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


Basic Hardware Components of a Computer

• Input devices

• Central Processing Unit (CPU)

• Memory

• Storage devices

• Output devices

At the desktop


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)


CPU (Central Processing Unit)

• Interprets and executes the instructions in each program

• Supervises arithmetic and logical data manipulations

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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)


Memory

ROM (read-only memory)

• Information is stored permanently on a chip

• Contains startup instructions and other permanent data


Buses

Information travels between components on the motherboard through groups of wires called system buses, or just buses


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


A Computer Truism

• A computer system’s throughput speed

can be no faster than its slowest

component.


Computer Families

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Supercomputers

For those who need access to the fastest, most

powerful computers made.

Many scientific and research applications.


Mainframes

Used by large organizations, such as banks and airlines, for big computing

jobs


Servers

Computers designed to provide software and

other resources to other computers over a

network


Workstations

High-end desktop computers with massive

computing power

used for high-end interactive applications like

Computer-Aided Design – Computer-Aided

Manufacturing (CAD-CAM).


PCs and Macs

Serve a single user at a time


Portable Computers

Machines that are not tied to the desktop

• Notebooks (laptops)

• Handheld computers (PDAs)

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Embedded Computers

Special-purpose computers that perform

specific tasks, e.g.

• Sensing your toast is done

• Monitoring your heart rate


Storage Devices/Media

Data Repositories


• Magnetic

• Optical

• Solid-state


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


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


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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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


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


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


Peripherals


Digital

Peripherals perform the translations

AnalogAnalogAnalogAnalog


Peripherals

• Input devices

• Output devices

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Input Devices

• Text entry

• Pointing

• Scanning

• Digitizing

• Sensing


Input Devices - Text

Keyboard

• The most familiar input device

• Used to enter letters, numbers and special characters


Keyboards• Standard keyboard • Ergonomic keyboards

• To address possible medical problems • Wireless keyboard• Folding keyboards

• Used with palm-sized computers• One-handed keyboards• Membrane keyboards


Input Devices - Pointing

• Mouse • Touchpad • Pointing stick • Trackball • Joystick • Graphics tablet • Touch screen

With Stylus


Input Devices – Scanning

• Reads marks representing codes specifically

designed for computer input


Input Devices - Digitizing

• Scanner• Tablet PC • Smart whiteboard

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• Digital camera• Snapshots captured as digital images

• Digital images stored as bit patterns on disks or other digital storage media



• 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



• 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


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


Sensing - The EyegazeTM

system


Output Devices

For human senses

– Vision

– Hearing - Sound

– Haptic – Touch

Other devices

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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


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



Monitor size:

• Measured as a diagonal line across the screen



• 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


Color depth - Examples

1-bit depth

16-bit depth8-bit depth

4-bit depth


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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Output - Paper

• Printers (vision)

• Plotters (vision)

• Embossers (haptic)


Output Devices - Printers


Plotter

can produce large, finely scaled engineering blueprints and maps


Embosser

Creates Braille output


Haptic - Refreshable Braille display


Sound Production

• Speakers

• Headphones

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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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