Chap03 Computer Hardware

Chapter 3 Computer
Hardware
James A. O'Brien, and George Marakas.
Management Information Systems with MISource
2007, 8th
ed. Boston, MA: McGraw-Hill, Inc.,
2007. ISBN: 13 9780073323091

Chapter 3 Computer Hardware 2
Pre-Computer Calculations
 Counting on fingers and toes
 Stone or bead abacus
Calculate comes from calculus, the Latin word
for stone
 1642: first mechanical adding machine
Invented by Blaise Pascal
Wheels moved counters
Modified in 1674 by Von Leibnitz
 Age of industrialization
Mechanical loomed used punch cards

Early Computing
 19th Century
Charles Babbage proposed the Analytical
Engine, which could calculate, store values in
memory, perform logical comparisons
Never built because of lack of electronics
 1880s
Hollerith’s punched cards used to record
census data using On/Off patterns
The holes turned sensors On or Off when run
through tabulating machine
This company became the foundation for IBM

Electronic Computers
 1946 - First Generation Computer
ENIAC
Programmable
5000 calculations per second
Used vacuum tubes
Drawbacks were size and processing ability
 1950s
ENIAC replaced by UNIVAC 1, then the
IBM 704
Calculations jumped to 100,000 per second

Waves of Computing
 Late 1950s - Second Generation
Transistors replaced vacuum tubes
200,000 to 250,000 calculations per second
 Mid-1960s - Third Generation
Integrated circuitry and miniaturization
 1971 - Fourth Generation
Further miniaturization
Multiprogramming and virtual storage
 1980s - Fifth Generation
Millions of calculations per second

Microcomputers
 1975
ALTAIR flicking switches
 1977
Commodore and Radio Shack produce
personal computers
 1979
Apple computer, the fastest selling PC thus far
 1982
IBM introduced the PC, which changed the
market

Categories of Computer
Systems

Microcomputer Systems
 Usually called a personal computer or PC
 Computing power now exceeds that of the
mainframes of previous generations
 Relatively inexpensive
 Are the networked professional workstations
used by business processions
 Versions include hand-held, notebook, laptop,
tablet, portable, desktop, and floor-standing

Recommended PC Features
Business Pro Multimedia Heavy Newcomer
2-3 GHz processor Mac G4 or 2-3 GHz
Intel processor
1-2 GHz Celeron
processor
512MB RAM 512MB RAM 256MB RAM
80GB hard drive 120GB+ hard drive 40GB hard drive
18-inch flat-panel
display
18-inch or larger CRT,
flat-panel LCD, or
plasma display
17-inch CRT or 15-inch
flat panel LCD
CD-RW/DVD drive or
portable hard drives for
backup
CD-RW/DVD+RW
drive
CD-RW/DVD drive
Network interface card
(NIC)
High-end color printer Internal, 56K modem
Basic speaker system Deluxe speaker system Basic inkjet printer

Microcomputer Uses
 Workstations
Supports have 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 and Internet or
intranet websites

Corporate PC Criteria
 Solid performance at a reasonable price
 Operating system ready
 Connectivity
Network interface cards
or wireless capabilities

Information Appliances
 Hand-held microcomputer devices
 Known as personal digital assistants (PDAs)
Web-enabled PDAs use touch screens,
handwriting recognition, or keypads
Mobile workers use to access email or the Web,
exchange data with desktop PCs or servers
Latest entrant is the BlackBerry
 PDAs include
Video-game consoles
Cellular and PCS phones
Telephone-based home email appliances

Midrange Systems
 High-end network servers that handle large-scale
processing of business applications
 Not as powerful as mainframes
Less expensive to buy, operate, and maintain
 Often used to manage
Large Internet websites
Corporate intranets and extranets
Integrated, enterprise-wide applications
 Used as front-end servers to assist mainframes
with telecommunications and networks

Mainframe Computer Systems
 Large, fast, powerful computer systems
Large primary storage capacity
High transaction processing
Handles complex computations
 Widely used as superservers for…
Large client/server networks
High-volume Internet websites
 Becoming a popular computing platform for…
Data mining and warehousing
Electronic commerce applications

Supercomputer Systems
 Extremely powerful systems designed for…
Scientific, engineering, and business applications
Massive numeric computations
 Markets include…
Government research agencies
Large universities
Major corporations
 Uses parallel processing
Billions to trillions of operations per second
(gigaflops and teraflops)
Costs $5 to $50 million

Computer System Concept
 A system of hardware devices organized by
function
Input
 Keyboards, touch screens, pens,
electronic mice, optical scanners
 Converts data into electronic form for entry
into computer system
Processing
 Central Processing Unit (CPU)
 CPU subunits: arithmetic-logic and control
unit

Output
 Video display units, printers, audio response
units,
and so on
 Converts electronic information into human-
intelligible form
Storage
 Primary storage (memory)
 Secondary storage (disk drives)
Control
 CPU controls other components of the system

Computer Processing Speeds
 Early computers
Milliseconds (thousandths of a second)
Microseconds (millionths of a second)
 Current computers
Nanoseconds (billionth of a second)
Picoseconds (trillionth of a second)
 Program instruction processing speeds
Megahertz (millions of cycles per second)
Gigahertz (billions of cycles per second)
 Commonly called the “clock speed”

Computer Processing Speeds
 Throughput
The ability to perform useful computation or
data processing assignments during a given
period
 Speed is dependant on…
Size of circuitry paths (buses) that interconnect
microprocessor components
Capacity of instruction processing registers
Use of high-speed cache memory
Use of specialized microprocessor, such as
math coprocessor

Moore’s Law
 A doubling in the number of transistors per
integrated circuit every 18 to 24 months
Originally observed in 1965, it holds true
today
 Common corollary of Moore’s Law…
Computing prices will be cut in half every 18
to 24 months
This has been consistently accurate
Applies to cost of storage as well

Moore’s Law

Peripherals
 Peripheral is a generic name for all input, output,
and secondary storage devices
Parts of the computer system, but not the CPU
Are all online devices
 Online devices
Separate from the CPU, but electronically
connected to and controlled by it
 Offline devices
Separate from and not under the control of the
CPU

Peripherals Advice

Input Technologies
 Keyboard - Still most widely used input device
 Graphical User Interface (GUI) - Icons, menus,
windows, buttons, bars; Selected with pointing
devices
 Electronic Mouse - Most popular pointing device;
Pressing mouse buttons initiates activity
represented by the icon selected
 Trackball - Stationary device, similar to mouse;
Roller ball moves cursor on screen
 Pointing Stick - Small eraser-head device
embedded in keyboard; Cursor moves in the
direction of the pressure placed on the stick

Input Technologies
 Touchpad
 Small, rectangular, touch-sensitive surface
 Usually on keyboard
 Cursor moves in direction your finger moves
 Touch Screen
 Use computer by touching screen Screen emits
a grid of infrared beams, sound waves, or
electric current
 Grid is broken when screen is touched

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

Speech Recognition Systems
 Speech be the future of data entry
 Easiest, most natural means of human communication
 Recognizing speech patterns
 Discrete required pauses between each word
 Continuous speech recognition software (CSR) recognized
continuous, conversationally paced speech
 Speech recognition systems digitize, analyze, and classify
speech and sound patterns
 Compares to a database of sound patterns in its vocabulary
 Passes recognized words to the application software
 Typically requires voice recognition training
 Speaker-independent voice recognition systems
 Allows computer to recognize words from a voice it has never
heard before
 Typically used in voice-messaging computers

Optical Scanning
 Devices read text or graphics and convert them into digital input
for a computers
 Enables direct entry of data from source documents
 A document management library system
 Scans documents, then organizes and stores them for easy
reference or retrieval
 Scanners
 Compact desktop models are popular for low cost and ease of
use
 Larger, more expensive flatbed scanners are faster and
provide high-resolution color scanning
 Optical Character Recognition (OCR)
 Software that reads characters and codes
 Used to real merchandise tags, sort mail, score tests
 Optical scanning wands read bar codes

Other Input Technologies
 Magnetic Stripe
 Reads the magnetic stripe on credit cards
 Smart Cards
 Microprocessor chip and memory on credit card
 Use more in Europe than in the U.S.
 Digital Cameras
 Allows you to shoot, store, and download photos or full-
motion video with audio into the PC
 Images and audio can then be edited or enhanced
 Magnetic Ink Character Recognition (MICR)
 Used by banks to magnetically read checks and deposit
slips
 Requires an iron oxide-based ink
 Reader-sorter equipment magnetizes the ink, then passes
it under a reading head to sense the signal

Output Technologies
 Video Displays
Cathode-ray tube (CRT)
Liquid crystal displays (LCDs)
 Active matrix and dual scan
Plasma displays
 Used in large TVs and flat-panel monitors
 Printed Output
Inkjet printers spray ink on a page
Laser printers use an electrostatic process
similar to a photocopying machine

Storage Tradeoffs

Computer Storage Fundamentals
 Uses a two-state or binary representation of data
On or Off
On represents the number 1
Off represents the number 0
 Data are processed and stored in computer
systems through the presence or absence of
On/Off signals

Bit and Byte
 Bit
Short for binary digit
Smallest element of data
Either zero or one
 Byte
Group of eight bits, which operate as a single
unit
Represents one character or number

Representing Characters in Bytes

Using Binary Code to Calculate

Storage Capacity Measurement
 Kilobyte (KB): one thousand bytes
 Megabyte (MB): one million bytes
 Gigabyte (GB): one billions bytes
 Terabyte (TB): one trillion bytes
 Petabyte (PB): one quadrillion bytes

Direct and Sequential Access
 Direct or Random Access
 Directly store and retrieve data
 Each storage position has a unique address and can be
accessed in the same length of time
 Semiconductor memory chips, magnetic disks
 Sequential Access
 Data is stored and retrieved sequentially
 Must be accessed in sequence by searching through prior
data
 Magnetic tape

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

Types of Semiconductor Memory
 Random Access Memory (RAM)
Most widely used primary storage medium
Volatile memory
Read/write memory
 Read-Only Memory (ROM)
Permanent storage
Can be read, but not overwritten
Frequently used programs burnt into chips
during manufacturing process
Called firmware

Flash Drives
 Sometimes referred to as a jump drive
Uses a small chips containing
thousands of transistors
Can store data for virtually
unlimited periods without power
Easily transported and highly
durable
Storage capacity of up to 1 GB
Plugs into any USB port

Magnetic Disks
 Used for secondary storage
 Fast access and high capacity
 Reasonable cost
 Types of Magnetic Disks
 Floppy Disks (diskettes)
 Magnetic disk inside a plastic jacket
 Hard Disk Drives (hard drives)
 Magnetic disk, access arms, and read/write heads in
sealed module for stable environment
 Fixed or removable
 Capacity from several hundred MBs to
hundreds of GBs

RAID Storage
 Redundant Arrays of Independent Disks
Disk arrays of hard disk drives
Provides virtually unlimited online storage
Combines from 6 to more than 100 small hard
disk drives into a single unit
Data are 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

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

Optical Disks

Uses of Optical Disks
 Image processing
Long-term storage of historical image files
Storage of scanned documents
 Publishing medium
Allows fast access to reference materials
Catalogs, directories, and so on
 Interactive multimedia applications
Video games, educational videos, and so on

Radio Frequency Identification (RFID)
 One of the newest and 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

RFID Versus Bar Coding
 RFID
Scans from greater distance
Can store data
Allows more information to be tracked
 Privacy concerns
Invisible nature of the system
Capacity to transmit fairly sophisticated
messages

Chap03 Computer Hardware

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