processes data centrally for the entire organizationAccessed via large number of terminals

Types of Computers

Mainframe Computer

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Used for a specific purpose by medium-sized companiesor departments of large corporations. You will find themused to monitor certain processes; in universities, factories or financial institutions.

Types of Computers

Minicomputer

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They are the least powerful computer but also the leastexpensive and the fastest growing type, and most widely used computers. This is your PC or laptop most likely.

Types of Computers

Microcomputer

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Types of Microcomputers

Desktop computers/Personal Computer Designed for use at a desk or table. Typically larger and more powerful than other

types of personal computers. Desktop computers are made up of separate

components.

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Types of Microcomputers

Handheld Computer Also called PDA’s. Small and battery powered. Use touch screen or stylus. Useful for appointments, addresses, phone

numbers etc.

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Types of Microcomputers

Laptop or Notebook/Netbook Computer Lightweight mobile PCs with a thin screen. Small and battery powered. Unlike desktops, CPU, screen and keyboard all in

one case.

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Types of Microcomputers

Tablet PC Computers Mobile PCs that combine features of laptops and

handheld. Small and battery powered. Powerful and have touch screen.

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Computer Components and Functions

Input devices:

Keyboard Mouse Keypad Tablet Pen

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Computer Components and Functions

Processing:

Computer processing is the explanation of how information gets from the user to the computer. We input information into the computer using input devices such as the keyboard. The information is stored in temporary memory. When it leaves the temporary memory, the Processor acts as the commander and passes the instructions to the various parts of the computer.

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Computer Components and Functions

Memory:

There are three types of memory; RAM, Cache, and ROM. Memory stores data, while and after it is being processed by the computer. Some memory stores the data temporarily, other types of memory stores the data permanently.

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Computer Components and Functions

Output Devices:

Make the information resulting from processing available for use. The output from computers can be presented in many forms, such as a printed report or displayed on a screen.

Most common are printers and monitors.

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Computer Components and Functions

Storage:

Used to store instructions, data, and information when they are not being used in memory.

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What is Inside your Computer

MotherboardCPUMemoryVideo CardPower SupplyStorage Hard diskCD or DVD Drive

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In computers, it is running more than one program at the same time.  For instance, many people like to run Internet Explorer along with their word processing software

Multitasking/Multiprocessing

Multitasking:

Multiprocessing:

Multiprocessing is the use of two or more Central Processing Units(CPUs) within a single computer system. Sometimes Multiprocessing refers to the execution of multiple concurrent software processes in a system as opposed to a single process at any one instant.

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Networking is a series of computer linked and working together. In every small, medium, or large organization, there is a need for Networking. Networking means linking computer together to share resources, and information.

Networking and the Internet

Networking

Network Types:

LAN, MAN and WAN

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Simple Flowchart

A flowchart is common type of chart that represents an algorithm or process showing the steps as boxes of various kinds, and their order by connecting these with arrows. Flowcharts are used in designing or documenting a process or program in various fields.

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How Computers Read and Interpret Data

The Digital World:

Computers cannot recognize information the same way humans do. We process and follow instructions based on different format; text, data, pictures, sound,…etc. If you want somebody to go right, you can simple draw an arrow pointing right, or if you want somebody to add two numbers; you could say or type, add 5 and 10. However computers cannot process such a request, they can only process digital electronic signals. So our instructions have to convert to digital electronic signals so the computers can understand and execute.

Numeric RepresentationThe binary system is used to represent data and instructions; it is a two-state system; On and Off; being 1 is On, and 0 is off. Each 0 or 1 is called a bit; short for binary digit. In order to represent numbers, letters, and special characters, bits are combined into groups of eight bits called bytes. Each byte can store one letter or one digit. So when you enter a number into a computer system, the number has to be converted into a binary number before the computer can process it. However, binary numbers are hard to work with because they require so many digits, so are often represented in a format more readable by humans. The hexadecimal systemor hex, uses 16 digits (0,1, 2, 3, 4, 5, 6, 7, 8, 9, A, B, C, D, E, F)to represent binary numbers. One hex digit represents four binary digits, and two hex digits are commonly used together to represent 1 byte (8 binary digits).

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End of Chapter

Chapter Three Complete