Bad Flashcards
Moisture sensor description
measures water levels
How does an SSD store data (6)
uses NAND/NOR technology/flip-flops
stores data by flashing it onto chips
transistors controls flow of electrons
electric current reaches control gate
current flows through to floating gate to be stored
when data is stored transistor is converted from 1 to 0
Advantages of resistive (2)
cheap technology
can use gloved fingers to input
Disadvantages of resistive (3)
does not allow multi-touch
poor visibility in sunlight
vulnerable to scratches
Features of freeware (3)
user cannot access source code - cannot fix bugs
software covered by copyright
user needs owner’s permission to do anything
Define a core
made up of ALU, control unit, registers
Define hacking
gaining illegal access to computer system without user permission
Features of operating system (4)
allow user to communicate with computer
stored on HDD/SSD + RAM
enables computer system to function correctly
provides environment where applications can be run
How does cloud storage work (3)
data stored on remote servers
same data stored on more than one server - clients can access data at any time
owned and managed by company
When does an interrupt occur when printing (3)
paper jam
out of ink
out of paper
Function of an NIC
allow device to connect to network
Disadvantages of low-level language (2)
longer to write programs
programs more difficult to understand
Define an automated system (2)
combination of software and hardware
programmed to work automatically
Define the world wide web (2)
collection of websites/webpages
uses internet to get info from web servers
How might parity checks not detect an error
if there is an even number of bits changed
How optical mouse works (5)
shines LED under mouse
light reflects back through lens
converted to value
value transmitted to computer
computer determines direction and speed of movement
What is used to read and write data on CDs/DVDs
a red laser
Description of level sensor
detects liquid levels
When are inkjet printers used? (3)
high quality images
photographs
low volume printing
Define robotics (2)
branch of computer science
incorporates operation of robots
Define a control bus (3)
Carries signals to other components of CPU
directs CPU
unidirectional or bidirectional
Define blockchain (2)
decentralised database
time-stamped ledger of permanent records
Disadvantages of an automated system in industry (4)
expensive to set up
events can occur which system not programmed to respond to
subject to cyber attacks
need enhanced maintenance which can be expensive
Define mp3
lossy for audio files
Solutions to hardware failure
maintain hardware
What is an HTML’s presentation (2)
style of document
format of webpage
When is ROM used
BIOS (basic input and output system)
Description of gas sensors
detect gas being monitored + produce outputs
Benefits of laser printer (3)
can print duplex (on both sides of paper)
Faster printing
Cheaper long term (does not have to purchase ink cartridges)
Description of NOR gate
arrowhead with circle in front
Advantage of infrared touchscreens (3)
allow multi-touch
allows gloved fingers to be used
durable
Examples of SSD (2)
memory cards
USB flash memory drive
Disadvantages of HDD (2)
hard disk can have slow data access when compared to RAM
can have latency - time delay
Describe the fetch decode execute cycle (7)
PC has address of next instruction to fetch
address in PC copied to MAR via address bus
instruction copied from MAR to MDR
instruction copied from MDR to CIR
CPU decodes instruction in CIR to determine what operation needs to be performed
executed by sending signals via control bus to computer components
value in PC incremented by 1 to point at next instruction to fetch
How does virtual memory work
moves oldest data out of RAM into HDD when RAM is full
Router (2)
network component
uses IP address to send data to correct destination
How does ARQ work (4)
uses positive/negative acknowledgements
send acknowledgement that data received
if acknowledgement not received = data resent in timeout until positive acknowledgment received or set number of retransmissions reached
error detected = request to resend data
Disadvantages of USB (3)
cable length only 5 m
data transfer rate slow compared to others
early USB models may not be supported by modern computers
Drawbacks of virtual memory (2)
disk thrashing - system too busy moving data in out of memory to do anything
slower as it is using data from secondary storage
Solutions to software failure
make sure software is up to date
Description of infrared passive sensors
measure heat radiation given by object
Define source code
original program
QR code benefits (3)
hold more data
easier to read - can be read just using cameras
easier to transmit QR codes
Disadvantages of echo checks
not known whether error occurred when first sending data or when sending data back
Characteristics of expert systems (4)
have knowledge base
have rule base
have inference engine
have interface
Blu-ray applications (3)
record high definition tv programs
skip quickly to any part of disk
edit programmes on disk
Disadvantages of GUI (3)
uses more memory than CLI
user limited to icons provided on screen
needs operating system to operate
Purpose of DDoS attack (2)
deny people access to a website
floods network with useless spam traffic
Function of CIR
stores current instruction being decoded/executed
Solutions to water destroying data (2)
no water near device
keep device in waterproof box when not used
Define lossless file compression
data from original file reconstructed
Features of application software (2)
provides services user requires
allows user to execute software when required
Define an address bus (2)
carries address locations of next item to be fetched
data travels one way ( unidirectional)
Example of domain type (2)
.com
.net
Features of assemblers (5)
program
translates assembly language/low-level language to machine code
1 LLL statement translates = 1 machine code instruction
usually distributed for general use
translated programs able to run without assembler
How keyboard works (4)
key pushes switch on circuit board
completes circuit
location of press calculated
location corresponds to ASCII value
How echo checks work (3)
copy of data sent to sender by receiver
copy compared with original
no difference = no error
Solutions to data being damaged from power surge (2)
use UPS
provides back up power once original power source fails
Features of SSL (3)
type of protocol
transmits data securely
computer rules to communicate across network
OR gate rule
output = 1 if either input = 1
How can a mobile phone be used without removing gloves
use capacitive gloves - allows charge to be disturbed
Define HTTP(s) (2)
protocol used when transferring files across internet
uses encryption
NOR gate rule
output = 1 if neither inputA OR B = 1
How parity checks work (3)
parity is EVEN or ODD (number of 1 bits)
left most bit is parity bit
change = change in even or odd bits = error
How microphone works (3)
diaphragm vibrates producing electric signal
signal goes to sound card
converted into digital values
Define a cookie (2)
small files on user computer
contains data about user history/preference
Define object code
code after compilation
How LCD works (5)
light generated by a bulb
light sent to group of chromatic-coated mirrors
mirrors reflect light back at different wavelengths
images combined using prism to create full colour image
image passed through projector lens onto a screen
Description of accelerometer sensor
measure motion of object
Benefits of virtual memory (2)
programs larger than RAM can still be executed
reduces need to buy more RAM
Disadvantages of capacitive touchscreen (2)
cannot use when wearing gloves
screen will shatter on impact
Advantages of capacitive touchscreen (3)
allows multi-touch
durable surface
good visibility in sunlight
What does SSL stand for
secure socket layer
How is a webpage received (5)
Disadvantage of packet switching (2)
packets can be lost
delay at destination where packets are re-ordered
Solutions to fire destroying data (2)
keep device in fireproof box when not used
use electrics safety
Define a CPU (3)
is microprocessor/processor
executes all instructions in computer application
carries out calculations
Define brute force attacks
trying different combinations of letters/numbers/symbols until password found
Function of ACC (2)
carries ALU calculations
stores data temporarily during those calculation
Define firmware
program that provides low level control for devices
Data in packet header (4)
IP address of sender
IP address of receiver
Sequence number of packet (to reaarange in order)
Size of packet in bytes
How encryption works (3)
plain text encrypted using algorithm/key
key transmitted separately from text
key used to decrypt the cypher text
Features of viruses (3)
program that replicates
corrupt files + cause computer to malfunction
need active host program/infected OS to work
Advantages of interpreters (2)
quicker to debug - stop translation once error detected
portable - can run on any platform as source code included in translation
Description of flow sensor
measure flow rate of liquid/gas and produce output
How DLP screen works (5)
uses tiny mirrors
mirrors laid out in grid
mirrors tilt towards/away from light source
mirrors reflect light towards lens
colour produced using colour wheel
Define AI (2)
branch of computer science
simulation of intelligent computer behaviour
Define social engineering (2)
manipulating people into giving personal data
e.g Phishing + Malware
How SSL works (5)
browser sends message to connect with website
browser requests web server to identify itself
web server sends SSL certificate copy to browser
web browser authenticates certificate
sends message to server to allow communication
Description of humidity sensor
measures amount of water vapour in air sample
Examples of system software (3)
compiler
device driver
operating system
Functions of operating systems (6)
handles interrupts
manages memory/files
allows multitasking
manages peripherals
platform for running application software
provide interface
Differences between IPv6 + IPv4 (3)
IPv4 written in denary, IPv6 written in hexadecimal
IPv4 is 32 bit, IPv6 is 128 bit
IPv4 separated with dots, IPv6 separated with colons
ROM features (3)
non-volatile - data not lost once computer powered off
ROM is permanent - cannot be changed, contents can only be read
often stores instructions a computer needs to access when powering up
Temperature sensor description
measures temperature of surroundings
Function of RAM (4)
store data currently in use
store files currently in use
store part of application currently in use
store part of operating system currently in use
Software stored on SSDs (3)
operating system
application software
utility software
Benefits of packet switching (2)
no need to tie up single communication line
high transmission rate possible
How CDs/DVDs work (5)
laser shone at disk
arm moves laser across disk surface
laser burns pits onto disk surface
laser reads the pits and lands on disk surface
reflected light from laser shining on disk is captured by sensor
Disadvantages of Expert Systems (3)
high costs
requires lots of training
only have facts entered into system
Benefits of compilers (4)
compiled program can be stored for use
compiled program can be executed without compiler
compiled program takes up less memory when executed
compiled program executed in shorter time
Disadvantages of robots (4)
lead to unemployment
expensive
risk of deskilling
difficult to do non-standard tasks
Benefits of persistent (permanent) cookies
no need to type login details when visiting website
How digital cameras work (5)
images converted from analogue to digital using ADC
image turned to pixels
each pixel given value/colour
pixels form grid
pixels stored in sequence
