Chapter 1: Computer
Basics.
Albert Kalim
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Computers in Our Lives
 What percentage of all Americans has Internet access at
home?
A. 20%
B. 40%
C. 60%
 True of False: The term ubiquitous computing refers to
the trend where computers are embedded in almost any
device you can think of.
 Taking a class from a remote location (your home or
office, for example) via a computer and the Internet is
called ______________________.
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Computers in Our Lives
(continued)
 Computers are prevalent in the home, in the school, in
the workplace, and on the go.
 Most professional jobs and skilled trades heavily depend
on the creation, collection, evaluation and dissemination
of information.
 Uses of computers include word processing, e-mail
exchange, shopping, research, investments
management, playing games and many other
applications.
 Knowledge of computers assists the consumer to
purchase the right computer, save money on repairs and
use the computer to maximum benefit.
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What Is a Computer and
What Does It Do?
A computer is a programmable electronic device that
accepts data and performs operations on that data.
 Input—entering data into the computer.
 Processing—performing operations on the data.
 Output—presenting the results.
 Storage—saving data, programs, or output for future use.
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Computers Then and Now
 The computer as we know it is a fairly recent invention.
 The history of computers is often referred to as
generations, from pre-computers and early computers
(before 1945) to fifth generation computers (now and the
future).
 Each new generation is characterized by a major
technological development.
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Hardware
 The physical parts of a computer are collectively known
as hardware.
 Internal hardware is located within the main box (system
unit) of the computer.
 External hardware is located outside the system unit and
plug into connectors called ports located on the exterior
of the system unit.
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Hardware (continued)
 An input device is used to input data into the computer.
 A processing device performs calculations and
comparisons necessary for processing. The main
processing device is the central processing unit (CPU).
 An output device presents the results to the user.
 Storage devices are used to save data, programs or
output.
 Communication devices allow the user to communicate
with others and access remote information.
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Software
 The programs or instructions used to tell the computer
hardware what to do.
 System software allows a computer to operate and run
application software.
 Application software performs specific tasks or
applications.
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Data and Information
 Data = raw, unorganized facts.
– Can be in the form of text, graphics, audio, or video.
 Information = data that has been processed into a useful
form.
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Computer Users and
Professionals
 Computer users, or end users, are the people who use a
computer to obtain information.
 Programmers are computer professionals whose job it is
to write the programs that computers use.
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Computer Networks and the
Internet
 A computer network links computers together so that
users can share hardware, software, and data, as well as
electronically communicate with each other.
 Network servers manage resources on a network.
 Clients are computers on the network that access
resources via the network server.
 Computer networks are commonly found in businesses,
schools, and homes.
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The Internet
 The Internet is the largest and most well-known computer
network in the world.
 Individuals connect to the Internet using an Internet
service provider (ISP).
 E-mail and accessing Web pages are two of the most
common Internet activities.
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Accessing a Network
 Need a modem or network adapter to connect to the
network.
 Software (often built into the operating system) allows
you to log on to the network and access resources.
 Need an ISP and Web browser to access Internet
resources.
 Many networks and Internet connections require a user
ID and password to log on to the network.
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Computers to Fit Every Need
Five basic categories
– Mobile devices
– Personal computers
– Midrange servers
– Mainframe computers
– Supercomputers
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Mobile Devices
 Very small computing devices.
 Usually based on a wireless phone
or pager.
 Many can be used to access e-mail
and Web pages.
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Personal Computers
 Microprocessors allow for the creation of computers
small enough to fit on a desk or lap.
 PC compatible—based on the original IBM PC; typically
run the Windows operating system.
 Macintosh—a type of personal computer manufactured
by Apple.
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Personal Computers, Cont’d.
 Desktop computers—small enough
to fit on or next to a desk. Can use:
– Desktop case
– Tower case
– All-in-one case
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Personal Computers, Cont’d.
 Portable PCs—designed to be carried around.
– Notebook computers
– Tablet PCs (either slate or convertible)
– Handheld computers (pocket computers)
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Personal Computers
(continued)
 PCs designed for just network use are referred to as
network computers (NCs) or thin clients.
 Devices designed just for Internet access are called
Internet appliances.
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Midrange Servers
 Medium-sized computers, also called minicomputers or
midrange computers.
 Fall between microcomputers and mainframes in
processing power.
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Mainframe Computers
 Standard choice for most large organizations.
 Specialize in high-volume processing of business
transactions.
 Also called high-end
servers or enterpriseclass servers.
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Supercomputers
 Used for applications that have extraordinary demands
for processing power.
 Offer very fast speeds and extreme degrees of accuracy.
 Commonly created today by
connecting hundreds of
smaller computers
to form a
supercomputing
cluster.
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Computers and Society
 The information age = the prominence of information
technology.
 There are many benefits of a computer-oriented society,
including making many tasks in our lives go much faster.
 Risks include health, security, ethical, and privacy
concerns.
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Chapter 2: Data
Representation.
Albert Kalim
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Data and Program
Representation
 Computers today are mostly digital
computers—devices that can only understand
two states.
 The two states of a digital computer are
typically represented by 0s and 1s; that is, in
binary form.
 Computers do all processing and
communications in binary form, so naturallanguage input and output are translated to and
from binary by the computer.
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The Binary Numbering System
 We normally use the decimal numbering system, which
uses 10 symbols (0, 1, 2, 3, 4, 5, 6, 7, 8, and 9).
 Computers use the binary numbering system, which
represents all numbers using just two symbols (0 and 1).
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Coding Systems for Text-Based
Data
 ASCII and EBCDIC
– Fixed-length codes that can represent any single
character of data as a string of eight bits.
 Unicode
– A longer (32 bits per character is common) code that
can be used to represent text-based data in virtually
any written language.
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Coding Systems for Other
Types of Data
 Graphics data—often stored as a bitmap which the color
to be displayed at each pixel stored in binary form.
 Audio data—waveform audio is common; MP3
compression makes audio files much smaller.
 Video data—requires a great deal of storage space, but
can be compressed.
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Machine Language
 Machine language is the binary-based code used to
represent program instructions.
 The basic set of machine language instructions that a
CPU can understand is that CPU’s instruction set.
 Most programmers rely on language translators to
translate their programs into machine language for them.
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Inside the System Unit
 The system unit of a PC is the case that houses
processing hardware and other hardware.
 All of the hardware contained within the system unit is
connected to the system board or motherboard.
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CPU
 The CPU (central processing unit) does the vast majority of
processing for a computer.
 CPUs contains a variety of circuitry and components and are
connected to the motherboard.
 Also called the processor or microprocessor.
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CPU (Continued)
 Processing speed (clock speed) is measured in
megahertz (MHz) or gigahertz (GHz) and measures the
number of clock ticks per second.
 A computer word is a group of bits or bytes that a CPU
can manipulate at one time.
 Other factors that affect the speed of the computer
include the amount of RAM and cache memory, bus
width, and bus speed.
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Memory: RAM
 RAM (random access memory) is the computer’s main
memory and is used to temporarily storage programs and
data with which it is working.
 RAM is volatile (erased when the power to the PC goes off).
 RAM comes in a variety of types, speeds, and size. Types of
RAM include:
DRAM
SRAM
SDRAM
DDR SDRAM
RDRAM
DDR-II SDRAM
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Memory: Other Types
 Cache memory—fast memory chips located on or close to
the CPU chip (L1, L2, and L3).
 Registers—high speed memory built into the CPU.
 ROM (read-only memory)—non-volatile chips inside which
data or programs are stored.
 Flash memory—non-volatile memory that can be erased and
reused. Used both within the PC and for portable storage
media (e.g digital cameras).
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Buses
 Buses are electronic paths that data travels around on a
computer system.
 Internal buses move data around within the CPU.
 Expansion buses establish links with peripheral devices.
– ISA, PCI, AGP, USB, FireWire.
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Expansion Slots and Cards
 Expansion for desktop PCs.
– Expansion cards can be inserted into expansion slots
on the motherboard.
– Some external devices can be plugged into existing
USB or FireWire ports without adding another
expansion card.
 PC cards—used with notebook PCs.
 Expansion for handhelds and mobile devices—can have
proprietary, PC card, or SDIO slot.
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Ports
 Connectors to which devices can be attached.
 Common ports:

Serial
– Keyboard

Parallel
– Mouse

SCSI
– Monitor

USB

FireWire

Network
– Modem
– MIDI
– Game
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How the CPU Works
 The CPU is a collection of electronic circuits and
components.
 Impulses from an input device passes through RAM and
enters the CPU via a system bus.
 Within the CPU the impulses move through the circuits
and components to create new impulses.
 Eventually, a set of electronic impulses leaves the CPU
for an output device.
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Typical CPU Components
Arithmetic/
Logic unit
(ALU)
Control unit
Registers
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The System Clock and the
Machine Cycle
 The system clock synchronizes the computer’s
operations.
 The machine cycle is the series of operations involved in
the execution of a single, machine-level instruction.
– Fetch
– Decode
– Execute
– Store
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Making Computers Faster Now
and in the Future
 Speeding up your system today.
– Add more memory.
– Perform system maintenance.
– Buy a larger or second hard drive.
– Upgrade your Internet connection.
– Upgrade your video card.
– Upgrade your CPU.
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Making Computers Faster Now
and in the Future (continued)
 Strategies for making faster computers.
– Moving circuits closer together.
– Faster and wider buses; faster memory.
– Improved materials (copper, SOI, new materials).
– Pipelining.
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Making Computers Faster Now
and in the Future, Cont’d.
 Strategies for making faster computers, cont’d
– Multiprocessing (multiple CPUs, each working on a
different job) and parallel processing (multiple CPUs
working together to make one job finish sooner).
– Hyperthreading.
– Improved instruction set design.
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Future Trends
 Nanotechnology—computer chips thousands of times
smaller than today’s components; built at the atomic and
molecular levels.
 Organic computers—computers containing organic
matter (biotechnology).
 Quantum computing—uses atoms or nuclei working
together as quantum bits (qubits).
 Optical chips—use light waves to transmit data.
 3-D chips—use multiple layers of circuitry or the
circuitry stands vertically.
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