SLR 3 - INPUT, OUTPUT AND STORAGE Flashcards
What is an input device?
any device that allows you to pass info from the outside world into a computer system
What are some examples of input devices?
- keyboard
- mouse
- webcam
- barcode scanner
- microphone
What is an output device?
any device that can take data stored in digital form and convert it to another format that humans can process (eg: sound/images)
What are the 3 types of secondary storage?
- magnetic drives
- optical drives
- solid state drives
What is a magnetic drive?
- uses minute magnetic particles or ‘domains’ to store data.
- hard disk is an example of a magnetic storage device. it contains several platters on a spindle, spinning at high speed, with read/write heads floating just above the surface.
- another example of magnetic storage is a magnetic tape cartridge.
Advs of magnetic storage
- huge capacity, offers up to several terabytes per device
- low cost per gigabyte - magnetic tape is the cheapest, but hard disk is very low as well
- hard Disk offers high speed data access
- magnetic tape can hold its data for up to thirty years in the correct environment
Disadvs of magnetic storage
- not as portable as other technologies. But external hard disks are commonly available, but they need to be treated carefully
- slow due to moving parts
- not robust due to moving parts
What is optical storage?
- includes CD, DVD and Blu-ray disks.
- a laser beam burns pits on to the surface of the optical disk. If a pit is present, this can represent a data bit being ‘1’ and if no pit is present, this can represent a data bit being ‘0’
Advs of optical storage
- relatively cheap
- very portable compared to hard disk
- ideally sized for storing movies and videos
Disadvs of optical storage
- low capacity
- slow to write (burn) to and much slower than hard disk to access
- easily scratched
What is solid state storage?
- solid state media includes USB memory sticks, Solid State Drives and SDHC memory cards (as found in digital cameras)
- solid state media hold data using electronic switches. If the switch is open, it represents a ‘1’, since it retains an electric charge. If it is closed, it represents a ‘0’. It is an electrical form of storage, unlike magnetic or optical media. The technology is called ‘Flash memory’
Advs of solid state storage
- very portable in the form of SD memory cards and USB memory sticks
- large capacity, especially in the form of a solid state drive
- robust
- very fast
Disadvs of solid state storage
- expensive
- limited number of read/write cycles
What should be considered when choosing the most suitable storage media?
- capacity
- speed
- portability
- durability
- reliability
- cost
What are the 2 types of primary storage?
- RAM
- ROM
What is RAM?
- Random Access Memory
- temporary storage of instructions and data
- holds info being executed by processor
- stores OS
Is RAM volatile/non-volatile and what does this mean?
- RAM is volatile
- volatile memory is a type of memory that loses its data once power to the memory chip is switched off or interrupted
What is ROM?
- Read Only Memory
- stores key instructions that must not be lost/overwritten (eg: bootstrap (computer start-up instructions)
Is ROM volatile/non-volatile and what does this mean?
- non-volatile
- it keeps its data even when there is no power supply
What is virtual storage/cloud storage?
- the concept of storing and retrieving data over the internet in the cloud instead of on a storage device
- can also refer to abstraction/separation of logical storage from physical storage
Advs of virtual storage
- data can be accessed at any time from any device as long as there is internet access
- data can be easily shared without the need for removable media transfer
- easier to collaborate
- storage considered limitless from users POV
Disadvs of virtual storage
- can become quite expensive
- if connectivity is poor, access times can be slow
- no internet connection means no access to files
When data is stored virtually where is it actually stored?
all data is actually stored on physical permanent storage media in a remote location
