3: Input, Output and Storage Flashcards
What is an input device?
Any device that allows you to pass information from the outside world into a computer system
give 5 examples of input devices
webcam, keyboard, mouse, scanner, microphone
What is an output device?
Any device that can take data stored in digital form and convert it into a format that can be processed by humans such as sound, images or vibrations
Give 4 examples of output devices
speakers, headphones, monitors, printers
What is a storage device?
Any device used for either temporary or permanent storage of data - can be internal or external
Give 3 examples of internal storage devices
RAM, SSD, magnetic hard drive
Give 3 examples of external storage devices
Optical disk such as DVD or Blu-ray, USB stick, memory card
What is a drive?
A device that reads and writes data from secondary storage
What is the media?
What the data is actually stored on
What are 5 types of media for optical devices?
- Compact Disk Read only (CDR)
- Compact Disk Read Write (CDRW)
- Digital Versatile Disk Read only (DVDR)
- Digital Versatile Disk Read Write (DVDRW)
- Blu-ray
How do optical drives work?
- A laser is shone at the media and processing the reflection from the media
- In read only drives, the surface of the disk is physically burned by the laser, creating what are known as pits and lands, suitable for storing 0s and 1s. Once the media is burnt, the surface cannot be changed
- For writable drives, the chemical composition of the disk is changed by a reversible chemical reaction. This means the data can be written many times
what are the positives of optical devices?
- cheap
- lightweight
- portable
What are the negatives of optical devices?
- slow access times
- prone to scratches
What are the positives of magnetic storage?
- cheap
- large capacity
What are the negatives of magnetic storage?
- slow access times
- fragile
Why is magnetic storage slower than the alternatives?
- contains a drive head, which has to physically move across the surface of the disk
- since it is a mechanical component, it will eventually fail, and it will run a little slower than alternative drives with no moving parts
What are the positives of SSDs?
- durable
- fast access times
What are the negatives of SSDs?
- cost
- limited read/writes
How do SSDs work?
- Flow of electricity forcing electrons into floating gates between two oxide layers
- This causes a change in the charge between the floating gate which can be measured as a 0 or a 1
Why do SSDs only have a limited lifespan?
- Over time, the oxide layers will deteriorate, making the transfer of electrons unreliable
- this gives SSDs a limited number of read/write cycles and therefore a limited lifespan
What is virtual storage (cloud storage)?
The concept of storing and retrieving data over the internet in the cloud instead of a local storage device
What are the advantages of virtual storage?
- data can be accessed any time from any device as long as there is internet access
- data can easily be shared without the need for removable media transfer (e.g USB drive)
- easy to collaborate
- Storage considered to be ‘limitless’ from the users point of view
What are the disadvantages of virtual storage?
- Can become quite expensive
- If connectivity is poor, access times can be slow
- no internet connection means no access to your files
What is ROM?
- Small pieces of Read Only Memory, located on the motherboard
- non volatile
- contains very first instructions for the computer (bootstrap)
What is RAM?
- Temporary storage of instructions and data
- Holds information being executed by the processor
- Volatile
- Much faster than hard disk
How does ROM help the computer start functioning when it is first turned on?
- It contains the bootstrap, a set of initial startup instructions placed in the ROM during manufacturing
- These first initial instructions perform a Power On Self Test (POST)
- The POST sends signals to all connected components and makes the CPU aware of their existence
- After this, it can open the OS into RAM
- The OS can then begin the booting up process
