Storage, Input and Output Devices Flashcards
How does magnetic storage work?
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”.
Secondary storage (definition)
Non-volatile storage of all programs that the computer uses once booted; stored as 1s and 0s
Advantages of magnetic storage (3)
Moderate price per unit storage, cheaper at high capacities than alternatives
High capacities of 500gb -TBs
Last 3-5 years if well-kept
Disadvantages of magnetic storage (2)
Not portable due to delicate moving parts
Not durable and become highly unreliable with age
How does optical storage work?
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
What are the types of optical storage? How are they different?
CDs, DVDs, and Blu-ray, all of which can be R or RW.
DVDs and Blu-ray can be double sided.
Advantages of optical storage (3)
Highly portable
Very cheap
Reliable for a long time if kept well
Maximum capacities of optical storage types
Low maximum capacity
CD = 640MB
DVD = 4-8GB per side
Blu-ray = 25GB per side
Disadvantages of optical storage (3)
Low maximum capacity
Easy to scratch and damage
Slow access speeds
How does flash storage work?
Contains rows of transistors in series that can conduct current and store charge to mean a 1 or 0
How does cloud storage work?
Data is stored off-site by a third-party provider and users can upload/download their stored data using the internet.
Advantages of cloud storage (4)
- 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
Disadvantages of cloud storage (2)
- Only accessible with internet connection
- Relies on third-party to secure data and continue to store it
How does a keyboard work?
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.
How does a touchscreen work?
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.
How does a capacitive touchscreen work?
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.
How does a microphone work?
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)
How can sound quality from a microphone be increased?
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
How does a printer work?
Uses lasers and special powder, or a method of spraying ink to make shapes on the page.
How does a monitor work?
Uses tiny LEDs in rows to display graphics information generated by the computers.
How is colour represented on a monitor?
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.
How does a speaker work?
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
How do noise cancelling headphones work?
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
