Transcript Information Processing

Information Processing
Lecture
A
2
Peripherals
Objectives For Week 2
After studying this week’s work, you should have:
• examined the different types of peripherals that
can be used to augment a computer system, and
understood how some of these function.
• collaborated with others, in order to research and
present a topic, and acquired knowledge about
how to present information more effectively.
• engaged with some of the social and ethical
issues related to the use of computers.
Peripherals
• These are devices other than the main
processor board and memory
• Three categories:
– Input
– Output
– storage
Input Peripherals
•
•
•
•
•
Keyboard
Mouse
Touch Screen
Joysticks
…and?
Input Peripherals
•
•
•
•
•
•
•
•
Speech Input Device
Digital Camera
Video Camera
Graphics Tablet
Pen-Input
Tracker Balls
OMR
… and many more
Output Peripherals
•
•
•
•
VDU
Plotters
Printers
… Others?
Storage
• Primary Storage
– Internal
(RAM/ROM etc.)
• Secondary Storage
– Peripheral devices
Data Sizes
•
•
•
•
•
•
•
Bit
Nibble
Byte (= 8 bits)
Kilobyte (~ 1024 B)
Megabyte ( 1024K)
Gigabyte (1024 Mb)
Terabyte (1024 Gb)
NB
1024 = 210
Secondary Storage
Criteria:
• Capability
– Size
– flexibility
• Integrity of Data
• Cost
• Speed
Storage Devices 1
Floppy Disks
•
•
•
•
•
Circular plastic coated with magnetic layer
360k to 2.33 Mb
Once industry standard
Replaced by CD-ROM
Formatting:
– Double-sided
– Tracks (concentric circles)
– Sectors (sections of tracks)
Storage Devices 2
Hard Drives
• Stack of magnetically coated rigid disks
(platters)
• Hermetically sealed unit
• Disks are subdivided into tracks, sectors
etc.
Storage Devices 3
Optical Drives
•
•
•
•
CD-ROM , DVD
Single spiral track
Divided into sectors
CD: 240 tracks per cm approx.
CD Standards
• CD (CD-DA)
–
–
–
–
“Red Book”
Designed for music
Allows for text
72 mins of hi-fi sound
• CD-ROM
– “yellow Book”
– Accepted standard
• CD-I
– “Green Book”
– Interactive
– Own operating system
Tape Storage
•
•
•
•
Sequential Access Devices
Reel to reel
Digital Audio Cartridges
Able to store Mb, Gb, Tb of data.
Discussion
•
•
•
•
•
Offer brief descriptions of how you think
the following peripherals work:
A Keyboard
A Mouse
A Bar-Code Reader
A Scanner
A Laser Printer
What have we covered?
• Peripherals
• Storage Devices
Further information on how computer hardware
functions can be found at:
http://howstuffworks.com