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
IP address
- every networked device has one
- assigned by network
- identifies device on a network (software)
- can change depending on location and network
EAN vs LAN
- many location vs one
- heavy traffic vs faster transmission
- shared ownership vs single ownership
- public vs private
system vs application software
system
- platform for other softwares to run
- manages operation on a comp
application
- installed by user to allow them to perform tasks
OS
application management
security management
storage management
input / output device management
application management
- allows download of authorised programs
- can prevent certain apps
- controls updates
security management
- authentication
- blocks certain software
- protects against malware
storage management
- manages devices
- loads data to memory
- manages space - over writing prevented
input / output device management
- manages devices and drives
- handles interrupts
- controls communication - allows sending / receiving
data compression
- smaller files - fewer packets so faster transmission and reduced traffic
- reduced download times (streaming)
- images on web pages download faster
- more space on disks or servers
- less storage is cheaper
