wrong questions Flashcards
(31 cards)
data privacy concerns an orgranisation needs to consider when setting up a wireless network
- eavesdropping; all network data is broadcast and can be intercepted by third party;
• encrypting data; making sure that data is not transmitted in plain text; by ensuring that routers have encryption turned on;
• malware infiltration; a Wi-Fi network is more exposed to attack because it’s visible; - malicious hotspots; unofficial access points that look like they are part of the network
examples to use a captcha system
account registration
account access
online voting systems
ticket purchasing/transaction completion
http and https
Provides a way for users to interact with web resources.
Transmits messages between client and server using hypertext.
https
As HTTP but in addition uses an encryption protocol to ensure communications are secure.
smtp
enables users to send and recieve email messages
Initiates sessions between user and mail server. server then forwards messages.
Uses a process called ‘store and forward’
to store messages and forward as necessary. The server decides which server to send the message to and the inbox provider then downloads the message and places it in the recipient’s inbox.
ip
Relays data across network boundaries. It defines how to address and route each packet to make sure it reaches the destination
lossy vs lossless
when decompressed, some data and detail is permanently lost
when decompressed the original file is restored with no loss of data
RAM vs ROM
volatile, non volatile,
contains programs data and files in use; contains bootstrap
temporary; permanent
larger capacity than ROM
can be edited, cannot be edited
why only binary computers
computers are made of switches
which can only be two states: on and off
why must sound be converted to digital
computer systems use binary
sound is analogue—continuous
why high level is better
have built in functions
built in libraries
have structures, e.g. selection and iteration
fewer lines of code are written
quicker to develop code
easier to find mistakes
code is easier to maintain/understand
protocol
a set of rules
that allows two devices to communicate
why computer networks better
Share hardware; A. by example
Share data/files;
Easier to work collaboratively;
Use of communication tools
Central management for machines A. by example: centralised software deployment, centralised back-ups;
Files not stored on local machine so can be accessed from multiple machines;
Can monitor computer users;
Increase available storage;
how do magnetic disks work
on a hard disk binary data is represented by tiny magnetised regions
where the magnetic orientation in one direction represents 0, and other direction represents 1
when reading data the read/write head is moved onto the correct track and the disk spins round
a whole sector is read in one go
unicode better than ascii
can represent a wider range of characters
can represent characters from wider range of languages
can represent characters used in scientific/mathematical/specialist documents
hex and binary space
number is still represented using binary in computer memory
so it will take up the same space
interpreters
do not produce any machine code so the program needs to be translated each time it is executed
they call machine code subroutines within their own code to carry out commands/ directly execute the instruction
translating a line at a time which it then executes immediately
if a runtime error is found the interpreter stops
compilers
translates the whole program
standalone program doesn’t require the compiler/source code on computer to run
produces a list of syntax errors after translation
doesn’t execute the programming code
why do computers have more RAM than chache
RAM is cheaper
typically the capacity of cache memory is not enough to store both data and programs
why is cloud storage better than local storage
- enables user to access their data from more places/devices;
• enables user to more easily share data with others (can make parts of their cloud storage publicly available) // To allow sharing of files;
• increases the amount of potential storage available;
• reduced cost of computing devices for users as no need for as much built-in secondary storage // Can potentially purchase a cheaper (lower spec)
• to allow concurrent access/collaboration;
• cloud storage is automatically backed up by the host;
sample resolution definition
the number of bits per sample
differences between lans and wans
LANs cover relatively small geographical areas // WANs usually cover a wide geographic area;
• LANs often owned and controlled/managed by a single person/organisation // WANs often under collective/distributed ownership;
• WANs are (usually) several LANs connected together;
• WANs (usually) have a much larger number of devices/users than LANs;
• LAN has a lower latency // WAN has higher latency;
• WANs are (usually) slower than LANs;
• the cost-per-byte for transmission is much higher on a WAN;
• LANs and WANs use different protocols;
hertz
how many samples per second
1hz = 1 sample per second
sampling rate
the number of samples taken per second
advantages of using wireless
flexibility to expand network/add users/add own devices to the network;
• there is no need to drill holes/install cabling;
• mobility of user/devices;
• modern devices are more likely to (be designed to) connect wirelessly;
• guest access;
• no trip hazards;
