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Computer Hardware
How to Choose a Multimedia
Computer
Plymouth State University
ENIAC - The First
Electronic Digital Computer
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The Four Functions of a Computer
DATA
INPUT
PROCESSING
OUTPUT
INFORMATION
STORAGE
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The System Unit
Power Supply
Hard Drives
or
CD-ROM
Drives
System Board
Floppy Drive
Expansion Card
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Directions of Computer
Development
• Miniaturization
– Transistors
– Integrated circuits
• Solid state
• Semiconductor
• Chip
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Integrated Circuit
• IC, or "chip"
• Made from Silicon
• Includes
Transistors,
Resistors &
Capacitors
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Steps in Manufacture of a
Microchip
1 Make large
drawing. Reduce
drawing hundreds
of times to
microscopic size.
2
Duplicate reduced
photo many times
on sheet.
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Etched Silicon Wafer
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Future Developments in
Processing & Storage
• Moore’s Law
– Gordon Moore predicted the number of transistors
on a silicon chip will double every 18 months
– It has held up since the 1960s!
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The System Unit: The Basics
• The CPU
– Older CPUs processing speeds are in
MegaHertz
• 1 MHz = 1 Million ticks per second
– Current CPUs processing speeds are in
GigaHertz
• 1 GHz = 1 Billion ticks per second
– The faster a CPU runs, the more power it
consumes, and the more heat it generates
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Secondary Storage, Primary
Storage and the CPU
Secondary Storage
(Disk)
CPU
Load
Main Memory
(RAM)
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Execute
How Memory Works: RAM,
ROM, & Flash
• Types of memory chips:
1. RAM - Random Access
Memory, used to temporarily
hold software instructions
and data
2. ROM
3. Flash
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How Memory Works: RAM,
ROM, & Flash
• Types of memory chips:
1. RAM
2. ROM - Read-Only Memory, which cannot be
written on or erased by the computer user.
Contains fixed start-up instructions
3. Flash
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How Memory Works: RAM,
ROM, CMOS, & Flash
• Types of memory chips:
1. RAM
2. ROM
3. Flash - can be erased and reprogrammed
more than once
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Bits & Bytes
•
•
•
•
•
Kilobyte
Megabyte
Gigabyte
Terabyte
Petabyte
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Binary Coding Schemes
• ASCII
• EBCDIC
• Unicode
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Microchips
•
•
•
•
•
Microprocessors
Memory
Logic
Communications
Graphics
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Central Processing Unit
Control Unit
Arithmetic/Logic Unit
Registers
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CPU
CU
ALU
Registers
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Control Unit
Controls
step-by-step operation of
computer
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Arithmetic/Logic Unit
Arithmetic
2+4=6
10 - 6 = 4
Logic
9>6
3<7
5=5
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Registers
• Temporary storage locations within the
CPU
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CPU Operation
Machine
Cycle
Time it takes to process one machine
instruction
Two
parts:
• Fetch Cycle - Get instruction, decode it, set up
• Execution Cycle - Carry out the instruction
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CPU
TOTAL = 13 + 12
CU
ALU
Registers
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CPU
TOTAL = 13 + 12
ADD
CU
ALU
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CPU
TOTAL = 13 + 12
ADD
CU
ALU
13
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CPU
TOTAL = 13 + 12
ADD
CU
ALU
13
12
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CPU
TOTAL = 13 + 12
CU
ADD
ALU
13
12
25
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CPU
TOTAL = 13 + 12
CU
STORE
Main Memory
13
12
TOTAL
25
25
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ALU
Two Types of Storage
• PRIMARY Storage - Main memory or
RAM
• SECONDARY Storage - Auxiliary
Storage (disks, Flash etc.)
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Disk Drives
Drive A:
“Floppy” DRIVE
Drive C:
Hard Drive
(Internal)
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Secondary Storage Devices
Hard Disks
• Nonremovable disks
– Known as a fixed disk
– Capacity up to 1 terabyte +
– Consists of 4 - 3.5 inch metallic platters
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Hard Disk Drive
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Magnetic Disk Uses
Direct Access
1
5
6
3
2
4
7
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Magnetic Disk Storage
Rotational Delay
Seek Time
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Disk Heads
Read/Write
Head
Hair
Dust
Magnetic Disk Surface
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Head Crash
Read/Write
Head
Disk Surface
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Compact Disk (CD)
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Secondary Storage Devices
Optical Disks
• CD – compact disk
–
–
–
–
about 700 megabytes
CD-ROM
CD-R
CD-RW
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Secondary Storage Devices
Optical Disks
• DVD – digital video disk
– 4.7 – 17 gigabytes
– DVD-ROM – read-only
– DVD-R – rewritable one time
– Reusable types
• DVD-RW
• DVD-RAM
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Flash Memory
Flash memory is nonvolatile
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Input and Output
INPUT
- We provide the DATA to
be processed
OUTPUT
- We use the
INFORMATION produced
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Input & Output Hardware
Input hardware
Translates words, numbers, sounds, and
pictures into numbers
Output hardware
Translates numbers back into words, numbers,
sounds, and pictures
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Some Input Devices
• Keyboards
• Pointing devices
•
•
Mouse
Trackball
• Touch screen
• Pen input
• Source data-entry devices
•
•
•
•
•
•
Scanner
Text (OCR)
Voice
Video
MICR
FAX
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Input Hardware
• Keyboards: convert letters, numbers, and
characters into electrical signals
– English keyboards differ from foreign language
keyboards
German Keyboard
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Input Hardware
Webcams and Video-input Cards
• Webcams
– Video cameras attached to a computer to
record live moving images then post them to
a website in real time
– Require special software, usually included
with the camera
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Input Hardware
Camera Phones
• Digital cameras are now on cell phones
– Convenience of being able to take photos,
then instantly email or message them to
someone else
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Touch Screen
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Input Hardware
Source Data-Entry Devices
• Scanning devices – imaging systems
• Scanning devices – bar code readers
– Magnetic-ink character recognition (MICR)
– Optical-mark recognition (OMR)
– Optical character recognition (OCR)
• Scanning devices – fax machines
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Check Processing
9999999
12345687
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Source Data-Entry Device
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Bar Code
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Smart Cards
Similar to credit cards
Contain a microprocessor
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Digital Camera
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GPS
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Biometrics
• Fingerprints
• Retina Scanning
• Face Recognition
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Output Hardware
• Softcopy
– Data that is shown on a display screen or
is in audio or voice form; exists
electronically
– Output that is ephemeral in nature
• Hardcopy
– Printed and film output
– Output that is more permanent in nature
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Display Screens
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Resolution
..................................
Resolution = TOTAL PIXELS
= # dots across by # dots down
Example: 1024 X 768
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Types of Terminals
• Dumb Terminals
• Intelligent Terminals
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Specialized Terminals
ATM’s
POS’s
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MIDI Music
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Output Hardware:
Hardcopy Devices
• Impact printers
– Dot-matrix
• Nonimpact printers
– Laser
– Ink-jet
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Other Types of Output
•
•
•
•
•
Projectors
COM
Machine Control
Voice
House Control Center
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Machine Control
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Health Matters
• Repetitive stress injuries
– Carpal tunnel syndrome
•
•
•
•
Eyestrain & headaches
Back & neck pains
Electromagnetic fields
Noise
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Ergonomics
• Fitting the job
environment to the
worker
• Purpose – make
working conditions
and equipment safer
and more efficient
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Ergonomic Considerations
•
•
•
•
•
•
Chair
Keyboard Height
Wrist Rest
Monitor Height
Lighting
Noise
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Ergonomic Keyboard
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Ergonomics
• Eye strain
• Radiation
• Glare
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Ethics
• Theft
• Counterfeiting
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Craig’s List
72
Web Expressions