inPUT OUTPUT AND STORAGE Flashcards
what does a input device do?
Input data is raw fata, by processing it we give it meaning and can complete the associated task
Examples of input devices
Mouse Camera keyboard
examples of accessibility input devices
Braille keyboard, eye tracker , microphone
What does a output device do?
Takes processed data and interprets it to present for a user.
examples of output devices
monitor, printer , speaker
example of accessibility output devices
Braille Embosser
What are the primary storage devices
RAM/CACHE/ROM
What are the pros and cons of primary memory`
Very fast/ close to the CPU
Volatile - loses contents when no power
What does RAM do?
RAM is used to store currently running programs and data
What are secondary storage devices?
Magnetic Hard Disk Drive / SSD / CD / DVD
What are the pros and cons of secondary storage
- Slower read/write speeds than primary memory
- non-volatile - retains it’s contents when there is no power
What is the purpose of secondary storage
- To store the OS
- To store programs and data whilst not in use
What are the different types of secondary storage
Optical / Magnetic / Solid State
How does Optical storage work?
Uses a laser to read pits and lands by reading the reflection.
Large volumes can created quickly and they are lightweight and cheap - making them perfect for distributing music / games / software / films
What are the Pros and cons of optical storage?
- Lightweight
- cheap
- portable
- easy to scratch
- slow read / write
How does Magnetic storage work?
Uses polarity to ‘read’ and ‘write’ magnetism to a disk/tape
a HDD has a read-write head that is very close to the fast spinning platters - makes it delicate
What are the Pros and cons of magnetic storage?
- Price per GB is very cheap
- Large Capacity
Fragile
Mechanical - Will eventually fail
how does solid state memory work?
uses logic gates to store 1s and 0s (many NAND gates)
No moving parts therefore more durable and less power required
what are the prose and cons of SSD
- Very fast read/write speeds
- Durable and lightweight
- in general more expensive per GB the HDD
- limited number of read/writes
What is Virtual Storage
When data/files are physically stored on a computer (server) in another location, accessed via a network.
Such as n: drive at collage. Or Google Drive
What is Virtual Memory
When free space in RAM is low. The OS can use your HDD / SSD as virtual Memory (a bit like RAM).
Parts of currently running programs might be transferred to Virtual memory to free up some space
if the pages in virtual memory are needed by the CPU they need to be transferred back to RAM first.
Virtual Memory slows down your computer but, at least it doesn’t crash
what are the pros and cons of virtual storage
- Can store a lot of data (perhaps more than you could on your computer)
- Can access your files from any location
- Can share / collaborate on a document
- Might incur a cost
- Security /backup you are trusting another company to look after your data and not get hacked
- relies on a connection with enough bandwidth
What is ROM
Read only memory.
A computer might use ROM to store the Bootstrap program.
A small program that helps to get your OS loaded from Secondary Storage when you first turn on your computer
-its non-volatile
some embedded computers might only have ROM and secondary storage. As they only need to load their programs and these programs never change.
