theory dont know Flashcards
magnetic
- has platters
- that spin
- has read / write arm
- magnetic field determines binary value
magnetic +/-
+ large storage
+ cheap
+ fast read / write
- not durable (lots of parts)
- sealed unit (hard to fix)
- not portable
optical
- disk with a spiral
- binary represented by pits and lands
- laser shines on disk and light is reflected differently to determine binary value (read)
- laser indents disk (write)
optical +/-
+ cheapest
+ portable
+ small
- less storage
- easily scratched / damaged
solid state
- sends current which forces electrons through barrier
- traps them in floating gates
- binary data stored by held electrons
(flash memory)
solid state +/-
+ no moving parts (durable)
+ faster read / write
+ faster start up
+ quiet
+ don’t need defrag
- expensive
why cloud storage grown
- bandwidth increased - fast internet available
- cheaper
- more choice of company
- more small portable mobil devices
hdd can ssd
hdd
- longer read / write
- cheaper for more data stored
ssd
- no moving parts (durable)
- faster read / write
cloud + / -
+ access anywhere
+ central back up
+ managed by 3rd party
+ cheaper comp
+ easy to share
- if no internet no access
- privacy of 3rd party staff
- malware /hackers
- rely on 3rd party security
- long subscription (expensive)
protocol layers
application
transport
internet
link
application layer
data encoded
HTTP
FTP
IMAP
SMTP
transport layer
connection between devices
establishes language and packet size
splits data into packets
TCP
UDP
internet layer
addresses and packets data
IP
link layer
contains network hardware
attaches MAC address
NIC
OS drivers
MAC address
- every networked device has one
- assigned by manufacturer
- identifies the device (hardware)
- never changes