Bad Flashcards
(260 cards)
1
Q
Moisture sensor description
A
measures water levels
2
Q
How does an SSD store data (6)
A
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
3
Q
Advantages of resistive (2)
A
cheap technology
can use gloved fingers to input
4
Q
Disadvantages of resistive (3)
A
does not allow multi-touch
poor visibility in sunlight
vulnerable to scratches
5
Q
Features of freeware (3)
A
user cannot access source code - cannot fix bugs
software covered by copyright
user needs owner’s permission to do anything
6
Q
Define a core
A
made up of ALU, control unit, registers
7
Q
Define hacking
A
gaining illegal access to computer system without user permission
8
Q
Features of operating system (4)
A
allow user to communicate with computer
stored on HDD/SSD + RAM
enables computer system to function correctly
provides environment where applications can be run
9
Q
How does cloud storage work (3)
A
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
10
Q
When does an interrupt occur when printing (3)
A
paper jam
out of ink
out of paper
11
Q
Function of an NIC
A
allow device to connect to network
12
Q
Disadvantages of low-level language (2)
A
longer to write programs
programs more difficult to understand
13
Q
Define an automated system (2)
A
combination of software and hardware
programmed to work automatically
14
Q
Define the world wide web (2)
A
collection of websites/webpages
uses internet to get info from web servers
15
Q
How might parity checks not detect an error
A
if there is an even number of bits changed
16
Q
How optical mouse works (5)
A
shines LED under mouse
light reflects back through lens
converted to value
value transmitted to computer
computer determines direction and speed of movement
17
Q
What is used to read and write data on CDs/DVDs
A
a red laser
18
Q
Description of level sensor
A
detects liquid levels
19
Q
When are inkjet printers used? (3)
A
high quality images
photographs
low volume printing
20
Q
Define robotics (2)
A
branch of computer science
incorporates operation of robots
21
Q
Define a control bus (3)
A
Carries signals to other components of CPU
directs CPU
unidirectional or bidirectional
22
Q
Define blockchain (2)
A
decentralised database
time-stamped ledger of permanent records
23
Q
Disadvantages of an automated system in industry (4)
A
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
24
Q
Define mp3
A
lossy for audio files
25
Solutions to hardware failure
maintain hardware
26
What is an HTML's presentation (2)
style of document
format of webpage
27
When is ROM used
BIOS (basic input and output system)
28
Description of gas sensors
detect gas being monitored + produce outputs
29
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)
30
Description of NOR gate
arrowhead with circle in front
31
Advantage of infrared touchscreens (3)
allow multi-touch
allows gloved fingers to be used
durable
32
Examples of SSD (2)
memory cards
USB flash memory drive
33
Disadvantages of HDD (2)
hard disk can have slow data access when compared to RAM
can have latency - time delay
34
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
35
How does virtual memory work
moves oldest data out of RAM into HDD when RAM is full
36
Router (2)
network component
uses IP address to send data to correct destination
37
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
38
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
39
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
40
Solutions to software failure
make sure software is up to date
41
Description of infrared passive sensors
measure heat radiation given by object
42
Define source code
original program
43
QR code benefits (3)
hold more data
easier to read - can be read just using cameras
easier to transmit QR codes
44
Disadvantages of echo checks
not known whether error occurred when first sending data or when sending data back
45
Characteristics of expert systems (4)
have knowledge base
have rule base
have inference engine
have interface
46
Blu-ray applications (3)
record high definition tv programs
skip quickly to any part of disk
edit programmes on disk
47
Disadvantages of GUI (3)
uses more memory than CLI
user limited to icons provided on screen
needs operating system to operate
48
Purpose of DDoS attack (2)
deny people access to a website
floods network with useless spam traffic
49
Function of CIR
stores current instruction being decoded/executed
50
Solutions to water destroying data (2)
no water near device
keep device in waterproof box when not used
51
Define lossless file compression
data from original file reconstructed
52
Features of application software (2)
provides services user requires
allows user to execute software when required
53
Define an address bus (2)
carries address locations of next item to be fetched
data travels one way ( unidirectional)
54
Example of domain type (2)
.com
.net
55
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
56
How keyboard works (4)
key pushes switch on circuit board
completes circuit
location of press calculated
location corresponds to ASCII value
57
How echo checks work (3)
copy of data sent to sender by receiver
copy compared with original
no difference = no error
58
Solutions to data being damaged from power surge (2)
use UPS
provides back up power once original power source fails
59
Features of SSL (3)
type of protocol
transmits data securely
computer rules to communicate across network
60
OR gate rule
output = 1 if either input = 1
61
How can a mobile phone be used without removing gloves
use capacitive gloves - allows charge to be disturbed
62
Define HTTP(s) (2)
protocol used when transferring files across internet
uses encryption
63
NOR gate rule
output = 1 if neither inputA OR B = 1
64
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
65
How microphone works (3)
diaphragm vibrates producing electric signal
signal goes to sound card
converted into digital values
66
Define a cookie (2)
small files on user computer
contains data about user history/preference
67
Define object code
code after compilation
68
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
69
Description of accelerometer sensor
measure motion of object
70
Benefits of virtual memory (2)
programs larger than RAM can still be executed
reduces need to buy more RAM
71
Disadvantages of capacitive touchscreen (2)
cannot use when wearing gloves
screen will shatter on impact
72
Advantages of capacitive touchscreen (3)
allows multi-touch
durable surface
good visibility in sunlight
73
What does SSL stand for
secure socket layer
74
How is a webpage received (5)
75
Disadvantage of packet switching (2)
packets can be lost
delay at destination where packets are re-ordered
76
Solutions to fire destroying data (2)
keep device in fireproof box when not used
use electrics safety
77
Define a CPU (3)
is microprocessor/processor
executes all instructions in computer application
carries out calculations
78
Define brute force attacks
trying different combinations of letters/numbers/symbols until password found
79
Function of ACC (2)
carries ALU calculations
stores data temporarily during those calculation
80
Define firmware
program that provides low level control for devices
81
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
82
How encryption works (3)
plain text encrypted using algorithm/key
key transmitted separately from text
key used to decrypt the cypher text
83
Features of viruses (3)
program that replicates
corrupt files + cause computer to malfunction
need active host program/infected OS to work
84
Advantages of interpreters (2)
quicker to debug - stop translation once error detected
portable - can run on any platform as source code included in translation
85
Description of flow sensor
measure flow rate of liquid/gas and produce output
86
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
87
Define AI (2)
branch of computer science
simulation of intelligent computer behaviour
88
Define social engineering (2)
manipulating people into giving personal data
e.g Phishing + Malware
89
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
90
Description of humidity sensor
measures amount of water vapour in air sample
91
Examples of system software (3)
compiler
device driver
operating system
92
Functions of operating systems (6)
handles interrupts
manages memory/files
allows multitasking
manages peripherals
platform for running application software
provide interface
93
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
94
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
95
Temperature sensor description
measures temperature of surroundings
96
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
97
Software stored on SSDs (3)
operating system
application software
utility software
98
Benefits of packet switching (2)
no need to tie up single communication line
high transmission rate possible
99
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
100
Disadvantages of Expert Systems (3)
high costs
requires lots of training
only have facts entered into system
101
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
102
Disadvantages of robots (4)
lead to unemployment
expensive
risk of deskilling
difficult to do non-standard tasks
103
Benefits of persistent (permanent) cookies
no need to type login details when visiting website
104
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
105
How does a disk defragmenter work
rearranges blocks of data to store files in contiguous sectors
106
How USB connects to device (3)
computer automatically detects that device present
USB loads appropriate device driver for communication
new device detected = user prompted to download appropriate device driver software
107
Examples of internal secondary storage (2)
HDD (Hard Disk Drive)
SSD (Solid State Drive)
108
How does SRAM work
uses flip-flops which hold each bit of memory
109
Features of persistent (permanent) cookies (3)
remember user's log in details
stored on hard drive of user computer until expiration date/deleted
still exists even if browser closed
110
Function of core (2)
process instruction
carry out fetch-decode-execute cycle
111
How packet switching works (3)
data split into packets
each packet sent independently
packets reassembled into correct order at destination based on information in header
112
How inkjet printer works (3)
print head moves nozzles side to side across page
nozzles spray liquid ink droplets on paper
ink droplets created using piezoelectric or thermal bubble technology
113
Features of worms (3)
standalone virus - no need for host
replicates and spreads to other computers
arrive as message attachment
114
features of spyware (3)
software
gathers info based on user's actions
sent info to cybercriminal
115
Drawbacks of SSD (3)
does not last long
higher cost
sensitive to high temperatures + power loss
116
Advantages of Expert System (3)
consistent results
fast response speed
can store lots of facts
117
Similarities between IPv4 + IPv6 (3)
both unique
can be static/dynamic
assigned by router/ISP
118
Advantages of GUI (3)
user doesn't need to learn any commands
icons represent applications - more user friendly
pointing device click on icon to launch application - simpler than typing commands
119
How to prevent brute force attacks (2)
locking device once certain number of incorrect passwords guessed
strong password
120
DVD and CD differences
DVD has larger storage capacity
121
Name the 2 types of cookies
session cookie
persistent (permanent cookie)
122
How operating system manages peripherals
allows communication with input/output devices using device drive
123
Example of HTML presentation (3)
colour
font size
font style
124
How laser printer works (5)
laser removes charge in certain areas of drum - creates shape of content to be printed
toner attracted to charged areas --> stick to drum
charge applied to sheet of paper - toner attracted to paper
fusers melt toner onto paper
discharge lamp removes static charge from the drum
125
How does symmetric encryption work
uses same key to encrypt/decrypt message
126
How is a webpage sent (2)
127
Description of light sensors
produce output depending on light brightness
128
Description of infrared active sensors (2)
use invisible infrared beam
beam broken = change in amount of infrared reaching sensor
129
How QR code works (7)
scanned by camera
light reflected back
black squares reflect less than white squares
3 large squares define alignment
square's data decoded - each square has binary value
processed by app
links to website or document
130
Benefits of SSDs over HDDs (4)
no moving parts - more reliable/less damage
small
data is faster than HDD
lower power consumption
131
When are laser printers used? (2)
high speed printing
large volume printing
132
Examples of utility software (5)
virus checkers
defragmentation software
file compression
file management
back-up software
133
Advantages of high-level language (4)
quicker to write programs
easier to debug programs
independent of type of computer used
code is portable
134
Description of pressure sensors
generates different electric currents depending on pressure applied
135
Advantages of robots (4)
higher productivity
less expensive in long run (no pay)
more consistent
can work in hazardous environments
136
What is the protocol for URL (2)
http
https
137
QR code disadvantages (2)
can be used to transmit malicious codes
more than one QR format available
138
Shareware meaning (3)
trial version of software with limited features
user needs to pay fee to access full version
protected by copyright
139
Features of compilers (5)
program that translates HLL to machine code
translates whole code at same time
produces executable file of machine code
usually distributed for general use
program able to run without compiler
140
How operating system manages memory (4)
manages movement of data to and from RAM e.g movement from RAM to secondary storage
keeps track of status of memory locations
memory protection - ensures 2 applications cannot use same memory location at same time
141
Define Cache memory (4)
temporary memory using static RAM
located within CPU
stores frequently used instructions
stores data that needs to be accessed faster
142
Function of IDE (2)
software
helps writing/development of programs
143
Inkjet disadvantages (3)
ink cartridges dont last long
expensive to run
printing can smudge
144
Features of ransomware (2)
encrypt data on user computer
user pays cybercriminal to send decryption key
145
Define a data bus (2)
Carries data being processed
Data travels in both directions (bi-directional)
146
Define a buffer
memory area that stores data temporarily
147
Difference between Blu-ray and DVDs (4)
Blue ray uses blue laser - shorter wavelength
shorter wavelength allows pits and lands to be smaller - stores 5 times more data than dvd
blu ray automatically comes with encryption
blu ray data transmission is faster than dvd
148
Features of synchronous data transmission (5)
continuous stream of data
data accompanied by timing signal
synchronizes sender and receiver
receiver counts number of bits sent
reassembles into bytes
149
Define domain name
website name
150
Description of XOR gate
arrowhead with line behind
151
Laser printer disadvantages (3)
larger carbon footprint
more time to warm up
toner cartridge more expensive
152
Function of ALU
carries out arithmetic/logic operations while program being run
153
How DDoS attacks work (4)
multiple computers used as bots
lots of requests sent to a server at the same time
server cannot respond to all requests
causing server to fail
154
Factors which determine the performance of the CPU (4)
clock speed
width of address/data bus
cache
size of core
155
Features of trojan horse (3)
program disguised as genuine software
carries harm to user computer system
will give cybercriminals user personal info
156
Example of HTML structure (2)
contents in header
main contents of website
157
Advantages of synchronous data transmission
faster
158
How data can be damaged accidentally (4)
Fire + water
power surge
data accidentally deleted
hardware + software failure
159
Function of MAR
temporarily stores address of memory location of data to be accessed
160
Define inference engine (2)
gathers information from users by asking questions
examines knowledge base for data which matches queries
161
Description of OR gate
arrowhead
162
Describe how a barcode scanner works (5)
red laser shone on barcode
light reflected back (white lines reflect more light)
sensors detect light
microprocessor decodes data
bars will give different binary values
163
Difference between primary memory and secondary storage (5)
primary memory directly accessed by CPU while secondary storage not
Secondary storage is all non-volatile
secondary storage can be external or internal to computer
Primary storage faster to access than secondary storage
primary has less storage capacity
164
Function of HTML
developing web pages
165
Define digital currency (3)
form of payment
transfers money from accounts in transactions
exists in electric form only
166
Define mp4
lossy for multimedia files
167
How compilers react to error
error report produced instead of compiled program
168
Features of free software (3)
user can access source code - fix bugs
user can redistribute program
source code can be studied for educational purposes
169
Disadvantages of keyboard (3)
dirt/food can get into keys
easy to make a mistake
can be slow
170
How 2D scanner works (5)
paper placed on a glass panel
light illuminates document
scan head moves across document
lens focuses on document image
scanned image turned to electric form by CCD (charge coupled device)
171
Consequence of disk fragmentation (2)
slower data access time
HDD read-write head requires several movements to find/retrieve data
172
How operating system manages files (3)
allows user to save file
allows user to create file
allows user to delete file
173
Define dynamic IP address (2)
assigned by ISP when device logs on to internet
change
174
Description of NAND gate
curved rectangle with circle in front
175
Differences between RAM and ROM (4)
RAM is a temporary memory device while ROM is a permanent memory device
RAM is volatile while ROM is non-volatile
RAM can be edited but ROM cannot be altered
RAM used to store data currently in use while ROM stores data needed to start up
176
Cloud storage drawbacks (3)
unstable internet can cause problems accessing files
can be expensive if large storage capacity required
cloud storage can fail and lose all data
177
What does the website address contain (4)
domain host
domain name
domain type
country code
178
Purpose of the secondary storage (4)
permanently stores data
loads application software
loads operating system
allows user data to be accessed
179
Why might a capacitive touchscreen not work if the person is wearing gloves (2)
gloves are not conductive
gloves block charge from finger
180
Disadvantages of interpreters (2)
longer to execute
translated programs cannot be run without interpreter
181
How do infrared touchscreens work? (5)
infrared rays sent across screen from edges
rays form grid around screen
sensors capture beams
infrared ray broken by finger touching screen
calculation made where beam broken to locate touch
182
Features of interpreters (4)
executes HLL program 1 statement at a time
1 HLL statement = multiple machine code instructions to be executed
does not produce executable file
program cannot run without interpreter
183
Description of NOT gate
triangle with circle in front
184
Disadvantages of high-level language (3)
larger programs
longer - need to wait for program to be translated
program not be able to directly use hardware
185
What if the operating system did not manage memory (4)
data may be lost
applications may produce incorrect result based on wrong data
security issues - incorrect data placement in memory location
computer could crash
186
Define HTML structure
layout of webpage
187
3 groups of memory storage devices
Primary memory
Secondary storage
Offline storage
188
Function of PC
stores address where next instruction to be read can be found
189
How interpreters react to error
stops execution
190
Define a web browser (3)
software
interprets HTML sent from websites
then produces results on screen
191
Lossy file compression examples (3)
Mp3
MP4
JPEG
192
Characteristics of robot (4)
programmable
have mechanical structure
has electrical components
have degree of movement
193
Define internet (2)
worldwide collection of connected networks
uses TCP and IP
194
Advantages of an automated systems (4)
faster
safer
likely to run under optimum condition
less expensive in long run
195
Description of proximity sensor
detect presence of nearby object
196
Define the file name in a URL
item on web page
197
Examples of what is stored in primary memory (2)
BIOS
start-up instructions
198
Define machine learning (2)
training computers with sample data so they can make predictions on unseen data
algorithms learning from past experiences
199
How 3D scanners work (3)
object has x,y coordinates
scans along coordinates
scanned image used by CAD
200
Equation for size of mono sound file
sample rate (Hz) x sample resolution (bits) x sample length (seconds)
201
Define HTML webpage
formatting of webpage
202
Define static IP addresses (2)
permanently assigned to device by ISP
do not change
203
Advantages of inkjet printer (3)
Cheap to initially purchase
high quality output
relatively quiet
204
Advantages of low-level language (4)
can use hardware
performs task quickly
able to access RAM + registers
code doesn't take much primary memory
205
Format of URL
protocol://website address/path/file name
206
How do capacitive touchscreens work (4)
electric fields created between glass layers
sensors monitor electric field
touched = electrostatic charge transferred to finger
location of touch calculated
207
XOR gate rule
output = 1 if input A is 1 AND input B is 0 OR input A is 0 AND input B is 1
208
NAND gate rule
output = 1 if both input = 0
209
Define knowledge base (2)
stores knowledge on area of expertise
repository of facts
210
Cloud storage benefits (5)
file can be accessed as long as there is internet
customer does not need same computer or to carry external storage device with them
cloud provides back-up
cloud storage can recover data
cloud offers almost unlimited storage capacity
211
Benefit of LCD projector (3)
uses less power
higher resolution
runs quiter
212
Data in trailer (2)
method of identifying end of packet
error checking
213
How cookies work on websites (2)
website checks if browser has set cookies before
if does browser reads cookie on user preferences
214
Features of session cookies (4)
stored in temporary memory
doesn't identify user
doesn't exist once browser/website closed
collects info about user's interaction with site
215
Define expert systems (2)
form of AI
mimic human knowledge
216
How is fragmentation caused (3)
HDD becomes full
files become deleted/partially deleted/extended over time
blocks for files become scattered all over surface
217
How does asymmetric encryption work (5)
uses private and public keys
public key sent to sender
sender encrypts document
sender sends cipher text to receiver
receiver uses private key to decrypt
218
Function of control unit (2)
decodes instructions
sends signals to other components telling them what to do
219
Features of system software (4)
programs that control hardware operation
provides services which computer requires
provide platform which other software can run
allow hardware and software to run without problem
220
Solutions to data being accidentally deleted (2)
verification for data deletion
limit people who can delete data
221
What technology does HDD use
magnetic
222
Disadvantages of compilers
harder to debug - produces error report
223
Why HTML presentation is separate from structure (2)
presentation can be changed without affecting structure
presentation can be used for different webpage
224
Features of high-level languages (4)
programming language - converts to machine code using translator
is portable
designed with programmer in mind
one line of code can perform multiple commands
225
Define user interface
allows user and expert system to interacts
226
Define a URL
text address to access websites
227
Features of asynchronous data transmission (3)
data transmitted in agreed bit pattern
data bits grouped together and sent with control bits
receiver of data knows when data starts/ends
228
Features of low-level language (3)
programming language
dependent on hardware
refer to machine code, binary, assembly language
229
3 types of technology for secondary (and off-line) storage (3)
magnetic
solid state
optical
230
Define 2 step verification (2)
authentication
uses 2 methods to verify users
231
How checksum works (6)
checksum calculated from data block using algorithm
checksum transmitted with data block
checksum recalculated by receiver using same algorithm
original checksum compared with calculated checksum
checksum equal = no change
if not = request to resend data
232
Examples of optical storage devices (2)
CDs
DVDs
233
Examples of application software (4)
photo editing
video editing
word processor
spreadsheet
234
AND gate rule
output = 1 if both inputs = 1
235
Examples of operating systems (2)
Microsoft Windows
Google Android
236
Define an interrupt (2)
signal sent from device/software to microprocessor
causes microprocessor to stop what it is doing + address the more urgent problem
237
NOT gate rule
output = 1 if input = 0
238
Define rule base (2)
set of rules for inference engine
use logical thinking draw conclusions (IF statements)
239
Description of AND gate
curved rectangle
240
How do resistive touchscreens work (5)
uses multiple layers of material
transmits electric currents
when touched, top layer pushed into bottom layer
electric current changes
location of touch found
241
Define a compiler (2)
program which translates program written in high-level language to machine code
can be directly used by computer to perform task
242
Description of acoustic/sound sensors
microphones that convert sound into electric signals
243
Examples of digital currency (2)
Paypal
Credit cards
244
Main characteristics of AI (4)
collects data
has rules for using that data
ability to reason
ability to learn/adapt
245
Function of primary memory
allows CPU to access applications/services temporarily stored in memory locations
246
LED benefits (3)
consumes less power
has bright screen/colours
lasts long
247
Example of domain host
www
248
Examples of causes of interrupts (3)
input/output process
hardware/software fault
user interaction - keyboard
249
Ethical issues with distributing and developing software (4)
Plagiarism
Offensive material
privacy of data
production of malware
250
Examples of external secondary storage (4)
DVD
CD
Blu-ray disk
USB
251
Features of adware
floods user with unwanted advertising
252
Function of cookies (3)
track user preferences
hold items in online shopping cart
store login details
253
How interrupt is serviced (3)
status of current task saved - contents in PC + other registers saved
Interrupt service routine executed by loading start address into PC
interrupt has been serviced = contents of saved registers retrieved + interrupted task continued
254
7 mark sensor answer (7)
Sensor name
Sensor send signal which converts analogue to digital using ADC
Microprocessor compares digital value (ADC value) with stored value (in the question)
If it's within range nothing happens
If it's outside ange signal is sent to actuator
does something (according to question)
system operates in a continuous loop
255
How is a webpage requested (8)
user enters URL in address bar
browser asks DNS server for website IP address
DNS sends matching IP address to user computer
required pages downloaded onto HTML files
server sends HTML files to browser
browser interprets HTML
website displayed on screen
256
Functions of web browsers (4)
bookmark websites
store user history
store cookies
allowing use of multiple tabs
257
Equation for file size of image
image resolution (pixels) x colour depth (bits)
258
3 types of translators (3)
compiler
Interpreter
Assembler
259
Disadvantages of infrared touchscreens (3)
sensitive to moisture
sensitive to light interference
accidental activation if infrared disturbed
260
SRAM and DRAM differences (6)
SRAM more expensive
SRAM uses more power
DRAM for main memory while SRAM for cache
SRAM faster
DRAM stores more bits per chip
DRAM needs to be recharged to maintain data while SRAM holds data as long as there is power
