Computer Hardware
Chapter 3
Copyright © 2010 by the McGraw-Hill Companies, Inc. All rights reserved.McGraw-Hill/Irwin
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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
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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
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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
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Pre-Computer Calculations
Age of industrialization– Mechanical loom used punch cards
Above left: Punch card reader. Above right: Punch card writer
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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
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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)
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Electronic Computers
1950s – ENIAC replaced by UNIVAC 1, then IBM 704
– Calculations jumped to 100,000 per second
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Waves of Computing
Late 1950s - Second Generation– Transistors replaced vacuum tubes– 200,000 to 250,000 calculations per second
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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
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Microcomputers
1975– ALTAIR, programmed by flicking switches
1977– Commodore & Radio Shack produce PCs
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Microcomputers
1979– Apple computer, the fastest selling PC.
1982– IBM introduced the PC, which changed the
market
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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
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Microcomputer Systems
Apollo 11 spacecraft
Apollo 11 spacecraft Today's computers
2.048 MHz CPU 4 GHz
70 Pounds 1 Pound
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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
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Microcomputer Uses
Terminals
– Any device that allows access to a computer
Types
– Network (Windows or Internet)
– Intelligent
e.g. Transaction
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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
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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
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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
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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
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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
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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
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Computer System Concept
System ofhardware devices
organized byfunction
Input
Processing
Output
Storage
Control
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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
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Input Technologies
Common input devices
– Keyboard– Graphical User Interface
(GUI)– Electronic mouse
and trackball– Pointing stick– Touchpad– Touch screen
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Input technologies
Keyboard: most widely-used
Graphical user interface (GUI)
– Icons, menus, windows, buttons, bars
– Used for selection
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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.
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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.
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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
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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
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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
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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
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Optical Scanning
Optical Character Recognition (OCR)
Software that reads characters and codes
Used to read merchandise tags, sort mail, score tests,
read bar codes
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Other Input Technologies
Magnetic Stripe
Magnetic Ink Character Recognition (MICR)
Digital Cameras
Smart Cards
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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)
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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
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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
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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.
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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.
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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
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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
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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
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Magnetic Disks
Used for secondary storage– Fast access and high capacity
– Reasonable cost
Hard Disk Drives & Floppy Disks (diskettes)
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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
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Magnetic Tape
Secondary storage– Tape reels, cassettes, and cartridges– Used in robotic, automated drive assemblies– Archival and backup storage– Lower-cost storage solution
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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
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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