I/O and Storage (1.1.3) Flashcards
What is an input device?
A device used to put data and information into a computer.
What is an output device?
A device used to send information from the computer.
4 input device examples
Keyboard, webcam, magnetic stripe reader, barcode readers
3 output device examples
Speakers, printers, projector
What are the three main types of secondary storage?
- Optical
- Magnetic
- Flash
What is optical storage?
Data is read and written with lasers. Pits scatters light (representing a 0), lands reflect light (representing a 1)
3 types of optical storage
Smallest size -CD (compact disc)
-DVD (digital versatile disc)
Biggest size (5x DVD) -Blu-ray
Optical ADVS
-Small, thin and light= very portable
Optical DISADVS
- Easily scratched
- Relatively low storage
- Slow
How does magnetic storage work?
Magnetic material is either polarised or unpolarised which can represent a 1 or 0. If an area is polarised the poles align and can be read by a read/write head, if not they are randomly scattered and produce a different reading.
3 magnetic storage devices
- Hard Disk Drives
- Magnetic tape
- Floppy disks
Features of a HDD:
- high capacity (500gb to 5tb)
- use rotating magnetic platters under a read/write arm
HDD DISADVS
- Slow
- Can easily be damaged by movement
What is flash storage?
A fast and compact storage which uses silicon semiconductors which form logic gates to give a binary output.
Flash memory tends to be more expensive than other forms of storage.
Flash memory examples
- SSD
- USB drive
- Memory cards
SSD ADVS
- Light and portable
- No moving parts: more resistant to damage
- High speed
SSD DISADVS
- Most expensive
- Limited number of times it can be written to
Two types of primary storage?
- RAM
- ROM
What is the main memory?
A data store that can be directly addresses by the CPU and stores program instructions and data.
What is RAM?
Random access memory is a fast, volatile main memory used to store data and programs that are currently being used
What is ROM?
Read only memory cannot be modified and stored core instructions such as the bootstrap routine to load the OS. It is non-volatile meaning its contents remain when turned off.
What is virtual storage?
Storing information remotely e.g. in the cloud or on a network
It is an abstraction of multiple drives acting as one
Virtual storage ADVS
Convenient to access and share
Virtual storage DISADVS
Limitations of network speed
High cost
