Storage Devices Flashcards
Magnetic storage how it works
Tiny places are magnetised and those magnetised areas are 1
3 types of storage media
magnetic, optical, solid-state
Hard disk drive how it works
Data is stored on tracks and section of the track are called sectors
(magnetic)
Operating system uses FAT(file allocation table) to find where it is located and its order
Adv hard disk drive
store large amounts
can access data randomly ( direct access)
low cost
dis hard disk drive
physical knocks can corrupt data
slower to read/write than solid state
noisy
2 types of hard disk drive
fixed ( in computer)
portable ( have own case)
adv/dis of portable drive
portable
can share files easily
quick archiving of data
scheduled back ups
can get damaged
insecure ( get stolen)
Magnetic tape
stored on a long line instead of around a disk
Must move through everything to get to end (serial storage)
used for stuff that is barely acessed
sequential storage meaning
storing data in a order eg alphabetical
Magnetic tape drive adv
cheaper than hard disk
huge data capacity
fast data transfer
magnetic tape drive dis
long time to access data (need to go through everything)
when updating another tape is needed
affected by magnetic field
which storage is faster
solid state>magnetic>optical
which has more storage
Magnetic 1-2tb >solid state1tb > Optical
cd=700mb
DVD= 4.7 gb
Blu ray = 128gb
durability
Solid state (portable) > Optical more portable than magnetic but large > Magnetic not portable because physical can damage disk
reliability
Solid state(unaffected by magnetic field) >
Optical (reliable if not scratched) >
Reliable but affected by magnetic fields
cost
optical low but lower
magnetic low (tape is cheapest)
Solid state ( more expensive but becoming cheaper)
how does optical storage work
A laser is used to read and write data
The disk has one long track on it which has pits which reflect or disperse the light which it detected as 0s and 1s
CD ROM/DVD ROM adv/dis
(read only memory)
can only be read from good for movie etc
portable ( risk of scratch thou)
less expensive than hard disk
less storage than hard disk or memory stick
slow data transer and access compared to hard disk
Read only so can’t add data
CD R/ DVD R adv/dis how it works
(recordable)
Dye which can be burned to create unreflective spots
Cheaper than RW
Once burned behaves like ROM
can only be recorded once ( if error need to throw)
Not all CD/DVD player can read it
CD RW/DVD RW adv/dis how it works
(rewrite)
has metal aloy that can be reflective or non reflective
data can be changed
less wasteful than R
possible to accidentally overwrite data
more expensive than other optical
Bluray adv/dis
Uses blue/purple laser instead (more storage cause smaller wave lengths)
has encryption
larger storage than cd/dvd
faster transfer speed and access than cd/dvd
expensive compared to other optical
Optical storage adv/dis
cheap
portable (just dont scratch)
less storage than hard disk
slow access speed
data degrades over time
solid state drive (ssd)
how does it work
Uses flash memory
non volatile memory chips contain floating gate transistors which keep their charge after being turned off
when save operation begins changes to 0
solid state drive adv
more reliable because no moving parts
small light and easily portable
quiet
faster access than disk
solid state dis
more expensive than hard disk
storage is less than hard disk
limited read write cycles ( cant be used indefinitely)
Flash memory card adv
small and durable ( no moving parts)
need little power
many sizes
can be used in camera computer phone
flash memory dis
expensive compared to HDD
lower storage than hard disk
limited read write cycles
likely to lose/stolen
