Everything 1 Flashcards
What do computers do to data?
process it
_____ is the basic building block of all computers
binary
What is a microprocessor?
Same role as CPU but smaller scale // usually for a specific task // AKA embedded system // example are traffic lights, digital alarm clocks
What’s a CPU?
Central processing unit // performs thousands of tasks and complex instructions // example smartphones or laptops
What’s von Neumann architecture?
CPU access memory directly // memory stores programs and data // programs are series of instructions carried out in order
What is the fetch decode execute cycle?
Everytime a computer performs a task or runs a program it runs the FDE cycle // Fetches the instruction into the CPU // CPU decodes the instruction // Instruction is executed by CPU
What happens in the fetch step of FDE cycle?
PC contains address of memory location of next instruction // address is copied from PC to MAR via address bus // instruction at address contained in MAR temporarily copied to MDR using data bus // instruction of MDR copied into CIR // PC incrememts by 1, points to next instruction // instruction gets decoded then executed by signals via control bus to other parts of the computer
FETCH - What happens after the PC gets first instruction?
Address copied from PC to MAR
FETCH - What happens after MAR receives instruction via address bus?
Instruction copied to MDR
FETCH - Where do instructions go after MDR?
CIR
When instructions are executed by CPU, what component performs maths and logic calculations?
Arithmetic Logic Unit (ALU)
What’s the ALU’s special register for storing interim calculations called?
Accumulator (ACC)
Name 3 types of buses in CPU
data bus, control bus, address bus
What does the CIR do?
stores the current instructions being decoded and executed
What does the MAR do? (Memory address register)
stores the address of the memory location currently being read from/written to
What does the MDR do? (Memory data register)
stores data which has just been read from memory/data and is about to be written to memory
What does the PC do? (program counter)
stores the address where the next instruction to be read can be found
What does the CU do? (control unit)
sends control signals that manages the execution of instructions in the cpu
Describe the address bus
Carries addresses throughout the computer (unidirectional)
Describe the data bus
Alllows data to be sent through the computer (bi-directional)
Describe the control bus
Carries signals from the control unit to all other components (bi-directional)
Another name for RAM is
IAS Immediate Access Store
Convert 12 to binary?
1100
Convert 23 to binary
10111
Convert 43 to binary
101011
Convert 62 to binary
111110
Convert 15 to binary
1111
Convert 8 to binary
1000
Convert 0110 to denary
6
Convert 01101 to denary
13
Convert 101010 to denary
42
Convert 11111 to denary
31
Convert 1011101 to denary
93
Convert 6 to binary
110
What are the 8 bit binary placeholders?
128 / 64 / 32 / 16 / 8 / 4 / 2 / 1
What are the 12 bit binary placeholders?
2048 / 1024 / 512 / 256 / 128 / 64 / 32 / 16 / 8 / 4 / 2 / 1
Hexadecimal is base ___
16
Example of a 4 digit Hex number
A23F or 12FF or 79BB etc
_________ is base 16
hexadecimal
In hexadecimal A to F represent…
A = 10, B = 11, C = 12, D = 13, E = 14, F = 15
How to convert hex to denary?
Convert to hex to binary -> binary to denary
How to convert denary to hex?
Convert denary to binary -> binary to hex
Convert A0 to binary
1010000
Convert 1C to binary
0001 1100
Convert 50 (hex) to binary
0101 0000
Convert AA to binary
10101010
Convert A00 to binary
1010 0000 0000
Convert 1001 1011 to hex
9B
Convert 1100 1010 to hex
CA
What does the system clock do?
Defines the clock cycle that synchronises all computer operations
Which bus transmits timing signals ensuring sychronisation?
Control bus
What defines the clock cycle that synchronises all computer operations?
System clock
What happens if you increase clock speed?
Processing speed is also increased - but NOT NECESSARILY overall performance
3.5 Ghz is equivalent to
3.5 billion clock cycles per second
What hardware factors improve overall performance of a computer?
Number of cores, size of cache and speed of clock can affect performance of CPU
How do you increase processor speed (but not necessarily overall performance)?
Increase clock speed
What happens if you increase Number of cores, size of cache and speed of clock?
Improve overall computer performance
Increasing clock speed is known as
overclocking
Overclocking higher than design limits leads to…
unsynchronised operations, crashing, overheating of CPU
If your computer has unsynchronised operations, crashing and overheating of CPU, what might be the cause?
Overclocking
Unlike RAM, cache memory is located in
the CPU
Cache memory has ______ access times than RAM
faster
What has faster access times than RAM
cache memory
What does cache memory store?
frequently used instructions and data
When a CPU wants to check memory, it checks ______ first then _____
cache first, then RAM
Larger cache memory =
better CPU performance
The use of a different number of ______ can improve computer performance
cores
One core is made up of an ____ , ____ ___ and _______
ALU, control unit and registers
What’s made up of an ALU, control unit and registers?
A core
Using more cores means less need to increase ______ ________
increase clock speed
What’s a factor in increasing the number of cores?
CPU needs to communicate with each one which can reduce performance
Unicode and ASCII code are _________ _____
character sets
What represent letters numbers and characters found on a standard keyboard?
Unicode or ASCII
Whats a disadvantage of ASCII?
Not suitable for most languages around the world
What character set code can represent all languages of the world?
Unicode
Unicode is…
universal, efficient, uniform, unambiguous, supports up to 4 bytes per character
Each sound wave has F______, W________, A___________
frequency, wavelength, amplitude
Amplitude =
loudness of sound
Frequency, wavelength and amplitude make up _______
sound waves
Sound is a____________
analogue
Sound waves need to be __________ to be stored in a computer
sampled
Sampling means measuring the ____________
amplitude
Sound conversion is done using
ADC (analogue to digital converter)
Sound waves cannot be measured precisely, so amplitude values are __________
approximate
Sampling happens at
regular time intervals
bits per sample =
sampling resolution / bit depth
Sampling rate =
number of samples per second (in hertz, Hz)
How is sampling used to record a sound clip?
amplitude is determined with sampling rate, each sample encoded as series of binary digits
Using more bits to sample amplitude =
more accuracy of sampled sound
Higher sampling rate or larger resolution =
better quality sound, larger file size
Name 3 drawbacks of larger sampling resolution when recording sound
larger file size, takes longer to transmit/download data, requires greater processing power
Name 3 benefits of larger sampling resolution when recording sound
larger dynamic range, better sound quality, less sound distortion
What has 16-bit sampling resolution and 44.1kHz sample rate?
CDs
Bitmap images are made of
pixels
pixel =
picture element
Each image is made up of a _________ matrix of pixels
two dimensional
Pixels are represented in
binary
Bitmaps are stored as a series of
binary numbers
Black and white images only require ______ per pixel
1 bit
In 2 bit pixels, each pixel can be
1 of four colours
Number of bits used to represent each colour is called
colour depth
8 bit colour depth means each pixel can be _____ colours
256
Modern computers have ___ bit colour depth
24
Image resolution means
number of pixels that make up an image
Lower image resolution means
Less image detail
Pixelated means
Fewer pixels to represent the image
Whats the main drawback of using high resolution images?
Increase in file size
URLs are made up of p_______, d_____ n_____ and w__ p_____ name
protocol, domain name and web page name
What are protocol, domain name and web page name part of?
URLs
What’s the first thing a user has to use to open a webpage
Browser
To get to a web page from a browser, you need to
type or click a link
What does DNS mean?
Domain Name Server
What does a DNS do?
Matches a URL to an IP address
What’s an example of an IPv4 address?
192.158.29.2
Why do we have URLs and IP addresses
Lots of IP addresses are too hard for humans to remember
What’s this? e.g. 192.464.55.2
IPv4 address
What’s an IP address?
Address of a computer on a network
What’s the address of a computer on a network?
IP address
What happens after the DNS has matched the URL to the IP address?
DNS sends IP address to browser
When the browser has the IP address, what happens next?
Requests data from the web server
What does a web server do?
Holds all the files and data for a web page
What holds all the files and data for a web page?
Web server
What does the web server do when it receives a request?
Sends the website data to the browser
What does a browser do?
Converts HTML code into text and images we can understand
What converts HTML code into text and images we can understand
Browsers
What requests data from a web server?
Browser
What’s an example of a browser?
Chrome, Safari, Edge, Firefox
What sends the website data to a browser?
Web server
How to calculate size of image file?
multiply image resolution and colour depth
How to calculate size of sound file?
multiply sample rate , resolution and length of track
How to calculate image resolution?
Multiply height by width in pixels
The output X is 1 if, input A is 1 AND input B is 0, or, input A is 0 AND input B is 1
XOR
The output X is 1 if, neither input A or B or both, are 1
NOR
The output X is 1 if, input A AND input B are NOT both 1
NAND
The output X is 1 if, both inputs A and B are 1
AND
The output X is 1 if, either input A or B, or both, are 1
OR
The output X is 1 if, the input A is 0
NOT
______ ______ check the output of a logic circuit
truth tables
What are cookies?
A text file (stored by web browser) that contains data about a user’s browsing habits/details/preferences
Everytime a user visits a website, the site checks if it has set _______ on their ________ before
Everytime a user visits a website, the site checks if it has set cookies on their browser before
What are small files or code sent from a webserver and stored on a users computer
Cookies
What are the two types of cookies?
Session and persistent
What are session and persistent types of ?
Cookie
Which cookie is temporary and don’t collect or store user information?
Session cookies
Name two facts about session cookies
Temporary, don’t store/collect user info
Which cookies cease to exist when a browser is closed?
Session cookies
Session cookies _____ to ______ when a browser is closed
cease to exist
What are session cookies used for?
Temporary shopping baskets
Which cookies are used for temporary shopping baskets?
Session cookies
____ cookies are stored on the hard drive of a users computer
persistent cookies
Which cookies have an expiry date or stay until deleted?
persistent cookies
Which cookies remain even after the browser is closed?
persistent cookies
What are persistant cookies used for?
Allow website to remember usernames, passwords, emails, baskets, preferences
What kind of user preferences do cookies hold?
language, currency, login
Describe data transmission
Signals transmitted from one device to another
Data transmission can either be over
long distance or short distance
Example of short distance data transmission
computer to printer over USB cable connection
Example of long distance data transmission
One computer to another in a global network (i.e. internet)
What are the 3 factors for data transmission to happen?
Direction of transmission, method of transmission and method of synchronisation
What is simplex
data sent in one direction only, example is computer to printer
What is half-duplex?
both directions but NOT at the same time, example is walkie-talkie
What is full-duplex?
Both directions at the same time, example is telephone call or online gaming
Both directions at the same time describes what?
Full-duplex data transmission
Both directions NOT at the same time describes what?
Half-duplex data transmission
One direction only describes what?
Simplex data transmission
Serial data transmission is…
when data sent one bit at a time over a single wire or channel. bits are sent one after another
Bit sent one after another, over a single wire or channel, one bit at a time describes what?
serial data transmission
serial data transmission can be ….
simplex, half-duplex or full-duplex
Serial advantages and disadvantages
Works well over long distance, data arrives synchronised. BUT slow.
Example of serial data transmission
computer to printer via USB
Parallel data transmission is…
several bits of data (usually a byte) sent down several wires or channels at the same time. Each wire transmits one bit.
Parallel data transmission can be…
simplex, half-duplex or full-duplex
Parallel data transmission advantages and disadvantages
works well over short distances. Fast. BUT over long distances data can become skewed and arrive out of order.
Example of parallel data transmission
Internal circuits in a computer
What does PDLC mean?
Programming development life cycle
What is the PDLC?
Steps that are followed when developing a program (e.g. smartphone app or website)
What are the steps in the PDLC?
Analysis / Design / Coding / Testing
In the PDLC - what is analysis?
First step, the process of understanding what exactly you need as inputs to ‘build’ your product and if you have enough resources.
In the PDLC - what is design?
Second step refers to thinking about the technical and visual aspects of your product.
In the PDLC - what is coding?
Third step, programming
In the PDLC - what is testing?
Testing a product to make sure it works as intended
In programming, what is the name for the process of hiding complex details and showing only what is necessary?
abstraction
In programming, What is the name of the process of splitting a problem into smaller, manageable chunks?
decomposition
What does abstraction mean?
the process of hiding complex details and showing only what is necessary
What does decomposition mean?
the process of splitting a problem into smaller, manageable chunks
What are the 3 parts that make up analysis?
decomposition, analysis, requirements identification
What is the name used for the specific needs of a problem that must be identified as part of the problem analysis?
requirements
Requirements dictate the ______ ______ to a program.
essential inputs
The design process involves which representations?
structure diagrams, flowcharts, pseudocode
Whare are structure diagrams?
Structure diagrams are used to represent sub-systems that make up a system. Each sub-system is also split into smaller sub-systems.
What are flowcharts?
Flowcharts indicates the inputs needed (requirements) and the processes to be followed (logic) that lead to the output (final outcome)
In a flowchart, what is the flow line?
Arrow representing control passing between the connected shapes
In a flowchart, what is the process shape?
Represents something being performed or done
In a flowchart, what is a subroutine?
Subroutine call that will relate to a separate flowchart
In a flowchart, what is an input/output?
Input or output of something into our out of the flowchart
In a flowchart, what is a decision?
A decision (yes/no, true/false) that results in two lines representing different outcomes
In a flowchart, what is a terminator?
Start and stop of process
Facts about pseudocode
Resembles code but can’t be understood by a computer // written for humans // easier for programmers to write and share since close to real code
Coding phase of PDLC is also referred to as
implementation phase, because implements design from previous stage
Program code is usually written in ____
IDE (integrated development environment)
Advantages of IDEs
Adds colour coding and indents to help organise code // helps identify errors using debugger // supports many programming languages
Examples of IDEs
Apache Netbeans, BlueJ and Microsoft Visual Studio Code
What does iterative mean?
Any action that’s carried out in a loop until it produces correct outcome
Iterative testing is useful because…
makes sure each section of code works as intended
What’s the difference between alpha and beta testing?
Alpha is testing it by yourself, Beta is testing on a target audience
____ testing is testing it by yourself, ______ is testing on a target audience
Alpha is testing it by yourself, Beta is testing on a target audience
Why is test data important?
Make sure the product works as intended
Normal data
Data within an accepted range
Boundary data
Values in upper and lower bounds - pair that’s accepted, pair that’s rejected
Extreme data
Data at upper and lower bounds (accepted)
Abnormal data
Any data that is not accepted
What are the 4 basic sub-systems that make up a computer system?
input / process / output / storage
Input / process / output / storage are…
the basic sub-systems that make up a computer system
Binary logical shifts mean
moving a binary number to the left or right in the table
A left logical shift means ________ the number by 2
multiplying
A right logical shift means ________ the number by 2
dividing
During logical shifts, empty positions are filled with
zeros
Left shift this binary number 1 place: 0010 «_space;1
100
Left shift this binary number 2 places: 0010 «_space;2
1000
Right shift this binary number 1 place: 1011»_space;> 1
101
Right shift this binary number 3 places: 1011»_space;> 3
1
Two’s complement allows
representing negative integers
In two’s complement the left-most bit is changed to a _____ value
negative
The left most value is changed to a negative number in _____ _________
two’s complement
Apply two’s complement to 1010
-6
Why does compression exist?
To reduce the size of the file
What’s the impact of compressing files?
less bandwidth required, less storage space required, shorter transmission time
What are the two types of compression?
Lossless and lossy
_______ and _______ are the two types of compression
Lossless and lossy
Lossless and lossy are types of _________
compression
What’s lossy file compression?
compression algorithm eliminates unnecessary data by permanently removing it. original file cannot be reconstructed
Which compression type? Compression algorithm eliminates unnecessary data by permanently removing it. original file cannot be reconstructed
Lossy
Examples of lossy file compression?
images - jpeg, audio - mp3, video - mp4
What are these file types examples of? images - jpeg, audio - mp3, video - mp4
lossy file compression
What’s lossless file compression?
Uses compression algorithm, ALL data from original can be retrieved
What compression type? Uses compression algorithm, ALL data from original can be retrieved
Lossless
What is an example of lossless compression algorithm?
Run length encoding (RLE)
What’s RLE?
Lossless compression algorithm
How do lossless compression algorithms work?
Reduce size of string of identical adjacent data, only effective if repeated patterns/words used
What compression algorithm, reduces size of string of identical adjacent data and is only effective if repeated patterns/words used?
Lossless compression / RLE
USB
Universal Serial Bus
How is data transmitted by USB
Uses serial data transmission / sending data to and from peripherals or devices.
What are advantages of USBs?
simple interface - cable only works one way so less chance of errors // relatively high speed data transfer // universal - lots of devices use USB // can be used for power // automatically detected by computer to transfer
What happens when you plug a USB into a computer?
Automatically detected - if it’s the first time, a driver is downloaded, otherwise it works without needing to download each time
What are disadvantages of USBs?
Cables are limited to 5m usually // not as fast as other cables e.g. network cables
Why are USB cables limited to 5m usually?
More chance of errors in data transmission over long distances
What software is needed when a device is plugged in via USB?
Device driver
USB allows both _____ and ______ data transmission
full duplex and half duplex
Why can a computer only process binary data?
Because it consists of logic circuits/gates that can only process data in two states
Because computers consist of logic circuits/gates that can only process data in two states, computers can only process b______ d______
Because computers consist of logic circuits/gates that can only process data in two states, computers can only process binary data
In computer systems, what is an instruction?
A set of operations decoded in sequence
What is a set of operations decoded in sequence?
Instructions
In computer systems, what does each operation instruct?
ALU and CU
Operations are made up of ________ and ________
opcode and operand
Opcode
informs the CPU what operation needs to be done
Operand
Data which needs to be acted on OR refer to register in memory
What is an instruction set?
A list of all the commands that can be processed by a CPU and the commands are machine code
All software running on a computer contains….
a set of instructions
The ____ _____ ____ cycle is the sequence of steps to process each instruction
Fetch decode execute
Example instruction set is
X86
Instruction sets are written in _______ ____
machine code
machine code is a ____ level language
low
What are embedded systems?
An embedded system is used to perform a dedicated function
What are examples of embedded systems?
e.g. domestic appliances, cars, security systems, lighting systems or vending machines
What is a general purpose computer?
is used to perform many different functions
What is an example of a general purpose computer
e.g. a personal computer (PC) or a laptop
What’s a microcontroller?
has a cpu, ram and rom all embedded onto one single chip to carry out a single task
What has a cpu, ram and rom all embedded onto a single chip to carry out a single task
microcontroller
What’s a microprocessor?
Integrated circuit, ONLY has CPU
What’s system on chips (SoC)?
microcontroller, ports and secondary storage
Advantages of embedded systems?
small, cheap, dedicated to a task, low-power, remote control, fast, reliable
Disadvantages of embedded systems?
difficult to upgrade or troubleshoot, interface confusing, open to hacking, encourages disposing of them
Embedded systems include ____, ____ _______ and ________
inputs, user interface and output (e.g. AC panel, input is buttons, user interface is display, output is air)
Explain embedded system of vending machine
input is buttons, user interface is display, output is actuator which pushes food
What is the purpose of encryption?
There’s always a risk of interception when transmitting data over a public network, encryption reduces the risk
What does encryption mean?
Encryption alters the data into a form that is unreadable by anybody for whom the data is not intended
asymmetric encryption includes the use of _____ and _____ keys
public and private keys
Which encryption method uses public and private keys?
assymetric
What’s plaintext?
the original data being sent
What’s ciphertext?
Plaintext after it goes through encryption algorithm
In encryption, what’s the original data being sent?
plaintext
In encryption, what’s the encrypted data called?
ciphertext
To increase encryption security you…
increase the number of bits used in the key (e.g. 128 bits instead of 64)
Symmetric uses….
The same key for encrypting and decrypting
Which encryption method uses the same key for encrypting and decrypting?
symmetric
Disadvantage of symmetric encryption?
Uses same key for encrypting and decrypting
Scrambles data for secure transmission
encryption
Why is encryption effective?
If the data is stolen it’s meaningless
How does symmetric encryption work?
Same key used for encrypting and decrypting- sender and receiver both need it
How does asymmetric encryption work?
Matching public and private keys are generated that are mathematically linked. Only public key sent. Both needed to decrypt.
What is robotics?
branch of computer science - brings together design, construction and operation of robots
Where can you find robots?
Factory equipment/domestic robots/drones
Examples of factory equipment robots are…
welding parts together, spray painting, fitting windscreens to cards, cutting metal parts, bottling and labelling objects, warehouse operations
Examples of domestic robots are…
autonomous floor sweepers, autonomous lawn mowers, ironing robots, pool clearning, automatic window cleaners, entertainment (robot friends)
Examples of drones are…
UAVs, reconnaisance (photos), parcel delivery
What are the 3 characteristics of a robot?
Sense surroundings, degree of movement, programmable
Explain how robots sense surroundings
sensors allow robot to recognise immediate environment and give it ability to determine things like shape, size, weight of objects
What are examples of sensors robots use?
light, pressure, temperature, acoustic
Explain movement in robots
make use of wheels, cogs, pistons to carry out functions such as twisting, turning, moving, gripping or lifting // they are mechanical structures made up of many parts // contain electrical components // can make use of effectors
What are examples of end effectors in robots?
welding, spraying, cutting, lifting
What determines action to be taken in a robot?
controller
Controllers in robots allow…
action to be taken to perform a task. Controllers rely on sensors/cameras for data and are programmable
In robots, what rely on sensors/cameras for data and are programmable?
controllers
What are examples of software robots (bots?)
webcrawlers, search engines, chatbots
What are the two types of physical robots?
independent and dependent
Explain independent (physical) robots
have no direct human control, autonomous, can replace the human activity totally, no human interaction required for full function
What’s an example of a independent robot?
robot vacuum cleaner
Explain dependent (physical) robots
has a human interfacing with the robot directly, can supplement, rather than replace human activity
What’s an example of a dependent robot?
car assembly plant where humans and robots work together
What are types of AI?
image recognition, speech recognition, natural language, computer games, diagnostic systems
What is image recognition?
identify objects or people in an image
What is speech recognition?
Identify words spoken by humans and store them
What is natural language?
To receive a command or instruction that is not in a set format and perform the required task (e.g. Siri question)
What use is AI in computer games?
to move elements or characters independently based on the environment
What is a diagnosis system in AI?
e.g. to diagnose medical problems
What are the features of AI programs?
collect data, programmed rules, ability to reason, ability to learn and adapt
What is collecting data in AI?
programs need data input - data might come from users or from sensors
What are programmed rules in AI?
Programs use rules to make decisions
What is the ability to reason in AI?
An area of logic. In logic you have rules and can develop facts
What is the ability to adapt and learn in AI?
Not all AI does this, its known as machine learning and requires training a program
What is an expert system?
An attempt to emulate the expertise of a human, e.g. doctor or engineer
How do expert systems work?
System asks questions to determine the solution, depending on answers given it will ask different questions
What’s an example of an online expert system?
Online chat bot to help you with a problem
What are the features of expert systems?
Knowledge base, rule base, inference engine, user interface
In expert systems, what’s a knowledge base?
list of facts
In expert systems, what’s a rule base?
Links the facts
In expert systems, what’s an inference engine?
Decides which question to ask next or which answer it gives
In expert systems, what’s a user interface?
Outputs questions and other statements to the user and allows them to enter data
What is machine learning?
A system that has the ability to learn and adapt, and change their own rules and logic. It involves training.
What is supervised machine learning?
Supervised means that user is telling the program what its data means.
What is unsupervised machine learning?
Unsupervised means that data is input, and then the program learns from the data.
What’s system software
Services a computer requires
What are services a computer requires called?
system software
What are services that a user requires called?
Application software
Examples of system software
operating system, utility programs, device drivers
Examples of application software
spreadsheets, word processors, instagram app, browsers
What are spreadsheets, word processors, youtube app examples of?
application software
What are operating systems, utility programs, device drivers examples of?
system software
general features of system software
control and manage operation of hardware, HCI, allows hardware and software to run without problems, platform on which other sofware can run
general features of application software
perform variety of tasks, applications, apps / users can perform specific tasks / can be single programs / users can execute as required
Features of operating systems
run in background, allows input/output operations, users can interact with hardware, handles errors, loads and runs programs, manages security
features of utility programs
manage and maintain computer resources, designed to carry out specific task, e.g. anti-virus, backups, disk repair
features of device drivers
enables hardware to communicate with operating system
What is firmware?
program that provides low-level control for devices
BIOS
Basic Input Output System (Firmware)
Firmware is run on h_______
hardware
Applications are run on the o________ s______
operating system
Operating system is run on f________
firmware
Bootloader is another name for f
firmware
Bootloading also known as b_________
booting
What is an IDE?
Integrated Development Environment is use to help write computer programs
What do programmers use to help write programs?
IDEs
What are examples of IDEs
Pycharm (for Python), Visual Studio (for Visual Basic)
What are Pycharm (for Python), Visual Studio (for Visual Basic) examples of?
IDEs
What are the features of IDEs?
code editor, translator, runtime environment with debugger, error diagnostics, autocomplete, autocorrect, pretty printing
What are these features of…code editor, translator, runtime environment with debugger, error diagnostics, autocomplete, autocorrect, pretty printing?
IDEs
Describe an IDE code editor
Allows program to be written without using a separate text editor, which makes programming faster
Describe a runtime environment with a debugger in an IDE
Allows programmer to run a program a line at a time and check for errors.
Describe error diagnostics in an IDE
Finds possible errors as the code is being typed
Describe pretty printing in an IDE
Colour codes the words in the program and lays it out in a meaningful way
What colour codes words in a program and lays it out in a meaningful way?
Pretty printing
What is an interrupt?
A signal to the processor to tell it something needs it attention. Can be software or hardware based
What is a signal to the processor to tell it something needs it attention. Can be software or hardware based.
Interrupt
Examples of software interrupts
divide by zero, two processes attempting to access the same memory location, program request for input
What are divide by zero, two processes attempting to access the same memory location, program request for input, examples of?
Software interrupts
Examples of hardware interrupts
Error from hardware e.g. printer out of paper, new hardware device conected
What are error from hardware e.g. printer out of paper, new hardware device conected , examples of?
Hardware interrupts
How does a computer decide the priority of an interrupt to service the interruption?
Managed by an interrupt handler
What does an interrupt handler do?
Decides the priority of interrupts and what to service first
What happens when an interrupt is sent to the processor?
Processor store the current process and fetches the interrupt // Next, checks the source of the interrupt // Calls the relevant Interrupt service routine to handle it // When finished the stored process is returned to memory
The internet can be described as….
an infrastructure
An infrastructure is a way of describing
the internet
An infrastructure means all…
parts are connected in a huge network
All parts connected in a huge network is called an
infrastructure
What can you do on the internet?
send/receive emails, chatting (video, text, audio), share files
What makes use of transmission protocols (TP) and internet protocols (IP)
The internet
What is a world wide collection of internet connected networks and devices?
The internet
The internet uses transmission _________ and internet ___________
protocols
URL
uniform resource locator
URLs are made up of 3 things….
protocol, domain, webpage
Protocol, domain and webpage are part of….
URLs
Every website and webpage has a
URL
What’s a text address used to access websites?
URL
HTTP means
Hyper text transfer protocol
www.google.com is made up of…
domain host (www), domain name (Google ), domain type (.com)
URLs consist of
protocol://website address /path/filename
In a URL the protocol is…
http or https
In a URL the domain name is broken into 3 pieces…
domain host (www), domain name (name e.g. Google, Youtube), domain type (e.g. .com .gov. kr)
HTTP is secure if
is HTTPS
URLs are t_____ addresses to access websites
URLs are text addresses to access websites
HTTP means H_____T_____ T_____ P_______
HyperText Transfer Protocol
Another sign that a website is secure, other than HTTPS protocol is…
Padlock in the address bar
A padlock in the address bar next to HTTPS means
Site is secure
Web browsers are…
software that allows users to access and display web pages on their devices
Browsers translate ______ to images, video, text and audio
HTML
What do browsers translate HTML into?
images, video, text and audio
What is software that allows users to access and display web pages on their devices?
Web browsers
Most browsers have what features?
Home page, favourites/bookmarks, history, tabs, use cookies, use links, have an address bar
What are these features of - Home page, favourites/bookmarks, history, tabs, use cookies, use links, have an address bar
Web browsers
Name 5 browsers
Chrome, Edge, Safari, Firefox, Opera
What are Chrome, edge, safari, firefox, opera examples of?
Browsers
The world wide web the name for
all websites and webpages
All websites and webpages are known as
the world wide web (www)
Websites are a collection of
webpages
A collection of webpages is called
a website
WWW uses what protocol?
HTTP(S)
Web resources are accessed using
web browsers
HTTP(S) protocol is written using
HTML
What is the part of the internet that’s only accessible through web browsers?
World Wide Web
What uses the internet to access information from web servers?
World Wide web
___ resources are accessed by ____ browsers
web / web
Payments can be sent digitally over the internet using…
Paypal, Apple Pay, Kakaopay and more
Digital payments over the internet are secure because they are
Encrypted
The central authority for currencies are
banks
Banks are the ________ _________ for currencies
central authority
An example of a central bank is….
Bank of England, Bank of Korea
Examples of cryptocurrencies are
bitcoin, dogecoin, ethereum, cardano
bitcoin, dogecoin, ethereum, cardano are examples of
cryptocurrencies
Bank of England and Bank of Korea are examples of
central banks
Cryptocurrency has no ________ _________
central authority
What has no central authority for payments?
cryptocurrencies
No central authority is also called
Decentralised
Decentralised
means no central authority
Cryptocurrency payments over the internet are secure because
they are encrypted
Payments are made for cryptocurrencies using…
blockchain
Blockchain is how _________ payments are made
Cryptocurrency
A blockchain is like a
digital ledger or list of all records of payment
Blockchains record…
All payments with time and date stamps
Once added to a blockchain, records….
cannot be changed
Blockchains are accessible by…
every connected computer
USB
Universal Serial Bus
How is data transmitted by USB
Uses serial data transmission / sending data to and from peripherals or devices.
What are advantages of USBs?
simple interface - cable only works one way so less chance of errors // relatively high speed data transfer // universal - lots of devices use USB // can be used for power // automatically detected by computer to transfer
What happens when you plug a USB into a computer?
Automatically detected - if it’s the first time, a driver is downloaded, otherwise it works without needing to download each time
What are disadvantages of USBs?
Cables are limited to 5m usually // not as fast as other cables e.g. network cables
Why are USB cables limited to 5m usually?
More chance of errors in data transmission over long distances
What software is needed when a device is plugged in via USB?
Device driver
USB allows both _____ and ______ data transmission
full duplex and half duplex
Why keep data safe?
It has either personal or business value
Examples of personal information/data?
credit card number, bank account, date of birth, passport number, passwords
Data can be…
corrupted, deleted, or intercepted - maliciously or accidentally
What is a brute force attack?
A hacker tries to crack a password using all combinations of characters
What hacking is when a hacker tries all combinations of characters?
brute force attack
What is a wordlist?
A very large text file containing common words for passwords
Name facts about brute force attacks
No sophistication, time consuming, often uses wordlists
What is data interception?
Stealing data by tapping into wired or wireless communcation links
What is stealing data by tapping into wired or wireless communication links?
Data interception
Wired data interception uses a
packet sniffer
What do packet sniffers do?
Look at packets going over a network
Wireless data interception is also called
wardriving/ access point mapping
What makes wireless data interception harder to do?
If data is encrypted using Wireless Equivalency Privacy (WEP)
DoS
Denial of Service
DDoS
Distributed Denial of Service
What is the purpose of a DoS or DDoS?
Attempt at preventing users from accessing part of a network
DoS or DDoS facts
Usually an internet server, usually temporary, very damaging and large breach of security, can be individual or group target
What is a cyber attack that is..usually an internet server, usually temporary, very damaging and large breach of security, can be individual or group target
DoS or DDoS
What’s the difference between a DoS and DDoS?
DDoS comes from many different computers all around the world
How does a DoS or DDoS work?
Floods a network with spam traffic and web servers can only handle so many requests, so they become overloaded and can’t answer legitimate requests
How can you prevent DoS or DDoS?
Use up to date malware blockers / use firewalls to restrict traffic / use filters to block spam
What are the signs of a DoS or DDoS?
V slow internet on network / can’t access some websites / large amounts of spam
What is meant by phishing?
Creator sends out legitimate looking email; as soon as recipient clicks on a link in the email/attachment, the user is sent to a fake website
What are the effects of phishing?
Loss of personal data such as bank account numbers. Can also lead to identity theft.
How to prevent phishing?
Be aware and cautious when opening emails or attachments. Use anti-phishing software. Look for HTTPS
What’s spear phishing?
Attacks a specific individual to gain access to sensitive information
What’s the difference between phishing and spear phishing?
Spear phishing attacks one person, phishing attacks many
What’s the aim of phishing?
Steal personal data like credit cards and bank information
What is meant by pharming?
vicitim clicks a link and malicious code installed on their computer which redirects to fake website to steal personal information
How do you prevent pharming?
Install anti-malware, don’t click suspicious links
What’s a virus?
Replicates itself, corrupts data
What’s a worm?
Replicates itself, finds weaknesses in networks and slows them down
What’s spyware?
Records actions on a computer
What’s an example of spyware?
Keylogger
What’s a trojan horse?
Used to disguise other malware
What’s adware?
Designed to create advert banners and popups when online
What’s ransomware?
Encrypts data so you can’t access it, creators demand ransom to give it back
What replicates itself, corrupts data?
Viruses
What replicates itself, finds weaknesses in networks and slows them down?
Worms
What records actions on a computer?
Spyware
What’s a keylogger?
Example of spyware
What’s used to disguise other malware?
Trojan horse
What’s designed to create advert banners and popups when online?
Adware
What encrypts data so you can’t access it, creators demand ransom to give it back?
Ransomware
Name three protections against malware
Anti-malware, firewalls, backups
What 3 things does anti-malware do?
Scans, quarantines and deletes any malware found
What’s a firewall?
Helps prevent malware - looks at data coming in and out of a computer
What scans, quarantines and deletes any malware found?
Anti-malware
What helps prevent malware - looks at data coming in and out of a computer?
Firewalls
What looks for spyware?
Anti-spyware
Social engineering is…
When a perpetrator will try and manipulate and deceieve someone into providing them with personal or confidential data
What’s it called when a perpetrator will try and manipulate and deceieve someone into providing them with personal or confidential data?
Social engineering
What’s the aim of social engineering?
To get data to commit criminal activity, such as stealing money, hacking into a computer network, and identity theft or fraud
How can you prevent social engineering?
Access levels to data and staff training of how social engineering works
What is a word list
a text file containing a collection of words used in a brute force attack
What is packet sniffing?
a method used by a cybercriminal to examine data packets being sent over a network and to findthe contents of a data packet, which are sent back to the cybercriminal
What’s wardriving?
using a laptop, antenna, GPS device and software to intercept Wi-Fi signals and illegally obtain data;sometimes called Access Point Mapping
What’s spam?
unsolicited emails sent to a user’s mailbox
What are access levels?
different levels of access in a computer system allowing access depending on the users security level
What’s anti-spyware?
software that detects and removes spyware programs installed on a system; the software is based on typical spyware rules or known file structures
What’s a patch?
An update for software that improves its and/or removes bugs
What’s a SSL certificate?
A form of digital certificate that authenticates a website, and any data transmission between the browser and website is secure
