Everything 1 Flashcards
SRAM =
static RAM
Optical media is also known as
offline storage
NIC =
Network interface card
What are the signs of a DoS or DDoS?
V slow internet on network / can’t access some websites / large amounts of spam
SSDs are also known as
flash memory or flash storage
Abnormal data
Any data that is not accepted
What memory stores data the computer accesses directly
primary memory
Any form of data needs to be converted to ________ format
binary
CDs and DVDs use what colour laser?
red
Secondary storage includes -
HDD and SSD
Floating gates and control gates are found in
transistor junctions for SSDs
What are problems with packet loss
Lost packets accumulate and network slows
What are the 8 bit binary placeholders?
128 / 64 / 32 / 16 / 8 / 4 / 2 / 1
What is stealing data by tapping into wired or wireless communication links?
Data interception
What is latency in HDDs?
Time it takes for block of data to rotate to the head and be read
In a flowchart, what is an input/output?
Input or output of something into our out of the flowchart
FETCH - What happens after MAR receives instruction via address bus?
Instruction copied to MDR
In the PDLC - what is testing?
Testing a product to make sure it works as intended
What is data interception?
Stealing data by tapping into wired or wireless communcation links
DVD-RAM is different because
It has many concentric tracks and acts more like a hard drive
Most common use of DVDs or Blu-rays is
games/movies
HDD =
hard disc drive
Example of parallel data transmission
Internal circuits in a computer
How to convert hex to denary?
Convert to hex to binary -> binary to denary
In the PDLC - what is coding?
Third step, programming
What’s an actuator?
a device that produces motion (e.g. controls wheels, motors, magnets)
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 do we call input devices that take readings and send them to a computer or microprocessor?
sensors
What’s the order of data units from smallest to largest?
bit, nibble, byte, kilobyte, megabyte, gigabyte, terabyte, petabyte
Packet trailer contains
ID of end of packet and error checking (CRC)
video, images, sounds, text, numbers, facts are all forms of
data
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.
One direction only describes what?
Simplex data transmission
The smallest piece of computer memory is a
bit
Which type of RAM has a higher memory capacity?
DRAM
What is a USB port?
A socket in a device/computer that allows you to plug in a cable
Non-volatile, not accessible by the CPU - which storage?
secondary
What are flowcharts?
Flowcharts indicates the inputs needed (requirements) and the processes to be followed (logic) that lead to the output (final outcome)
Which type of RAM is less expensive?
DRAM
A bit is….
the smallest piece of computer memory
How can you prevent DoS or DDoS?
Use up to date malware blockers / use firewalls to restrict traffic / use filters to block spam
Disadvantages of packets/packet switching
Packets can get lost, problems with real time streaming, delay when reassembling at end
What does the MAR do? (Memory address register)
stores the address of the memory location currently being read from/written to
In a flowchart, what is a terminator?
Start and stop of process
Denary counts in multiples of ____
10
Secondary storage can be ______ or _______
secondary storage can be internal or external
Drawbacks of SSDs
longevity, SSD endurance not as good as HDDs // can’t overwrite data, have to delete first then write new
How is data transmitted by USB
Uses serial data transmission / sending data to and from peripherals or devices.
What kinds of USB are there?
USB ports, USB cables, USB connections, USB devices
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 analysis?
First step, the process of understanding what exactly you need as inputs to build your product and if you have enough resources.
Hexadecimal is base ___
16
How many bytes in a kilobyte?
1024 bytes in a kilobyte
stores data that computers need to access when powering up (BIOS or bootstrap)
ROM
How to reduce fragmentation problems in HDDs?
Defragment the hard drive
Convert 8 to binary
1000
NIC contains a ______ address
MAC
8 bits is a
byte
Convert 15 to binary
1111
What does the CU do? (control unit)
manages the execution of each instruction
Floating gates and control gate transistors use what technology?
CMOS (complimentary metal oxide semiconductor) NAND technology
humans experience _________ data
analogue
Program code is usually written in ____
IDE (integrated development environment)
DoS or DDoS facts
Usually an internet server, usually temporary, very damaging and large breach of security, can be individual or group target
Normal data
Data within an accepted range
What are the 3 factors for data transmission to happen?
Direction of transmission, method of transmission and how synchronised
Another name for RAM is
IAS Immediate Access Store
Switch on = ___
1
In optical media laser wavelength determines
storage size - smaller wavelength = more storage
What’s the difference between alpha and beta testing?
Alpha is testing it by yourself, Beta is testing on a target audience
What’s the difference between a DoS and DDoS?
DDoS comes from many different computers all around the world
Example of serial data transmission
computer to printer via USB
All apps, operating systems, files are stored on…
secondary storage
Convert A00 to binary
1010 0000 0000
USB
Universal Serial Bus
Convert 43 to binary
101011
Convert 12 to binary
1100
What’s synchronous data transmission?
Data is sent in a continous stream including timing signals made by an internal clock. Faster than asynchronous but the timing must be accurate. Used in network communication
CPU means
Central processing unit
Examples of optical media are
CDs, DVDs, Blu-rays discs
Convert 50 (hex) to binary
0101 0000
Flash memory includes
SSDs, memory sticks and flash drives
Boundary data
Values in upper and lower bounds - pair that’s accepted, pair that’s rejected
Optical media discs have either _____ or _____ tracks
single or concentric spiral tracks
Convert 62 to binary
111110
Describe the data bus
Carries / transports data / example of data that is currently being processed OR that will be OR that has been processed // Data can travel in both directions (bidirectional)
Which type of RAM uses less power?
DRAM
Denary is used by _____
humans
Why are USB cables limited to 5m usually?
More chance of errors in data transmission over long distances
What are the 12 bit binary placeholders?
2048 / 1024 / 512 / 256 / 128 / 64 / 32 / 16 / 8 / 4 / 2 / 1
Data is stored by moving electrons with NAND and NOR chips
SSDs / flash drives
What’s asynchronous data transmission?
Groups of bits are sent with control bits. A pattern is agreed before sending and data has ‘start’ and ‘end’ bits. Stops data getting mixed during transmission
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.
2 types of MAC addresses are
Universally Administered Address (UAA) and Locally Administrered Address (LAA)
Optical media is used…
for backups, transfer files/media
What are examples of automated systems in real life?
industry, transport, agriculture
Automated systems are made up of
software and hardware (sensors, microprocessors/cpu, actuators)
Which type of RAM is main memory constructed of?
DRAM
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 benefit does dual layer offer blu-ray and DVDs?
more storage
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 are types of red laser optical media?
CD-RW/DVD-RW (write many), CD-R/DVD-R (write once)
What do microprocessors do in automated systems?
process data and perform programmed actions
Which type of RAM has a faster data access time?
SRAM
SSDs have two transistor junctions called
floating gates and control gates
Bit sent one after another, over a single wire or channel, one bit at a time describes what?
serial data transmission
Which type of RAM needs to be constantly refreshed?
DRAM
In programming, what is the name for the process of hiding complex details and showing only what is necessary?
abstraction
Serial advantages and disadvantages
Works well over long distance, data arrives synchronised. BUT slow.
Used to store data, files, part of an application or part of the operating system in use
RAM
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
Binary is made up of ___ and ____ (numbers)
1 and 0
Both directions at the same time describes what?
Full-duplex data transmission
What do computers do to data?
process it
NIC is needed to
allow a device to connect to a network
SSD are solid state because
they have no moving parts
Data is stored in binary as millions of transistors on…
SSDs
What’s a USB connection?
Anything that uses a USB cable plugged into a port
In programming, What is the name of the process of splitting a problem into smaller, manageable chunks?
decomposition
What are the steps in the PDLC?
Analysis / Design / Coding / Testing
What’s a USB cable?
Type of cable that transmits data OR provides power
Binary digit is abbreviated to…
bit
What makes wireless data interception harder to do?
If data is encrypted using Wireless Equivalency Privacy (WEP)
Computers are made up of billions of tiny _______
switches
Why keep data safe?
It has either personal or business value
NICs can be ______ or _______
NICs can be wired or wireless
Packets are usually around ______ in size
64kb
What is full-duplex?
Both directions at the same time, example is broadband internet or online gaming
non-volatile =
contents not lost when power turned off
What are the 3 parts that make up analysis?
decomposition, analysis, requirements identification
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.
How is binary data stored on optical media?
in pits and lands, representing 1s and 0s
Coding phase of PDLC is also referred to as
implementation phase, because implements design from previous stage
What is the name used for the specific needs of a problem that must be identified as part of the problem analysis?
requirements
What is the PDLC?
Steps that are followed when developing a program (e.g. smartphone app or website)
Give a disadvantage of RAM
It’s volatile
permanent memory - contents cannot change or be written to by user/computer/program
ROM
Convert 0110 to denary
6
Primary memory or primary storage includes
RAM and ROM
In optical media data is divided into
sectors
RAM = _______ ________ ________
random access memory
Data is stored on HDDs in ______ and ______
Data is stored on HDDs in sectors and tracks
What storage is not accesible by the CPU?
Secondary
CMOS (complimentary metal oxide semiconductor) NAND technology is used by what storage?
SSD or Flash drives
Iterative testing is useful because…
makes sure each section of code works as intended
What’s a CPU?
Central processing unit // performs thousands of tasks and complex instructions // example smartphones or laptops
contents lost when power turned off
volatile
Packets are used to….
Send data from one device to another over the internet
Advantages of IDEs
Adds colour coding and indents to help organise code // helps identify errors using debugger // supports many programming languages
Software and hardware (sensors, microprocessors/cpu, actuators) are used in
automated systems
Describe the address bus
Carries / transports an address / location of the next item to be fetched // Data travels one way (unidirectional)
Describe the control bus
Carries / transports signals and controls / directs the actions of the CPU / processor // Can be either Unidirectional or Bidirectional
ROM = _______ ________ ________
read only memory
Examples of IDEs
Apache Netbeans, BlueJ and Microsoft Visual Studio Code
Wireless data interception is also called
wardriving/ access point mapping
Which type of RAM doesn’t need to be constantly refreshed?
SRAM
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
Packets are sent along different ________
routes
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
Sensors are
input devices that take readings and send them to a computer or microprocessor
Binary is used by _______
computers
Increasing _____ usually makes your computer run more quickly
RAM
What are disadvantages of USBs?
Cables are limited to 5m usually // not as fast as other cables e.g. network cables
Blu-rays advantages
hold more than DVDs or CDs, faster rate of data transfer, automatically comes with encryption to prevent piracy
HDD uses what kind of storage
magnetic
Benefits of SSDs
more reliable as no moving parts // lighter // lower power // cooler // thinner // faster than HDDs // No disc to spin or ‘get up to speed’
What’s a USB device?
Anything that plugs into a USB port
Which memory is volatile?
RAM
In a flowchart, what is the flow line?
Arrow representing control passing between the connected shapes
What is a wordlist?
A very large text file containing common words for passwords
Two types of RAM are
DRAM and SRAM
Data can be…
corrupted, deleted, or intercepted - maliciously or accidentally
Both directions NOT at the same time describes what?
Half-duplex data transmission
What does secondary storage hold?
All apps, operating systems, files
Data transmission can either be over
long distance or short distance
Examples of personal information/data?
credit card number, bank account, date of birth, passport number, passwords
What is hopping?
Adding a hop number to each packet which reduces by 1 at each router. If number reaches 0, the packet gets deleted
A single 1 or 0 on a computer is called a
bit
Packet headers contain
sender IP address, receiver IP address, sequence number (for reassembly), size in bytes
Optical media tracks…
spiral from the centre to the edge of the disc
Convert A0 to binary
1010000
Magnetic storage includes
HDD
Data is stored on SSDs as
binary in millions of transistors
Convert 11111 to denary
31
Which memory is non-volatile?
ROM
How many bits in a MAC address and how are they grouped?
48 bits, six groups of 2 hex digits
____ is base 10
denary
Blu-ray lasers…
are blue and narrower than CDs or DVDs
What is data transmission?
Signals being sent from one device to another
_________ is base 16
hexadecimal
Removable HDDs are external and connect via
USB cable
HDD is magnetic storage because…
Disc heads are electromagnets and a magnetic field determines the binary value
DVDs and blu-rays can have what layer types?
single or dual
In a flowchart, what is a decision?
A decision (yes/no, true/false) that results in two lines representing different outcomes
What does iterative mean?
Any action that’s carried out in a loop until it produces correct outcome
Switch off = ___
0
What does abstraction mean?
the process of hiding complex details and showing only what is necessary
Advantages of packets/packet switching
Easier to control than a stream of data, packets can go different routes in case route is busy/broken and allows high transmission of data
0 = switch ____
off
Convert AA to binary
10101010
Wired data interception uses a
packet sniffer
Which type of RAM is used by the CPU memory cache?
SRAM
DDoS
Distributed Denial of Service
What does the PC do? (program counter)
stores the address where the next instruction to be read can be found
Give an advantage of RAM over other types of memory
RAM is much faster to write to or read from than other types of memory
What do packet sniffers do?
Look at packets going over a network
What does the CIR do?
stores the current instructions being decoded and executed
Packet payload contains
The actual data (around 64kb)
How does packet switching work?
Each packet broken down at sender, sent independently, route decided by routers, receiver reassembles
serial data transmission can be ….
simplex, half-duplex or full-duplex
How to convert binary to hex
Start right and move left, convert each group of 4 bits. If less than 4 bits, fill in with 0s from left. Take each group of 4 and convert to hex
In hexadecimal A to F represent…
A = 10, B = 11, C = 12, D = 13, E = 14, F = 15
Binary is base __
2
How do you convert binary to denary?
Each time a 1 appears in a binary column, add the heading (value) to the total
Example of a 4 digit Hex number
A23F or 12FF or 79BB etc
What are some problems with HDDs and data?
Data stored gets fragmented which reduces performance // latency
A byte is ____ bits
8
Which type of RAM uses flip flops to hold each bit of memory?
SRAM
_____ is the basic building block of all computers
binary
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
Why is test data important?
Make sure the product works as intended
Convert 1C to binary
0001 1100
Data is read from optical media by
The disc spinning and the disc head uses laser light
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
Data is sent from one device to another using ___________
packets
Which type of RAM consists of transistors and capacitors?
DRAM
How many kilobytes in a megabyte
1024 kilobytes in a megabyte
analogue data is experienced by
humans
DRAM =
dynamic RAM
Primary memory contains ____ _____ and _______________
ram, rom and cache memory
When you run a program data is retrieved from _____ ______ and placed temporarily into ____
When you run a program data is retrieved from secondary storage and placed temporarily into RAM
How to convert denary to hex?
Convert denary to binary -> binary to hex
Requirements dictate the ______ ______ to a program.
essential inputs
SSD and HDD are examples of…
secondary storage
Convert 6 to binary
110
examples of data are…
video, images, sounds, text, numbers, facts
____ is base 2
binary
What needs to be converted into binary before it can be processed by a computer?
data
When instructions are executed by CPU, what component performs maths and logic calculations?
Arithmetic Logic Unit (ALU)
In a flowchart, what is the process shape?
Represents something being performed or done
FETCH - What happens after the PC gets first instruction?
Address copied from PC to MAR
SSD stores data by
moving electrons with NAND and NOR chips
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
DoS
Denial of Service
Convert 1001 1011 to hex
9B
How do cyclic redundancy checks work?
BEFORE SENDING - sender adds together 1 bits in payload and states value as hex in trailer / WHEN RECEIVED - receiver counts 1 bits, if they match accept it, if not request resent
Why does smaller wavelength = more storage in optical media?
smaller pit/land size so more binary data can be stored
What category of storage includes RAM and ROM
Primary
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
What is the purpose of a DoS or DDoS?
Attempt at preventing users from accessing part of a network
What’s the ALU’s special register for storing interim calculations called?
Accumulator (ACC)
Convert 23 to binary
10111
Convert 101010 to denary
42
1 bit is a single
1 or 0
Serial data transmission is…
when data sent one bit at a time over a single wire or channel. bits are sent one after another
What is half-duplex?
both directions but NOT at the same time, example is walkie-talkie
Convert 1011101 to denary
93
Memory that’s directly accessible by the CPU, contains RAM, ROM and cache memory
primary memory
contents not lost when power turned off
non-volatile
What’s von Neumann architecture?
CPU access memory directly // memory stores programs and data // programs are series of instructions carried out in order
volatile =
contents lost when power turned off
Convert 1100 1010 to hex
CA
Example of short distance data transmission
computer to printer
What is a brute force attack?
A hacker tries to crack a password using all combinations of characters
Extreme data
Data at upper and lower bounds (accepted)
How is a MAC address divided?
NN-NN-NN-DD-DD-DD (Manufacturer-Device serial)
Parallel data transmission can be…
simplex, half-duplex or full-duplex
The design process involves which representations?
structure diagrams, flowcharts, pseudocode
Data is read and written to optical media by
laser light
MAC address =
Media Access Control address
What does decomposition mean?
the process of splitting a problem into smaller, manageable chunks
1 = switch ____
on
SSD =
solid state drive
Example of long distance data transmission
One computer to another in a global network (i.e. internet)
Magnetic storage spins discs….
about 7000 rpm
Can be written to or read from and data can be changed by the user or the computer
RAM
Name facts about brute force attacks
No sophistication, time consuming, often uses wordlists
Denary is base __
10
In a flowchart, what is a subroutine?
Subroutine call that will relate to a separate flowchart
What does dual layer mean?
Two layers are sandwiched, one is slightly deeper, DVD/Blu-ray reads both
Name 3 types of buses in CPU
data bus, control bus, address bus
Convert 01101 to denary
13
Magnetic storage stores data on
discs or platters
____ 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
What is simplex
data sent in one direction only, example is computer to printer
What hacking is when a hacker tries all combinations of characters?
brute force attack
FETCH - Where do instructions go after MDR?
CIR
Binary counts in multiples of _______
2
Packets are made up of
Header / Payload (Data) / Trailer
What are the key questions to consider when reviewing automated systems?
What is the system? / What sensors are used? / What do the actuators do? / What does the computer/microprocessor do?
What does PDLC mean?
Programming development life cycle
How do you add two binary numbers?
Write them like column addition sum, start from right side and carry any 1+1 otherwise keep value
What is an overflow error?
When a number is too big to be stored in (value) bits
Maximum number value of 8 bits is
255
Maximum number value of 12 bits is
4096
Maximum number value of 16 bits is
65535
Binary logical shifts mean
moving a number to the left or right
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
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
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
Amplitude =
loudness of sound
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)
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
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
What are cookies?
Small files or code stored on a user’s computer
What are small files or code sent from a webserver and stored on a users computer
Cookies
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 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
Payments can be sent digitally over the internet using…
Credit cards, 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 as 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
A single 1 or 0 is called a
bit
How many bits in a byte?
8
How many bits in a nibble?
4
1 kibibyte = 1 KiB = how many bits?
1024
1 mebibyte = 1MiB = how many KiB?
1024
KiB =
Kibibyte
MiB =
Mebibyte
GiB =
Gibibyte
TiB =
tebibyte
PiB =
Pebibyte
EiB =
Exbibyte
How many mebibytes in a gibibyte?
1024
How many gibibytes in a tebibyte?
1024
How many tebibytes in a pebibyte?
1024
How many pebibytes in an exbibyte?
1024
Order the data units from SMALLEST to largest
bit, nibble, byte, kibibyte, mebibyte, gibibyte, tebibyte, pebibyte, exbibyte
Order the data units from LARGEST to smallest
exbibyte, pebibyte, tebibyte, gibibyte, mebibyte, kibibyte, byte, nibble, bit
What’s missing from this list of data units - bit, ______, byte, kibibyte…
nibble
What’s missing from this list of data units - mebibyte, ______, tebibyte
gibibyte
What’s missing from this list of data units - gibibyte, ______, pebibyte
tebibyte
What’s missing from this list of data units - nibble, ______, kibibyte
byte
We use mebibyte, gibibyte etc, instead of megabyte, gigabyte because…
Mebibyte, gibibyte (etc) system of units is more accurate
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
What are sensors?
Input devices which read or measure physical properties from their surroundings
Examples of sensors
temperature, pressure, pH, humidity
Real data in nature is a________
analogue
What does analogue mean?
Constantly changing doesn’t have a single discrete value
Analogue data is converted to _______ format
digital
Analogue converted to digital using _______
ADC Analogue to digital converter
Sensors send out c______ values
constant
What analyses the input from sensors?
microprocessor
Temperature sensor
measures temperature of surroundings
Moisture sensors
measure water levels, e.g in soil
Humidity sensors
measure amount of water in the air
Light sensors
use photoelectric cells that produce output based on brightness of light
Infrared (active) sensors
uses invisible beam of infrared radiation with detector. If beam broken, then change has happened
infrared (passive) sensors
measure heat given off by an object
Pressure sensors
Transducer that generates electrical currents depending on pressure applied
Acoustic/sound sensors
Microphones that convert sound into electric signals/pulses
Gas sensors
measure gas being monitored, e.g. oxygen or carbon dioxide
pH sensors
measure acidity changes, e.g. in soil
Magnetic field sensors
Measure changes in magnetic fields
Accelerometer
Measure acceleration and motion of an application, e.g. change in velocity
Proximity sensor
Detect presence of nearby object
Flow (rate) sensor
Measure flow rate of moving liquid or gas and produce an output based on amount passing over sensor
Level sensor
Use ultrasonics (for liquid changes) or capacitance/conductivity (for static levels)
Example uses of temperature sensors
control heating system, control/monitor a chemical process, control/monitor temperature in a greenhouse
Example uses of moisture sensors
control/monitor moisture levels of soil in a greenhouse
Example uses of humidity sensors
measure humidity in a building, factory, greenhouse
Example uses of light sensors
switching on street lights on or off depending on light levels, switch on car headlights when it gets dark
Example uses of infrared sensors (active)
turn on car windscreen wipers when it detects rain, security alarm when intruder breaks beam
Example uses of infrared sensors (passive)
security alarm (detects body heat), monitor temperature inside a freezer
Example uses of pressure sensors
weighing of lorries at weighing station, measure gas pressure in a nuclear reactor
Example uses of acoustic/sound sensors
Security system - noise of footsteps, detect sounds of liquid dripping in a leak
Example uses of gas sensors
Monitor pollution levels at an airport, monitor oxygen and carbon dioxide levels in a greenhouse
Example uses of pH levels
Monitor/control acidity levels in the soil in a greenhouse, control acidity levels in a chemical process
Example uses of magnetic fields
detect magnetic field changes in mobile phones in smart phones, anti-lock braking systems in cars
Example uses of accelerometers
in cars for deploying airbags in a crash, used by phones to detect portrait/landscape
Example uses of proximity sensors
Detect when face is close to smart phone
Example uses of flow (rate) sensors
used in respiratory devices and inhalers in hospitals, measure gas flows in pipes
Examples of level sensors
monitor levels of petrol in gas tank, leak detection in refrigerant in AC units
How are sensors used in a monitoring process?
Sensors send signals to microprocessor, converted using ADC, checks against stored values, if outside value set, alarm sounds or message sent
How are sensors used in a control process?
Sensors send signals to microprocessor, converted using ADC, checks against stored values, if outside value set, signal sent to control values/motors etc, output checked against other sensors
Examples of monitoring sensors
monitoring of patient vitals in hospital, monitoring of intruders in security system, checking temperature levels in car engine, checking pollution in a river
Examples of control sensors
Turning on and off street lights at day/night, control temperature in heating/AC, control chemical process
What is virtual memory?
Type of memory created for temporary use and used as an extension of RAM
Where is virtual memory created?
In an area of the hard drive
Why is virtual memory needed?
Computers have a limited amount of RAM and need additional resources to run programs users need
What happens when RAM gets full and has more instructions to run?
It transfers some data to virtual memory until its needed
What’s data transferred from RAM to virtual memory (and back) called?
a page/pages
______ are moved to virtual memory when not needed then transferred back when processed
pages
What’s memory created for temporary use and used as an extension of RAM?
virtual memory
What’s created in an area of the hard drive to support RAM?
virtual memory
What are pages in memory?
data that’s transferred from RAM to virtual memory and back
What are the key parts in the virtual memory process?
RAM, pages, virtual memory and hard drive
What are benefits of virtual memory?
Programs larger than RAM can be processed. No need to waste RAM. No need to buy more RAM
What’s thrashing?
In virtual memory when swapping large amounts of pages, high rate of head movement reduces processing speed
What are privacy settings?
Controls available on web browsers, social networks and web sites desinged to limit access to personal profile
What controls available on web browsers, social networks and web sites desinged to limit access to personal profile?
Privacy settings
What kind of privacy settings are there?
Do not track, saving payment methods, safer browsing option, storing browser history/cookies, app settings like location data
What are these settings called? Do not track, saving payment methods, safer browsing option, storing browser history/cookies, app settings like location data
Privacy settings
What are proxy servers?
Proxy servers act as an intermediate between the user and web server
P______ s_______ act as an intermediate between the user and web server
Proxy servers
What are features of proxy servers?
Filter internet traffic, block access to websites, hide IP address, block requests from IP, prevents direct access to web server, helps prevent DoS & hacking
What do these features describe? Filter internet traffic, block access to websites, hide IP address, block requests from IP, prevents direct access to web server, helps prevent DoS & hacking
Proxy servers
A firewall can either be s_______ or h________
software or hardware
What is the purpose of a firewall?
Sits beween a users computer and external network - filters information in or out of a computer
Firewalls are the p________ d________ for computer systems to help protect it from hacking, malware, phishing and pharming
primary defence
Firewall main tasks are…
Examine traffic between users computer and a network, checks if incoming/outgoing data meets criteria, can block traffic that doesn’t meet criteria, logs all traffic
What’s main tasks are: Examine traffic between users computer and a network, checks if incoming/outgoing data meets criteria, can block traffic, log traffic?
Firewall
What is artificial intelligence?
The development of programs to simulate human behavior.
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
