Storage, Input and Output Devices

Question 1

How does magnetic storage work?

Answer 1

An actuator arm with a magnetic field magnetises and demagnetises segments of a metal disk, which are then detected to convert back to binary. Magnetisation represents a “1”.

Question 2

Secondary storage (definition)

Answer 2

Non-volatile storage of all programs that the computer uses once booted; stored as 1s and 0s

Question 3

Advantages of magnetic storage (3)

Answer 3

Moderate price per unit storage, cheaper at high capacities than alternatives

High capacities of 500gb -TBs

Last 3-5 years if well-kept

Question 4

Disadvantages of magnetic storage (2)

Answer 4

Not portable due to delicate moving parts

Not durable and become highly unreliable with age

Question 5

How does optical storage work?

Answer 5

A laser is used to engrave marks onto the plastic coating of a disk. Read by running a light over the disk and noting reflections, where engraved parts = little reflection = 0

Question 6

What are the types of optical storage? How are they different?

Answer 6

CDs, DVDs, and Blu-ray, all of which can be R or RW.
DVDs and Blu-ray can be double sided.

Question 7

Advantages of optical storage (3)

Answer 7

Highly portable

Very cheap

Reliable for a long time if kept well

Question 8

Maximum capacities of optical storage types

Answer 8

Low maximum capacity
CD = 640MB
DVD = 4-8GB per side
Blu-ray = 25GB per side

Question 9

Disadvantages of optical storage (3)

Answer 9

Low maximum capacity

Easy to scratch and damage

Slow access speeds

Question 10

How does flash storage work?

Answer 10

Contains rows of transistors in series that can conduct current and store charge to mean a 1 or 0

Question 11

How does cloud storage work?

Answer 11

Data is stored off-site by a third-party provider and users can upload/download their stored data using the internet.

Question 12

Advantages of cloud storage (4)

Answer 12

• Easily get more space without transferring data
• Moderately cheap per unit of storage
• Data security/management included
• Data can be accessed on any computer with access to the cloud

Question 13

Disadvantages of cloud storage (2)

Answer 13

• Only accessible with internet connection
• Relies on third-party to secure data and continue to store it

Question 14

How does a keyboard work?

Answer 14

It has buttons on it, each one with a different character. Each key sends a signal to the computer telling the computer what key it is. The computer interprets that depending on what software it is running.

Question 15

How does a touchscreen work?

Answer 15

Responds to contact to allow user to interact with the interface through the screen, using the position of contact to work out what command has been made. Used in combination with a graphical interface for easy use.

Question 16

How does a capacitive touchscreen work?

Answer 16

Display is made up of tiny wires that complete a circuit whenever anything with an internal current (e.g. Human hand) touches them. Capacitive screens can also respond to multiple contact points at once.

Question 17

How does a microphone work?

Answer 17

Detects sound waves hitting an internal diaphragm and records their amplitude as the nearest binary equivalent on a predetermined scale each second (e.g. Taking a measurement 10 times per second). Sound is stored as binary along with metadata on how to recreate it (e.g. What binary equivalent each amplitude is)

Question 18

How can sound quality from a microphone be increased?

Answer 18

Using more bits to represent amplitude or taking more measurements per second means more variations can be recorded, making a more accurate representation of the sound. However, this increases file size significantly as well

Question 19

How does a printer work?

Answer 19

Uses lasers and special powder, or a method of spraying ink to make shapes on the page.

Question 20

How does a monitor work?

Answer 20

Uses tiny LEDs in rows to display graphics information generated by the computers.

Question 21

How is colour represented on a monitor?

Answer 21

Binary is used to represent the colour and brightness of each pixel (More binary per pixel = larger range of colours are able to be represented). Most screens take values for red, green, blue and black to create colours.

Question 22

How does a speaker work?

Answer 22

Uses electromagnets to vibrate a coil depending on electronic signal provided. The vibration then generate sound waves. Sound is represented in binary and the processor will give the speaker instructions on how to interpret it

Question 23

How do noise cancelling headphones work?

Answer 23

Noise cancelling headphones detect incoming sound waves and use a speaker produce a wave of the same frequency but opposite phases, cancelling out the wave due to principle of superposition