Component 1 Flashcards
Why is secondary storage needed?
Rom is read only and Ram is volatile
What is the benefit of optical media?
Thin, lightweight and portable
What are the downsides of optical media?
Low capacity, slow access times, dust/scratches can damage
What are the benefits of magnetic storage?
High capacity and access speeds
What are the downsides of magnetic storage devices
Has moving parts which will eventually fail
Performs better if defragmented
What are the benefits of SSDs
Very quick to access
very reliable
no noise
low power consumption
no need to defragment
what are the downsides of SSDs
Expensive
limited number of read-write cycles
What are the benefits of using binary?
easier to manufacture - cheaper
more reliable
How are text file sizes calculated?
bits per character X number of characters (including spaces)
How are image file sizes calculated?
colour depth X image height (px) X image width (px)
How are sound file sizes calculated
sample rate X duration (s) x bit depth
What is 0 + 0 in binary addition?
0
What is 0 + 1 in binary addition?
1
What is 1 + 1 in binary addition?
0 carry 1
What is 1 + 1 + 1 in binary addition?
1 carry 1
What is the effect of a binary shift left?
X 2 per bit
What is the effect of a binary shift right?
/ 2 per bit
What is a character set?
A defined list of characters recognised by a computer
Each character is represented by a __________________
unique binary number
How are bitmap images stored?
constructed from pixels
How are vector images stored?
mathematics to draw coloured shapes stored
Each pixel of a bitmap is stored in ___________
Binary
How do you calculate the number of colours available in a image?
2^n where n = number is bits per pixel
What is the number of bits per pixel known as?
colour depth
What is metadata
data stored within the image to define the width, height, colour depth and colour palette
What is bit depth?
number of bits stored per sample
What is sample rate?
number of samples stored per second
What does compression do?
Reduce number of bits in a file
What are the effects of lossy compression
Some data is lost
Greatly reduces file size
Reduces quality of image/sound
Cannot be used on text or executable files
What are the effects of lossless compression?
No data is lost, it is encoded differently
Can be revered to original format
can be used on all types of data
usually less effective than lossy
most suitable for documents and executable files
What are the advantages of networking?
Users can share files and peripherals
Users can access files from any computer on the network
Servers can control security, software updates and the backing up of data
communication with other people
give facts about LANs
local area network
network over a small geographical area
all hardware owned by organisation
wired using UTP or fibre optic OR wireless
Give facts about WANs
wide area network
covers wide geographical area, connecting LANs
Infrastructure is leased from telecommunications companies who own and manage it
connected with telephone lines, fibre optic cables or satellite links
give facts about bandwidth
how much data can be sent on the transmission media
measured in bits per second
higher bandwidth = better performance
How does the number of users affect network performance?
Too many users can slow down the network if there is insufficient bandwidth
How does transmission media affect network performance?
Wired connections have higher bandwidth than wireless
fibre optic has higher bandwidth than copper cables
Give facts about latency and its affect on the performance on a network
caused by bottlenecks
higher latency means lower performance
explain the client-server model
Server manages internet access
Server manages printing jobs
server provides email services
server runs data backup
clients make requests for data and connections
what are the advantages of the client-server model?
easier to manage security files
easier to make backups of all shared data
easier to install software updates on all computers
what are the disadvantages of the client - server model?
can be expensive
requires IT specialists to maintain
server is a single point of failure
users will loose access if the server fails
Explain the peer to peer model
A peer is a computer on the network and it is equal to all other peers
peers serve their own files to each other
each peer is responsible for it’s own security
each peer is responsible for it’s own backup
peers usually have their own printers
What are the advantages of the peer to peer network?
very easy to maintain
no specialist staff required
no dependency on a single computer
cheaper to set up - no expensive hardware required
what are the disadvantages of a peer to peer network
generally less secure
users will need to manage their own backups
can be difficult to maintain a well ordered file store
List the hardware necessary for a LAN
network interface controller
switch
router
What is the internet?
A global collection of connected networks
Where are web addresses converted to IP addresses?
domain Name service resolver server
clients ________/________ resources from a server
request/use
Give facts about a star network
most popular wired type
central switch
all devices connected to central switch
switch is intelligent and ensures traffic only goes where wanted
What are the advantages and disadvantages of a star topology?
Advantages
If a single cable breaks, only that computer is effected
Disadvantages
switch is a serious point of failure
What is a full mesh topology
Every device connected to every other
What are the advantages / disadvantages of a full mesh topology?
Advantage: if any connection breaks, there is a alternative route
disadvantage : very expensive and impractical for large networks
What is a partial mesh topology?
Multiple routes
however not every device is connected to every other device
compromise solution which reduces hardware needed compared to full mesh
What is ethernet?
a standard for networking technologies
used for communicating on a WAN
includes a number of associated protocols
Explain how encryption works
1) data is scrambled into ciphertext using a master key created from the SSID other network and the password
2) Data is decrypted using the same master key, so important it is not transmitted
A handshake protocol is used to ensure that the receiver has a valid master key before transmission to the device begins.
