CH003

Computer Hardware

Chapter 3

Copyright © 2010 by the McGraw-Hill Companies, Inc. All rights reserved.McGraw-Hill/Irwin

3-2

Learning Objectives

Understand the history and evolution of computer hardware

Identify the major types and uses of microcomputer, midrange, and mainframe computer systems

Outline the major technologies and uses of computer peripherals for input, output, and storage

3-3

Learning Objectives

Identify and give examples of the components and functions of a computer system

Identify the computer systems and peripherals you would acquire or recommend for a business of your choice, and explain the reasons for your selection

3-4

Pre-Computer Calculations

Counting on fingers and toes

Stone or bead abacus– Calculate comes from calculus,

the Latin word for small stone

1642: first mechanical adding machine– Invented by Blasé Pascal, wheels moved counters– Modified in 1674 by Von Leibnitz

3-5

Pre-Computer Calculations

3-6

Pre-Computer Calculations

Age of industrialization– Mechanical loom used punch cards

Above left: Punch card reader. Above right: Punch card writer

3-7

Early Computing

19th Century– Charles Babbage proposed the Analytical

Engine, which could calculate, store values in memory, perform logical comparisons

– Never built due to of lack of electronics

1880s– Hollerith’s punched cards used to record

census data using On/Off patterns – representing digits and letters.

– The holes turned sensors On or Off when run through tabulating machine

– This company became the foundation for IBM

3-8

Electronic Computers

1946 - First Generation Computer – ENIAC (Electronic Numerical Integrator and Computer )

– Programmable

– 5000 calculations per second

– Used vacuum tubes

– Drawbacks were size and processing ability (140 square meters)

3-9

3-10

ENIAC

3-11

Electronic Computers

1950s – ENIAC replaced by UNIVAC 1, then IBM 704

– Calculations jumped to 100,000 per second

3-12

Waves of Computing

Late 1950s - Second Generation– Transistors replaced vacuum tubes– 200,000 to 250,000 calculations per second

3-13

Waves of Computing

Mid-1960s - Third Generation– Integrated circuitry and miniaturization

1971 - Fourth Generation– Further miniaturization, multiprogramming,

virtual storage

1980s - Fifth Generation– Millions of calculations per second

3-14

Microcomputers

1975– ALTAIR, programmed by flicking switches

1977– Commodore & Radio Shack produce PCs

3-15

Microcomputers

1979– Apple computer, the fastest selling PC.

1982– IBM introduced the PC, which changed the

market

3-16

Categories of Computer Systems

3-17

Microcomputer Systems

Computing power now exceeds that of the mainframes of previous generations

Called a personal computer or PC

Relatively inexpensive

Hand-held, notebook, laptop, tablet, portable, desktop, and floor-standing

Networked professional workstations used by businesses

3-18

Microcomputer Systems

3-19

Microcomputer Systems

Apollo 11 spacecraft

Apollo 11 spacecraft Today's computers

2.048 MHz CPU 4 GHz

70 Pounds 1 Pound

3-20

Recommended PC Features

3-21

Microcomputer Uses

Workstations

Supports heavy mathematical computer and graphics display demands

CAD, investment,and portfolio analysis

Network Servers

More powerful than workstations

Coordinates telecommunications and resource sharing

Supports small networks (LAN)and Internet or intranet websites

3-22

Workstations

3-23

Microcomputer Uses

Terminals

– Any device that allows access to a computer

Types

– Network (Windows or Internet)

– Intelligent

e.g. Transaction

3-24

Terminals

3-25

Network Computers

Microcomputer designed for use with internet and intranets with limited computing applications.

Operating system, applications and storage ready , from the network servers

Low TCO

Ease of software distribution and licensing

Computing platform standardization

3-26

Information Appliances

Hand-held microcomputer devices also Known as personal digital assistants (PDAs)

– Web-enabled PDAs use touch screens, handwriting recognition, or keypads so that mobile workers use to access email or the Web, exchange data(appointments, to do list) with desktop PCs or servers

– Latest entrant is the BlackBerry, iPhone

PDAs include – Video-games

3-27

Information Appliances

3-28

Midrange Systems

High-end network servers that handle large-scale processing of business applications– Not as powerful as mainframes

– Less expensive to buy, operate, maintain

Often as a powerful network server used to manage– Large Internet websites, intranets, extranets

– Integrated, enterprise-wide applications

3-29

Mainframe Computer Systems

Large, fast, powerful computer systems– Large primary storage capacity– Reduction in acquisition and operating cost (coolers)– High transaction processing– Handles complex computations

– E.g. international banks, oil companies

3-30

Mainframes

3-31

Supercomputer Systems

Extremely powerful systems designed for…– Scientific, engineering, and business applications that

requires massive numeric computations Markets include…

– Government research agencies

– Large universities

– Major corporations

– E.g. global weather forecasting

Uses parallel processing or (MPP)– Billions to trillions of operations per second

(gigaflops and teraflops)

– Price range

3-32

The Next Wave of Computing

Harnessing the infinite amount of unused computing power

Desktops and laptops within an organization

Distributed or grid computing (opposite to traditional supercomputers)

Parallel computing that relies on complete computers connected to a network

Harnesses the unused CPU power in all connected computers, even between organizations

3-33

Grid Computing

3-34

Computer System Concept

System ofhardware devices

organized byfunction

Input

Processing

Output

Storage

Control

3-35

Computer System Concept

3-36

Moore’s Law

Doubling of the number of transistorsper integrated circuit every 18 to 24 months

3-37

Computer Peripherals:

Input, output, and storage technology

3-38

Peripherals

Separate from, and not under the control of, the CPU

Offline Devices

Separate from the CPU, but electronically connected to (and

controlled by) itOnline Devices

Generic name for all input, output, and secondary storage devices

Peripheral

Parts of the computer system (not the CPU)

All online devices

3-39

Peripherals Advice

3-40

Input Technologies

Common input devices

– Keyboard– Graphical User Interface

(GUI)– Electronic mouse

and trackball– Pointing stick– Touchpad– Touch screen

3-413-41

Input technologies

Keyboard: most widely-used

Graphical user interface (GUI)

– Icons, menus, windows, buttons, bars

– Used for selection

3-423-42

Pointing Devices

Electronic Mouse

Trackball – Stationary device like a mouse

– Roller ball used to move cursor on screen.Pointing Stick – Small eraser head-like device

in keypad

– Moves cursor in direction of pressure placed on stick.

3-433-43

Pointing Devices

Touchpad – Small rectangular touch-sensitive surface

– Moves the cursor in the direction of finger moves on the pad

Touch Screen – use computer by touching screen

– Video display screen that emits a grid of infrared beams, sound waves, or a slight electric current

– Grid is broken when the screen is touched.

3-44

Pen-Based Computing

Used in Tablet PCs and PDAs– Pressure-sensitive layer, similar to touch screen,

under liquid crystal display screen– Software digitizes handwriting, hand printing, and

hand drawing

3-45

Speech Recognition Systems

Speech may be the future of data entry

– Easiest, most natural means of human communication

Recognizing speech patterns

– Discrete, requires pauses between each word

– Continuous speech recognition software (CSR) recognizes continuous, conversationally paced speech

3-46

Speech Recognition Software

Speech recognition systems digitize, analyze, and classify speech and sound patterns– Compares to a database of sound patterns

– Passes recognized words to software

– Typically requires voice recognition training

Speaker-independent systems– Allow computers to recognize words from a

voice never heard before

– Typically used in voice-messaging computers

3-47

Optical Scanning

Devices read text or graphics and convert them into digital computer input – Enables direct entry of data from source documents

Document management library system– Scans documents, then organizes and stores them

for easy reference or retrieval

3-48

Optical Scanning

Optical Character Recognition (OCR)

Software that reads characters and codes

Used to read merchandise tags, sort mail, score tests,

read bar codes

3-49

Other Input Technologies

Magnetic Stripe

Magnetic Ink Character Recognition (MICR)

Digital Cameras

Smart Cards

3-50

3-51

Output Technologies

Voice Response Increasingly found along with video displays in business

applications

Video Displays Cathode-ray tube (CRT)

Printed Output Inkjet and laser

Liquid crystal display (LCD)

Plasma displays(TVs, flat-panel monitors)

3-52

Storage Tradeoffs

3-53

Computer Storage Fundamentals

On (1) or Off (0)

Data processed & stored in computer systems through On/Off signals

Uses two-state (binary) data representation

Uses two-state (binary) data representation

Smallest element of data

Either zero or oneBitBit

Group of eight bits, which operate as a single unit

Represents one character or numberByteByte

3-54

Representing Characters in Bytes

3-55

Storage Capacity Measurement

Kilobyte (KB) One thousand bytes

Megabyte (MB) One million bytes

Gigabyte (GB) One billion bytes

Terabyte (TB) One trillion bytes

Petabyte (PB) One quadrillion bytes

3-56

Direct (Random) and Sequential Access

3-57

Direct Access

Direct or Random Access

– Also called random access.

– Directly store and retrieve data

– Each storage position has: a unique address can be accessed in the same length of time

– Represent primary storage devices such as: Semiconductor memory chips, magnetic disks.

3-58

Sequential Access

Sequential Access

– Data is stored and retrieved sequentially

– Must be accessed in sequence by searching through prior data

– Media such as: Magnetic tape known as sequential access devices.

3-59

Semiconductor Memory

Microelectronic semiconductor memory chips are used for primary storage– Advantages: small size, fast, shock and

temperature resistance– Disadvantages: volatility; must have

uninterrupted electric power or loses memory

3-60

Types of Semiconductor Memory

Random Access Memory (RAM)

Read-Only Memory (ROM)

1. Most widely used primary storage medium

2. Volatile memory

3. Read/write memory

1. Permanent storage “nonvolatile”

2. Can be read, but not overwritten

3. Frequently used programs burnt into chips during manufacturing

4. Called firmware

3-61

Flash Drives

Sometimes called a jump drive– Uses a small chip containing

thousands of transistors– Can store data for virtually

unlimited periods without power– Easily transported– Highly durable– Storage capacity of up to 20 GB– Plugs into any USB port

3-62

Magnetic Disks

Used for secondary storage– Fast access and high capacity

– Reasonable cost

Hard Disk Drives & Floppy Disks (diskettes)

3-63

RAID Storage

Redundant Arrays of Independent Disks– Provides virtually unlimited online storage– 6 to more than 100 hard disk drives are

combined into a single unit– Data is accessed in parallel, over multiple

paths, from many disks– Redundant storage of data on several disks

provides fault-tolerant capacity

Storage area networks can interconnect many RAID units

3-64

Magnetic Tape

Secondary storage– Tape reels, cassettes, and cartridges– Used in robotic, automated drive assemblies– Archival and backup storage– Lower-cost storage solution

3-65

Optical Disks

3-66

Uses of Optical Disks

Image ProcessingLong-term storage ofhistorical image files

Storage of scanned documents

Publishing MediumAllows fast access toreference materials

Catalogs, directories, and so on

Interactive Multimedia

ApplicationsVideo games, educational videos,

and so on

3-67

Radio Frequency Identification (RFID)

One of the newest, fastest growing storage technologies– System for tagging and identifying mobile objects

– Used with store merchandise, postal packages, casino chips, pets

– Special reader allows objects to be tracked as they move from place to place

– Chips half the size of a grain of sand

Passive chips derive power from reader signal

Active chips are self-powered

3-68

RFID Versus Bar Coding

Invisible nature of the system

Capacity to transmit fairly sophisticated messages

Privacy ConcernsPrivacy

Concerns

Scans from greater distance

Can store dataRFIDRFID