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CIS-100
Chapter 2—History of computers
Chapter Objectives
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After successful completion of this chapter you should be able to:






Understand how computers began and evolved into what they are
today
Identify common computer terms and understand basic computer
functions
Be able to identify the different types of computers
Understand how computer networks and the internet work
Be able to differentiate between computer hardware and computer
software
Have a basic knowledge of several programming languages and
what they are used for
The Jacquard Loom
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The Jacquard Loom
was one of the first
programmable
devices.
What is a computer?
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A computer is a
machine that
manipulates data
according to a list of
instructions.
Components of a Computer
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There are six primary components of a computer:
 Input Devices
 The Processor
 Memory
 Output devices
 Storage devices
 Communication devices
Input Devices
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Input Devices are any hardware components that
allows you to enter data, programs, commands, and
user responses into a computer.
Some of the most popular input devices include:
 Keyboard
 Mouse
The Processor
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Central Processing Unit (The Processor)—interprets and
carries out the basic instructions that operate a
computer.
The processor is made up of two different components:


Control Unit—interprets the instructions that operate a
computer.
Arithmetic/Logic Unit—performs the logical and
arithmetic processes that operate a computer.
Memory
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Random Access Memory (Ram)—consists of electronic
components that temporarily stores instructions waiting to be
executed by the processor, data needed by those
instructions, and the results of processed data (information).
Byte Abbreviation Value
 Bit b = 1 or 0 representing switch states on or off
 Byte B = 8 bits, 1 byte (1 character)
 Kilobyte KB = 1,024 bytes (1000 characters)
 Megabyte MB, = 1,048,576 bytes (1 Million characters)
 Gigabyte GB, = 1,073,741,82 4 bytes (1Billion characters)
 Terabyte TB, = 1,099,511,628,000 bytes (1 Trillion chars)
Output Devices
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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.
The two output devices more commonly used are the
printer and the monitor.
Display Devices
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Display Devices are an output devices that visually
convey text, graphics, and video information.
A monitor is a common example.
Storage Devices
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Storage devices are used to store instructions, data,
and information when they are not being used in
memory.
The most common storage devices are:
 USB Drives (Today's equivalent of the Floppy)
 Hard disk drive
 CD-Rom (Compact Disk)
 DVD-Rom (Digital Video Disk)
Hard Disk Drive
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

Magnetic Media
Capacity
 Megabytes
 Gigabytes
 Terrabytes

Disassembled hard
drive
 http://hddscan.com/do
c/HDD_from_inside.htm
l
Optical Disks
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Compact Disc (CD)
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
Digital Video Disk (DVD)
650 – 700 MB
2 types
 Recordable
(CD-R)
 Write
until full or
finalized. No Rewrite
 Rewriteable
 Write
(CD-RW)
and rewrite until
finalized

4 – 8 GB
 Approx
4 GB single layer
 Approx 8 GB dual layer
 Blue Ray
(High Def)25-50 GB, dual
layer 50-100 GB
Recordable
Re-Writeable
DVD +R
DVD +RW
DVD - R
DVD - RW
Communication Devices
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Communication devices are hardware components that
enable a computer to send (transmit) and receive
data, instructions, and information to and from one
or more computers. As such they are also
Input/output Devices.
Widely used communications devices are the NIC
(Network Interface Card), modem, and cable
modems.
Multitasking
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Multitasking is the ability to run more than one
program at the same time.
For instance, many people like to run Internet Explorer
along with their word processing software.
Types of Computers
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There are four common types of computers:
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Desktop
Laptop
Handheld
Tablet PCs
Desktop Computers
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Desktop computers are designed for use at a desk or
table. They are typically larger and more powerful than
other types of personal computers. Desktop computers
are made up of separate components. The main
component, called the system unit, is usually a
rectangular case that sits on or underneath a desk. Other
components, such as the monitor, mouse, and keyboard,
connect to the system unit.
Laptop computers
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Laptop computers are lightweight mobile PCs with a
thin screen. They are often called notebook
computers because of their small size. Laptops can
operate on batteries, so you can take them
anywhere. Unlike desktops, laptops combine the
System Unit, CPU, screen, and keyboard in a single
case. The screen folds down onto the keyboard
when not in use.
Handheld Computers
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Handheld computers, also called personal digital assistants (PDAs),
are battery-powered computers small enough to carry almost
anywhere.
Although not as powerful as desktops or laptops, handhelds are useful
for scheduling appointments, storing addresses and phone numbers,
and playing games. Some have more advanced capabilities, such as
making telephone calls or accessing the Internet. Instead of keyboards,
handhelds have touch screens that you use with your finger or a stylus
(a pen-shaped pointing tool).
Tablet PCs
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Tablet PCs are mobile PCs that combine features of
laptops and handhelds. Like laptops, they're
powerful and have a built-in screen. Like handhelds,
they allow you to write notes or draw pictures on
the screen, usually with a tablet pen instead of a
stylus. They can also convert your handwriting into
typed text. Some Tablet PCs are “convertibles”
with a screen that swivels and unfolds to reveal a
keyboard underneath.
Networking and the Internet
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Networking is a series of computers linked and
working together. In every small, medium, or large
organization, there is a need for Networking.
Networking means linking computers together to
share resources, and information.
Local Area Network
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A local area network (LAN) is a network of computers
linked together via a cable covering a small
physical area, like a home, office, or small group of
buildings, such as a school, or an airport.
Wide Area Network
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Wide Area Networks (WANs) are computers linked
together via phone, satellite or any other media. Such
computers are usually scattered in different locations.
A Wide Area Network (WAN) is a data communications
network that covers a relatively broad geographic
area (i.e. one city to another and one country to
another country) and that often uses transmission
facilities provided by common carriers, such as
telephone companies. The largest and most wellknown example of a WAN is the Internet.
Internet
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The Internet is a global system of interconnected
computer networks that interchange data by packet
switching using the standardized Internet Protocol
Suite (TCP/IP). It is a "network of networks" that
consists of millions of private networks.
IP Address
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
“Phone Number” for the computer/device

Any device connected to network has one
Approx 4.6 Billion Addresses
 5 Classes
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Class A: (8 bit) Approx 128 networks
 Range: 0.0.0.0 - 127.0.0.0
Class B: (16 bit) Approx 16,384 networks
 Range: 128.0.0.0 – 181.255.0.0
Class C: (24 bit) Approx 2,097,152 networks
 Range: 192.0.0.0 – 223.255.255.0
Class D: Multicasting
 Range 224.0.0.0 – 239.255.255.255
Class E : Experimental
IP Address
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
128.179.48.124
 Segment
1 (128): Similar to a country code in phone #
 Segment 2 (179): Similar to a area code in phone #
 Segment 3 (48) Similar to phone prefix (local area)
 Segment 4 (124) Similar to last 4 of a phone # line
specific.
Computer Hardware
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Input Devices: Keyboard, Mouse, Scanner, and
Joystick
Output Devices: Monitors, and Printers
Input/Output devices: Floppy disk, Hard disk, and
writeable CDs, and DVDs
Computer Software
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Computer software is the key to productive use of
computers. With the correct software, a computer
can become a valuable tool. Software can be
categorized into two types:
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System Software
Application Software
System Software
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System software consists of programs to control the
operations of computer equipment. An important part
of system software is a set of programs called the
operating systems. Instructions in the operating system
tell the computer how to perform the functions of
loading, storing, and executing an application program
and how to transfer data. For a computer to operate,
an operating system must be stored in the computer’s
memory. When a computer is turned on, the operating
system is loaded into the computer’s memory from
auxiliary storage. This process is called booting.
Application Software
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Application software consists of programs designed to
make users more productive and/or assist them with
personal tasks. Some widely used application
software includes web browsers, personal
information managers, project management,
accounting, computer-aided design, desktop
publishing, paint/image editing, audio and video
editing, multimedia authoring, web page authoring,
personal finance, legal, tax preparation, home
design, educational, and games.
Programming Languages
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Programming languages provide various ways of
specifying programs for computers to run.
There are thousands of different programming
languages—some intended to be general purpose,
others useful only for highly specialized
applications.
Flowchart
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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.
Flowchart Symbols
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