Input / Output Devices

Question 1

What does a Barcode Laser Scanner do

Answer 1

This is what you see in a supermarket
- laser is slowly dragged across the barcode
- laser is reflected off moving mirror
- barcode can be translated into digital format
- thic can then be coded and looked up

Question 2

What does a digital camera do

Answer 2

• Shutter opens
• Light enters the camera
• An image is processed onto the sensor at back of lens
• Each sensor measure the brightness of each pixel
• This is turned into an electrical signal
• Which is stored as binary
• The digital recreated image is greyscale

Question 3

What does a Laser printer do

Answer 3

• Powdered ink (toner) is stored in cartridges
• Print software generates a bitmap image of what is being printed
• The drum is negatively charged
• The laser light causes the areas of the drum it hits to lose their negative charge
• Drum rotates past toner cartridges
• Charged particles of toner are attached to areas of page which have not been lasered.
• Particles on page are then bonded to the page with heat and pressure.

Question 4

What does RFID do

Answer 4

• RFID tags store information
• Can be read without being in sight
• Can be read from upto 300 metres away
• Can pass stored data from the tag to the receiver
• Consists of a microchip at the centre
• And an antenna for communication

Question 5

Characteristics of Optical Storage

Answer 5

CD, DVD, Blu-Ray

Low capacity
Slow to access data
Thin, lightweight and portable

Question 6

Characteristics of magnetic storage

Answer 6

Hard Disk Drive

High Storage Capacity
Quick to access data
Has moving parts, which eventually fail
Hard disks perform better if they are defragmented

Question 7

Characteristics of Solid State Storage

Answer 7

SSD, USB sticks

Medium storage capacity
Very quick to access data
No moving parts so very reliable
No noise
Low power
No need to defragment
Low number of read/write cycles
Expensive