Transcript ITS_3_Review of Storage, Display, and Input Devices

Review of Storage,
Display and Input
Devices
Written by: Andrea LeShea
Georgia CTAE Resource Network 2010
Storage Devices
 Used to keep data when the
power to the computer is turned
off.
 Medium/media
 Location where data is stored.
Hard Disk
 Usually mounted inside the
computer’s system unit.
Magnetic Storage
 Recording of data onto
disks or tape by
magnetizing particles
of an oxide based
surface coating.
Floppy Disk
 Round piece of flexible
Mylar plastic covered
with a thin layer of
magnetic oxide and
sealed inside a protective
covering
 May be referred to as a
“floppy”
 3½ disk capacity is 1.44
MB or 1,440,000 bytes
Optical Storage
 Means of recording data as light and dark spots on CD
or DVD.
 Reading is done through a low-power laser light.
 Pits

Dark spots
 Lands

Lighter, non-spotted surface areas
CD-ROM
 “CD – Read Only Memory”
 Also called CD-R
 CD-Read
 Storage device that uses laser
technology to read data that is
permanently stored on
compact disks, cannot be used
to write data to a disk.
CD-RW
 “CD-Read Write”
 A storage device that reads data from CD’s and also can write
data to CD’s.
 Similar to a CD-ROM, but has the ability to write to CD.
DVD
 DVD ROM
 Digital Video Disk which is read only.
 DVD-R
 Digital Video Disk which can be written to one time. It
then becomes read only.
 DVD-RW
 Digital Video Disk which can be rewritten to.
Blu-Ray Technology
 New standard in storage
 Blu-Ray
 New disks use blue laser light instead of the red laser
light used in traditional CD players.
 Disks may ultimately hold


Over 30GB on one-sided disks.
Over 50GB on two-sided disks.
Flash or Jump Drives
 External storage devices that can be used like a
external hard drive.
 They have the capability to be saved to, deleted from,
and files can be renamed just like with a normal hard
drive.
List of Devices for Secondary
Storage
 Magnetic tape and disks
 Compact Disk Read-Only Memory (CD-ROM)
 Write Once Read Many - (WORM)
 Magneto-optical disks
 Redundant Array of Inexpensive Disks (RAID)
 Optical disks
 Digital Video Disks
 Memory cards
 Flash memory
 Removable storage
Monitor Overview
 Display device that forms an image by converting
electronic signals from the computer into points of
colored light on the screen.
 The most-used output device on a computer.
 Most desktop displays use a cathode ray tube (CRT).
 Laptops use liquid crystal display (LCD), lightemitting diode (LED), and gas plasma or other image
projection technology.
 Monitors using LCD technologies are beginning to
replace CRT.
LCD Technology
 Used for displays in notebooks, small computers,
pagers, phones and other instruments.
 Uses a combination of fluorescent-based backlight,
color filters, transistors, and liquid crystal to create
and illuminate images.
 In 1997, manufactures began to offer full size LCD
monitors as alternatives to CRT monitors.
 Until recently, was only used on notebook computers
and other portable devices.
How Monitors Work
 Most use a cathode-ray tube as
a display device.
 CRT: Glass tube that is narrow
at one end and opens to a flat
screen at the other end.
 Narrow end contains electron
guns.
 Single gun for monochrome and
three guns for color.
 Display screen is covered with tiny
phosphor dots that emit light
when struck by the electron gun.
Monitor Quality, Resolution and Pixels
Quality:
 Manufacturers describe quality by dot pitch.
 Smaller dot pitches mean pixels are closely spaced
which will yield a sharper image.
 Resolution:
 Indicates how densely packed the pixels are.
 The amount of Pixels on the screen. The more pixels
the better the resolution.
Pixels:
 The smallest unit in a graphic image; computer
display devices use a matrix of pixels to display text
and graphics.
Input Devices
 Units that gather
information and
transform that
information into a
series of electronic
signals for the
computer.
Mouse
 An input device that allows
the user to manipulate
objects on the screen by
moving the mouse along the
surface of the desk.
Keyboard
 An arrangement of letters,
numbers, and special function
keys that act as the primary input
device to the computer.
Scanner
 Light sensing input device that reads printed text and
graphics and then translates the results into a form the
computer can process.
 Allows users to capture data from an original source
document and save in an electronic format.
Touch Screen
 A touch sensitive display device that allows users to
interact with devices by touching various areas of the
screen.
 Examples of Touch Screens:
 Smart Phones
 Airport Check-In Kiosk
 Grocery Store Self Check Out
 ATM’s
Barcode Reader
 A barcode reader (or barcode scanner) is an
electronic device for reading printed barcodes. Like a
flatbed scanner, it consists of a light source, a lens and
a light sensor translating optical impulses into
electrical ones.
Pointing Device
 An input device that allows a user to control a pointer
on the screen.
 The location and shape change as the user moves the
pointing device.
 Pointing Devices Include:
 Mouse
 Trackball
 Touchpad
Digital Camera
 Allows users to take pictures and store images
electronically.
Smart Phone
 A small hand held device that users
can enter data and instructions
using a variety of techniques.
References
 Computing Essentials 2005
 M. Guymon. Pleasant Grove High School