important questions Flashcards
describe how resistive touch screen tech operates
-screen made up of two layers
-user pushes top layer into bottom
-layers create a corcuit
-causes flow of electtricity
-allowing coordinates/location of user touch to be calculated
benefits of resistive touch screen
works with gloves on
isnt damaged by water
supports multitouch
cheap to manufacture
disadvantages of resistive touch screen
-lower resolution
-not very senesitive to touch
prone to scratches
-poor visibility of screen on sunlight
describe the stored concept program
data and instructons are sotred in same memory
can only be fethced one at a time
explain methods to be used to avoid accendantly losing/deleting a file
- backup file- data can be recovered
-double verification- computers sends verification to confirm user wants to delete file
what are two ways that a user coul check website uses ssl protocal
closed padlock on browser
uses https protocal
state name of updated ssl protocal
tls
explain why proxy server is used and how
-acts as an intermediary between web browser and server
-examines traffic to web server
-stops malicous traffic
-cache frequently viewed web pages
-prevents dos attacks
-stops overload of requests to web server
explain some methods to avoid spyware
using virtual keyboard or biometrics- both means keypresses cant be recorded
use antispyware-actively scans comp for any malicous malware
how does ssl work
ssl is a security protocal, provides secure. communication over the internet
uses cmvination of symmetric and aysemmetric encryption to secure data
ssl operates at transport layer, ensure data is encrypted before sent over network
explain how file is transmitted using packet switching
piece of data is split into packets
packets include-header payload and trailer
packets transmitted from sender to receiver, through multiple wires
packets may arrive out of order
router controls route- shortest most efficient rout for packet
if packet isnt received another request is sent
describe tls
also uses combination of symmetric and aysemmetric encryption to secure data, it is a newer version of ssl, provides secure comunication over internet
made up of 2 layers
-handshake layer- establishes a secure connection between two endpoints
record layer- responsible for transmitting data securely between the client and the server
explain steps in tls
uses handshake layer and record layer
-client/browser requests secure connection to server
-client/ browser requests server to identify itsled
-server provides a digital certificate
-client/ browser validates certificate
-client/ browser sends a signal back to server to begin data transmission
-encryption method will agree and session key is generated
what component in the computer is needed to access a network
nic
what type of address is allocated to component by manufacturer, used to uniquely identify device
mac address
what device on network can connect multiple device and automatically assignt them an ip addresss
router
describe what is meant by a dnamic ip address
changes everytime user logs out of page or computer turned on again, can uniquely identify device
describe infrared touch screen
leds shine infrared light accross a screen forming a matrix, when screen is thouched beams are interrupted
advantages and disadvantages of infrared touch screen
excellent resolution, high precision, durable, allows multitouch
cant work with gloves on, expensive, heat senstive
describe capactive touch screen
made up of a protective layer, a transparent conductive layer and a glass substrate, touching screen changes electrctrostatic field of conductive layer, coordinates/location of finger can be calculated
advantages / disadvantages of capactivetouch screen
excellent quality, unlimited touch life, scale well
sensitive to interfernece to light, not waterproof, not gloves
describe inkjet printers, + advantages and disadvantages
cheap, high quality image, good colour blending
slow printing
uses ink cartilidges which spray tiny bubbles of ink, with moving head, piezoelectric electricity, thermal bubble
describe laser printers, + advantages and disadvantages
higher quality text, fast printing
expensive
laser applies static charge to paper
toner- powdered ink attracted to static charge, sticks and melts producing image
uses drum
what are the two different forms of projectors
LCD and DLP
describe LCD projectors
use light of 3 colours, red, green and blue, colours are combined to form final image, high quality images
describe DLP projectors
thousands of tiny mirrors used reflect digital image from computer to screen
smaller more portable, worst quality
what are the type of screens/ monitors
LCD and LED
describe LCD screens
sandwich crystals between s sheets of glass
white back light iluminate screen from behind
crystals solid, light cant pass
electrical current applied to crystals to individual pixels, light can then pass, forming an image
cheaper, worst image quality
describe LED screens
back light used is display of LED
display made of pixels arranged in a matrix
light shone at pixels
bette quality image, better contrast and colour production, less electricity used, cost efficient, expensive at first
how does magnetic storage work
disk called platters spin constantly when comp on
read write arm moves in and out across disk surface and electromagnet is on it which is used to read or write data
give an example and properties of magnetic storage
hdd, cheap, fast, large storage
example and properties of optical storage
cd, dvd, blu-ray, low storage, slow access, portable
examples of solid state, properties
ssd, memory cards, usb- flash drive
no moving parts, compact, portable, large storage, produce less heat and power
nic
hardware device needed to connect computer to network
mac address
nic have unique address assigned to them which is the mac, assigned by manufacturer
unique address
cant be altered
48 bit long
written in hexa
24 first bits are address of manufacturer
other 24 automatically generated serial number
ip address
assigned by the isp
static and dynamic ip
ipv4 and ipv6
static ip
same address every time joins network
dynamic ip
assigned any available address when joins network, changes address
ipv4
32 bit long, denary
ipv6
128 bit long, 32 hexa characters, groups of 4 seperated by a dot
what is function of router
hardware device used to connect devices together to form a LAN
or connect LANS to form a WAN
allows devices to connect to LAN
assign IP address to devices joining a LAN
connect a LAN to internet
sends to data to correct destination on a netwrok
sends data packets to efficient route
whats a lan
computer network within single location, eg school
whats a wan
multiple lans joined together
how is laser used to store and read data from disk
laser is shined into disk, laser light reflects back and is captured by sensors
lasers burns pits onto surface of disk
uses pits and lands, 1 and 0 or on and off
what are two examples of software stored on the ssd
utility software, os or application software
state what is meant by biometric password
uses biological data
explain how firewall makes mobile device more secure
firewall gathers traffic coming and going out of server, traffic is compared to set critera, if traffic doesnt meet criteria, alert sent to warn adele, prevent hackers, and malicous attacks
what are ethical issues that could be a concern when using internet
pharming, spyware, malware, hacking, phishing, plagiarism, fake news, addiction, environmental effects, cyber bullying
why does an overflow occur
more bits that availble in register, number of bits is too big/ bigger than number of bits in register, result is bigger than 255, requires more than 8 bits to represent
describe brute force attacks
-user guesses a password
-combinations are repeatedly entered
-can be manually or automatically using a software
-password guessed until access is given
what are some aims of brute force attacks
gain personal info, delete data, change data
where is session cookies and persistent cookies stored
session- ram
persistent- hard drive
explain https
It is a secure protocol // hypertext transfer protocol secure
It is a set of rules for data transmission
It combines HTTP and SSL/TLS to transmit data
It encrypts data for transmission
State three ways that stored data can be maliciously damaged
virus
hacking
malware
purposes of os
perform basic functions of computer
manages hardware
provides an itnerface
handles interrupts
name of component in cpu that regulates number of fetch decode execute cycles cpu can perform in a second
clock
why may an error occur when data is transmitted
interferance
two advantages of owners of company sotring data in cloud storage
data can be accessed from anywhere, employees can thus work from anywhere
cloud system will back up data, meaning company doesnt need to do this
increase storage needed easily without needing to buy new hardware
one disadvantage to employees in copany of storing data incloud
needs internet to access, or else data cant be accessed
image resolution
number of pixels wife by number of pixels high
image colour depth
number of bits used to represent each colour
one benefit of increasing colour depth
greater range of colours can be used
role of router in annotated diagram
router examines packet looks for packet header, looks for ip address of destination
packet sent towards its correct destination by fastest route
router is shown connecting devices router is shown assigning an ip address to device
differences between primary and secondary storage
primary- directly accessed by cpu, secondary not
primary can be both non volatile and volatile, secondary only non volatile
primary storage faster access, secondary slower access speed of data
describe an expert system
has a rule base that contains a list of facts, the itnerference engine appies knowledge bse to the rule base to reach a diagnosis for repair of cr. the user provides data to system using an interface
describe what is meant by machine learning capabilities
trained, form of ai
analyses patterns stored succesfully or not results
adapts and reflects
can improve or adapt without human influence/ input
how is hexadecimal used in website development
html colour codes
how does lossy compression reduce file size of videos
A compression algorithm is used
The resolution could be reduced
Colour depth could be reduced // bits per pixel reduced
Sounds not heard by human ear could be removed
Repeating frames could be removed
what uses position and alignment marks for orientation
QR CODE
explain how ssl protocal secures the data for transmission (2)
encrypts data
based on authentication of an ssl certificate
describe operation of an HDD and how it stores data
has platters
platters diveded into tracks
platter spins
magnetic field determines binary value
read/ write arm moves in and out of platter
arm has electromagnetic properties
describes how lossy compression functions
compression algorithm used
permenantly removes data
sample resolution reduced
reduced frame rate
reduced colour depth
explain how phishing obtains personal data
fake email sent to user
contains link to false website
user clicks link and enters personal details
what type of language can be used to directly manipulate hardware in the comp
assembly lang and machine code
what type of lang is portable
high level language
identify ways in which data can be accidentally damage
hardware or software failure
fire
flood
what type of sensor can check if vehicle too high
light
what type of sensor can count the vehicles enetering car park
pressure
is the ram contained in the cpu
no
what error check checks for errors in data entry
check digit
what error check checks for errors in data after transmission
checksum
describe process of interrupt
interrupt generated
given rpiority
interrput queued
Interrupt stops CPU from processing current task
CPU will service interrupt // Interrupt handler services interrupt …
MAR
register that holds address of data needs to be fetched
PC
next instruciton to be fetched
what are multimedia format that stores video and audio
MP4
what file stores sound
MP3
what files contain instructions on how to create the sound
MIDI
explain why user uses a compiler rather than interpreter
produces exectuable file
would not realease source code
source code cant be edited
no need to be translated everytime
mdr
stores data that has been fethed
firmware
type of software stored in rom, incldues basic input output system bios, and bootlander
ascii vs unicode
ascii uses 7/8 bit per charcter
unicode uses 16/32 bits per character
ascii limited languages that cna represent
unicode many languages including emojis
ascii represent less characters than unicode
features of solid state storage
volatile or not
uses flow gates
uses control gates
transistors
uses nand or nor tech
examples of software interrupts
division by zero
null value
two processes trying to access same memory
