basic hardware components of a computer at the desktop · • the instructions that tell hardware...
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Hardware
Session 2
CSC200 Survey of Computing
Copyright M J Davidson 2008
A computer's capabilities and
versatility are built upon its:
• Hardware: • The physical part
• Software: • The instructions that tell hardware how to transform
the input data into the necessary output
• Connections: • Its ability to communicate with other computers
Copyright M J Davidson 2008
Basic Hardware Components of a Computer
• Input devices
• Central Processing Unit (CPU)
• Memory
• Storage devices
• Output devices
At the desktop
Copyright M J Davidson 2008
CPU and Memory
• CPU communicates with all the other parts of the computer system indirectly through memory
• Housed along with other chips and electronic components on the motherboard
• (pg 50 of TT)
Copyright M J Davidson 2008
CPU (Central Processing Unit)
• Interprets and executes the instructions in each program
• Supervises arithmetic and logical data manipulations
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Copyright M J Davidson 2008
Memory RAM
(random access memory)
• Used to store program instructions and data temporarily
• Unique addresses and data can be stored in any location
• Can quickly retrieve information
• Will not remain if power goes off (volatile)
Copyright M J Davidson 2008
Memory
ROM (read-only memory)
• Information is stored permanently on a chip
• Contains startup instructions and other permanent data
Copyright M J Davidson 2008
Buses
Information travels between components on the motherboard through groups of wires called system buses, or just buses
Copyright M J Davidson 2008
Factors that Impact CPU Performance
•Its internal clock speed
• Measured in units called gigahertz (GHz)billions of clock cycles per second
•The architecture and word size of the processor
•Word size
• Number of bytes that a CPU can process at one time
Copyright M J Davidson 2008
A Computer Truism
• A computer system’s throughput speed
can be no faster than its slowest
component.
Copyright M J Davidson 2008
Computer Families
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Copyright M J Davidson 2008
Supercomputers
For those who need access to the fastest, most
powerful computers made.
Many scientific and research applications.
Copyright M J Davidson 2008
Mainframes
Used by large organizations, such as banks and airlines, for big computing
jobs
Copyright M J Davidson 2008
Servers
Computers designed to provide software and
other resources to other computers over a
network
Copyright M J Davidson 2008
Workstations
High-end desktop computers with massive
computing power
used for high-end interactive applications like
Computer-Aided Design – Computer-Aided
Manufacturing (CAD-CAM).
Copyright M J Davidson 2008
PCs and Macs
Serve a single user at a time
Copyright M J Davidson 2008
Portable Computers
Machines that are not tied to the desktop
• Notebooks (laptops)
• Handheld computers (PDAs)
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Copyright M J Davidson 2008
Embedded Computers
Special-purpose computers that perform
specific tasks, e.g.
• Sensing your toast is done
• Monitoring your heart rate
Copyright M J Davidson 2008
Storage Devices/Media
Data Repositories
Copyright M J Davidson 2008
• Magnetic
• Optical
• Solid-state
Copyright M J Davidson 2008
Storage - Magnetic Disks
• Random Access
• Hard Drive
• Non-removable, rigid disks that spin continuously and rapidly
• Floppy disks
• Provide inexpensive, portable storage
• Removable media (Zip & Jaz disks) • Provide high-capacity portable
storage
Copyright M J Davidson 2008
Storage – Magnetic Tape
• Sequential data access – major limitation
• Can store large amounts of information in a small
space at a relatively low cost
• Used mainly for backup purposes
Copyright M J Davidson 2008
Storage – Optical Disks
Use laser beams to read and write bits of information
on the disk surface
• Not as fast as magnetic hard disks
• Massive storage capacity
• Very reliable
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Copyright M J Davidson 2008
Optical Disks - CDs• CD-ROM
• Optical drives that read CD-ROMs
• CD-R
• WORM media (write-once, read many)
• CD-RW
• Can read CD-ROMs and write, erase and
• rewrite data onto CD-R & CD-RW disks
Copyright M J Davidson 2008
Optical Disks - DVDs
• DVD (Digital Versatile (or Video) Disks)• Store & distribute all kinds of data• Hold between 3.8 and 17 gigabytes of
information
• DVD-ROM drives
• Can play DVD movies, read DVD data disks, read
• standard CD-ROMs, and play audio CDs• Because they’re read-only, they can’t record
data, music, or movies
• DVD-RAM drives • Can read, erase, and write data (but not DVD
video) on multi-gigabyte
• DVD-R (but not CD-R or CD-RW) media
Copyright M J Davidson 2008
Storage –Solid-State Storage Devices
Contains an erasable memory chip
• Sizes range from 16 MB to 8 GB+ for flash drives
• Compact alternative to disk storage
• Contains no moving parts
• replacing disk and tape storage
Copyright M J Davidson 2008
Peripherals
Copyright M J Davidson 2008
Digital
Peripherals perform the translations
AnalogAnalogAnalogAnalog
Copyright M J Davidson 2008
Peripherals
• Input devices
• Output devices
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Copyright M J Davidson 2008
Input Devices
• Text entry
• Pointing
• Scanning
• Digitizing
• Sensing
Copyright M J Davidson 2008
Input Devices - Text
Keyboard
• The most familiar input device
• Used to enter letters, numbers and special characters
Copyright M J Davidson 2008
Keyboards• Standard keyboard • Ergonomic keyboards
• To address possible medical problems • Wireless keyboard• Folding keyboards
• Used with palm-sized computers• One-handed keyboards• Membrane keyboards
Copyright M J Davidson 2008
Input Devices - Pointing
• Mouse • Touchpad • Pointing stick • Trackball • Joystick • Graphics tablet • Touch screen
With Stylus
Copyright M J Davidson 2008
Input Devices – Scanning
• Reads marks representing codes specifically
designed for computer input
Copyright M J Davidson 2008
Input Devices - Digitizing
• Scanner• Tablet PC • Smart whiteboard
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Copyright M J Davidson 2008
Input Devices - Digitizing
• Digital camera• Snapshots captured as digital images
• Digital images stored as bit patterns on disks or other digital storage media
Copyright M J Davidson 2008
Input Devices - Digitizing
• Video digitizer
• Capture input from a:
• Video camera
• Video cassette recorder or television
• Convert it to a digital signal
• Videoconferencing
• People in diverse locations can see and hear each other
• Used to conduct long-distance meetings
• Video images transmitted through networks
Copyright M J Davidson 2008
Input Devices - Digitizing
• Microphone
• Audio digitizers
• Digitize sounds from
• Microphones
• Other input devices
• Digital signals can be
• Stored
• Further processed with
specialized software
• A digital signal
processing chip compresses the stream
of bits before it is transmitted to the CPU
Copyright M J Davidson 2008
Input Devices - Sensing
• Sensors • Designed to monitor physical
conditions
• Temperature, humidity, pressure
• Provide data used in:
• Robotics
• Environmental climate control
• Weather forecasting
• Medical monitoring
• Biofeedback
• Scientific research
Copyright M J Davidson 2008
Sensing - The EyegazeTM
system
Copyright M J Davidson 2008
Output Devices
For human senses
– Vision
– Hearing - Sound
– Haptic – Touch
Other devices
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Copyright M J Davidson 2008
Output Devices – Visual
• Monitor classes
• CRTs (cathode-ray tubes)
• LCDs (liquid crystal displays) are now more
popular
• Portable computers
• Projection
• Overhead projection panels
• Video projectors
Copyright M J Davidson 2008
Output Devices – Monitors
• A monitor or video display terminal (VDT) displays characters, graphics, photographic images, animation and video
• Video adapter—connects the monitor to the computer
• VRAM or video memory—a special portion of RAM to hold video images • the more video memory, the more picture detail is
displayed
Copyright M J Davidson 2008
Output Devices – Monitors
Monitor size:
• Measured as a diagonal line across the screen
Copyright M J Davidson 2008
Output Devices – Monitors
• Image quality is affected by resolution and color depth (or bit depth)
• Resolution: The number of pixels displayed on the screen
Pixels (or picture elements): tiny dots that compose a picture
The higher the resolution, the closer together the dots
• Color depth: refers to the number of different colors a
monitor displays at one time
Copyright M J Davidson 2008
Color depth - Examples
1-bit depth
16-bit depth8-bit depth
4-bit depth
Copyright M J Davidson 2008
Screen Resolution and Color Depth- Do try this at home
• Open a document on your computer
• Change the resolution of your monitor (via Control Panel)
• View the document again – how did it change
• Change the color depth,
• How did that impact what you view ?
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Copyright M J Davidson 2008
Output - Paper
• Printers (vision)
• Plotters (vision)
• Embossers (haptic)
Copyright M J Davidson 2008
Output Devices - Printers
Copyright M J Davidson 2008
Plotter
can produce large, finely scaled engineering blueprints and maps
Copyright M J Davidson 2008
Embosser
Creates Braille output
Copyright M J Davidson 2008
Haptic - Refreshable Braille display
Copyright M J Davidson 2008
Sound Production
• Speakers
• Headphones
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Copyright M J Davidson 2008
Controlling Other Machines
Output devices take bit patterns and turn them into non-digital movements
• Robot arms
• Telephone switchboards• Transportation devices• Automated factory equipment
• Spacecraft• Force feedback joystick
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