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Paper 2 Flashcards

1
Q

What is natural numbers and its symbol?

A

All positive numbers whole numbers (integers) including zero

Symbol: N

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2
Q

What is integer numbers and its symbol?

A

All whole numbers including negatives and zero

Symbol: Z

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3
Q

What is rational numbers and its symbol?

A

Numbers that can be expressed as fractions

Symbol: Q

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4
Q

What is irrational numbers?

A

Numbers that cannot be expressed as a fraction

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5
Q

What is real numbers and its symbol?

A

Any number that isn’t infinity or imaginary

Symbol: R

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6
Q

What is ordinal numbers?

A

Numbers that can describe the position of an object

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7
Q

Why is hexadecimal used?

A
  • Easy to represent a byte with two digits

- Easier for humans to remember

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8
Q

What is Unsigned and signed binary?

A

Signed binary - Binary values that can store both positive and negative values

(We use two’s compliment to represent this)

Unsigned binary - Binary values that can only store positive values

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9
Q

What are the advantages and disadvantages of fixed point(Signed Binary) and floating point(2s Complement) forms in terms of range, precision and speed of calculation?

A

Fixed point
+Allows for much faster processing compared to floating point numbers as no processing is required to move the binary point
+The absolute error will always remain the same, unlike floating point numbers

Floating point
+Wider range of numbers can be produced with the same number of bits as the floating point system
+

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10
Q

Why is floating point numbers normalised?

A

Allows the maximum possible precision with a given number of bits

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11
Q

Explain underflow and overflow and describe the circumstances in which they occur.

A

Overflow - When the number is too large for the number of bits allocated

Underflow - When the number is too small for the number of bits allocated

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12
Q

How does bit patterns represent sound?

A

This can be done by measuring and recording the amplitude of the sound wave, using a microphone, at given intervals. The more frequent the samples are taken, the more accurate the sound will be presented.

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13
Q

What’s the difference between analogue and digital?

Involving data and signals

A

Analogue data - Data that is infinitely variable and are often represented in the form of a wave

Digital data - Represented as discrete values

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14
Q

Describe the principles of an analogue to digital converter (ADC)

A

A microphone converts the sound energy to electrical energy. Regular samples are taken of the analogue signal at a given frequency, measuring the amplitude of the wave at each point and converting it into binary value according to the resolution or bit depth.

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15
Q

Explain how bitmaps are represented.*

A

An image made up of individual pixels, arranged as a grid

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16
Q

What is resolution for images?**

A

The number of pixels per inch

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17
Q

What is colour depth?

A

The number of bits needed to stored each pixel

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18
Q

Advantages of normalised floating point format over fixed point format?

A
  • To allow a wider range of values to be stored
  • To minimise rounding errors
  • Greater accuracy
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19
Q

What is metadata and what data might it contain?

A

Extra information about an image.

  • Dimensions (h*w/ radius ect)
  • Colour depth
  • file type
  • Gps coordinates
  • Time and date of photo taken
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20
Q

What is the formula for pixel resolution?

A

resolution = height (in pixels) * width (in pixels)

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21
Q

What is Nyquist theorem?

A

In order to produce an accurate recording, the sampling rate must be at least doubled that of the highest frequency in the original signal.

The average human can hear frequencies up to 20,000Hz

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22
Q

What is MIDI and a event messages and how is it represented?

A

A protocol that allows electronic instruments and other digital musical tools to communicate with each other.
Event messages specifies the pitch and duration of a note

MIDI represents sound as sequence of event messages // MIDI stores properties of the
notes played;

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23
Q

Advantages of using MIDI files for representing music over digital audio formats?

A

-MIDI files tend to be much smaller, therefore requiring less memory which leads to faster load times
-Completely editable
-Can support a wide range of instruments
Can produce very high quality reproduction of the instruments

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24
Q

What is the formula for the file size of sound?

A

Sample rate x Resolution x seconds

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25
What is the formula for the file size of a bitmap image?
Number of pixels * colour depth
26
How to calculate the range of a given number of bits of 2^8? | find the biggest number and range of values you can have
``` 2^8 = 256 values as you can also represent 0 2^8 = 255 is the biggest number that you can represent ```
27
Describe the principles of an digital to analogue converter (DAC)
- convert binary into electrical energy - that then vibrates the speaker - that creates pressure waves which are the analogue sound
28
What is sampling rate?
Represents the number of samples that will be taken per second
29
What is sample resolution?
The number of bits allocated to representing the sound
30
Explain why both fixed point and floating point representation of decimal numbers may be inaccurate?
They both have rounding errors
31
What base is decimal, binary and hexadecimal?
Decimal - 10 Binary - 2 Hexadecimal - 16
32
Describe sampled sound:
- Sampled sound records measurements of the amplitude of a wave - Samples are taken at regular intervals - Each sample is stored in a fixed amount of memory
33
How is sampled sound represented?
Sampled sound records measurements of (the amplitude) of a wave; Samples are taken at regular intervals; Each sample is stored in a fixed amount of memory; A. each sample is the same size
34
What are the two types of classification software?
System Software, Application Software
35
What are the 4 types of System software?
Operating System, Utility Programs, Library Programs, Programming Translators
36
What are the 3 types of Application Software?
Bespoke Software- made for a custom tasks Generic off the shelf software-Designed to complete a broad range of tasks Special Purpose (ready made)-Made for one particular task
37
What are operating systems and what is the function of it?
A program that designed to hide the complexities of hardware from the user. Manages the operations of the computer for the user, acts as a bridge between the user and computers hardware. Eg. Windows, MacOS, iOS Function - Moving data into and out of Ram - Allocate I/O devices to processes - Decides which process to carry out - Disk fragmentation Allocate processors/cores to processes // schedule processes // decide which process to carry out when; Allocate memory/RAM to processes // moving data into and out of RAM / to a paging file for virtual memory // ensuring processes can only write to memory that they have been allocated; Allocate I/O devices to processes // manages communication between processes and I/O devices // automatic installation of drivers for new I/O devices; A. examples of devices NE. manages I/O devices Allocate space on a storage device to files // organising files into directories // determines where on a device to save a file // recognising storage devices when they are connected; A. defragmentation of disks NE. saving a file Installation of new software // automatic/managing updating of software; A. “programs” or “tasks” for “processes” R. handling interrupts R. hides complexity Note: Students must describe the type of resource management – phrases such as “processor management”, “allocating memory” etc are not enough.
38
Define Software and Hardware?
Hardware is all the physical components that make up a computer Software is the programs that run on a computer
39
What are Utility programs and examples of it?
Small programs with one specific purpose that is designed to optimise the performance of the computer. - Disk Defragmenter - Virus Checker - Backing up files - compressing or decompressing data - encrypting data - providing a firewall
40
What are library programs and examples of it?
Ready compiled programs which can be run when needed. -Maths calculations
41
What are programming translators and examples of it?
Converts program code by a programmer into machine code which can be run by the computer -Compilers, Interpreter, Assembly
42
What is System Software?
- Software that is needed to run the computers hardware and application programs - Software that performs tasks to run computer; - Layer of software which enables user to operate computer; - Software that hides complexity of computer from user/provides virtual machine; - Software that lets user communicate with/manage hardware; - Software to run applications/hardware/programs/computer/ packages; - Software required to make computer work;-
43
What is Application Software?
Software that carries out tasks that the user is interested in doing such as writing a letter, creating graphs, sending an email or downloading a webpage. Performs tasks for the user
44
How does a operating system manages memory management?
It manages how much RAM a program has access to which allows multiple applications to run simultaneously.
45
How does a operating system manages processor scheduling?
Involves deciding what order to execute each instruction in. Only executes one instruction at a time
46
How does a operating system manages peripherals?
The OS uses device drivers to communicate with I/O devices connected to the computer system.
47
What is 1st generation language and its level?
(Low Level) | Machine Code - A line of code (1's & 0's) split into opcode and operand
48
What is 2nd generation language and its level?
(Low Level) | Assembly Language - The opcode is mnemonics and the operand is decimal/ hexadecimal
49
What is 3rd and 4th generation language and its level?
(Both High Level) High level language - E.g. C#, Java etc Declarative Language - You state what you want, not how to do it
50
What are the advantages and disadvantages of high level languages compared to a low level language?
+Relatively easy to learn +Easier and quicker to write in high level language +Capable of running on multiple different computers -Requires a compiler to run
51
What are the 3 different types of programming translators?
Compiler, Interpreter, Assembler
52
What is the difference between a compiler and an interpreter?
- A compiler produces object code whilst an interpreter does not - A compiler translates the whole of the source code into object code whilst an interpreter translates line by line -The object code produced by a compiler will execute faster, (once it is compiled) than interpreting the source code (every time the program is run) -An interpreter can run (syntactically correct) parts of a program whilst there are syntax errors in other parts of it, which a compiler cannot;
53
What is inputted into a compiler and assembler and outputted?
Source code goes in; object code comes out
54
What is an assembler? i.e. what does it do?
It converts low level language into the correct machine code
55
List advantages of a compiler over interpreters?
- Object code executes faster than interpreted code | - Object code is more secure as it cannot be read
56
Compiler and interpreter. Describe situations in which each would be appropriate.
``` Compiler -Games/ Movies - Interpreter -To debug code - ```
57
What is a edge triggered D type flip flop and what is it used for?
A flip flop is an elemental sequential logic circuit that can store one bit and flip between two states, 0 and 1. Used for creating registers and counters
58
What is the data protection act?
Specifies the rules on collecting and holding data - Data must be accurate & up to date - Data must be protected - User has the right to see the data thats being hold
59
What is the computer misuse act?
Designed to prosecute hackers who gain unauthorised access
60
What is ethics?
Decisions based on an individual
61
What is morals?
Widely shared decisions about right and wrong
62
What are machines good and bad at?
Good at: - Machines are accurate - Consistent - Doesn't require breaks Bad at: - Shape detection - Processing qualitative data - Poor with unexpected circumstances
63
What is the copyright, design & patents act?
Protects an owners creative work from being illegally copied
64
What is the regulation of investigatory power act?
Gives certain bodies the right to monitor communications and internet activity
65
What is the freedom of information act?
Provides the public access to information held by public authorities
66
What is the health & safety regulations?
This helps keep users using computing equipment safe ie the positioning of the chair monitor ect
67
What is personal data?
Data that can identify a specific living person
68
What does OCR stand for and what does it mean?
Optical Character Recognition Technology used to distinguish printed or handwritten text within digital images
69
What is DRM and what does it stand for?
Digital Rights Management A way for protecting digital content
70
What are the advantages and disadvantages of digital rights management?
+Protects copyright +Ensures creators receive payment for their work - Relies on the company to exist - Prevent uses on multiple devices
71
What is a hacker?
Someone who try's to gain unauthorised access to a computer system
72

What is serial transmission?

Serial - Single bits are sent along a single wire one after the other at a time

73

What is synchronous data transmission with an example?

When data is transferred at a regular intervals synchronised by a clock pulse

E.g Chats and video

74

What is asynchronous data transmission with an example?

When data is sent separately and as soon as they are ready

E.g keyboard and mouse

75

What is the purpose of start and stop bits in asynchronous transmissions?

They are a bit used to indicate the start and the end of a set of data in asynchronous data transmission

76

What is baud rate?

The number of times a signal in a communication changes state per second

77

What is bit rate?

The number of bits transferred between devices per second

78

What is bandwidth?

A measure of maximum capacity of a given transmission channel

79

What is latency?

The time delay between when a transmission data is first sent to when its delivered at its destination

80

What is a protocol?

A set of rules that govern communication between devices

81

What's the relationship between bit rate and bandwidth?

The relationship between bandwidth and bit rate is directly proportional: the greater the amount of data that can be transmitted over a channel, the more bits can be transmitted per second.

82

What is peer to peer networking and when they might be used?

No central server. All clients have equal responsibility so each computer can act as both a client or a server

E.g small businesses, home networks

83

What is client server networking and when they might be used?

When a device (client) requests access to resources and services from a central server

Eg schools - students as clients

84

What are the advantages and disadvantages of peer to peer networking?

+If a node goes down only the data on that node is lost
+Easily share files

-Less secure
-

85

What are the advantages and disadvantages of a client-server networking?

+Increased security
+Backups can be done for all clients
+Data can be shared

-Expensive to install and manage
-Professional IT staff are required to maintain the servers

86

What is the purpose of Wi-Fi?

Allows you to transfer data between devices without cables components being required for a wireless network

87

What components are required for wireless networking?

Each device must have a wireless network interface card (NIC) to be able to connect to a wireless access point (WAP). The WAP allows devices to connect to a wired network (internet)

88

What is the difference between thin and thick clients?

Thin clients - Majority of the processing and storage is done on the server
Thick clients - Majority of the processing and storage is done on the client

89

What is the transmission control protocol/ internet protocol (TCP/ IP) and the 4 layers?

It's 4 layers required to allow data to be transmitted across the internet

Application, Transport, Network, Link

90

What is the application layer in the TCP/ IP?

Selects the appropriate protocol for communication

E.g FTP, HTTP/S, POP3

91

What is the transport layer in the TCP/ IP?

Creates an end to end connection and splits the data into packets and numbers them

92

What is the network layer in the TCP/ IP?

Adds the source and destination IP address and routers use the IPs to route the packets to the destination

93

What is the link layer in the TCP/ IP?

The physical connection between the nodes and adds the source and destination MAC addresses

94

What are MAC addresses and where is it used in the TCP/IP?

A unique code that's physically hardcoded on every NIC during manufacturing.

Used in the link layer of the TCP/IP

95

What is parallel transmission?

Parallel - Single bits are sent along several wires simultaneously

96

What are the advantages and disadvantages of thin clients?

+Software updates can be done once on a server and automatically end up on every client
+Easy to set up and maintain e.g. adding a new terminal to the network
+Much more secure as all data is stored in one place

-Very reliant on the central server
-Can be expensive as it requires a powerful and reliable central server
-High demand on bandwidth

97

What are the advantages and disadvantages of thick clients?

+Reliable
+Can operate without a continuous connection to the server
+Preferred when running heavy duty software

-Expensive as each client may need a higher specification (better computer)
-Time consuming when installing new software

98

What are the advantages and disadvantages of serial transmission?

+Reliable over long distance
+Reduced cost as less wires are required
+Reduced chance of skew

-Slower than parallel transmission
-

99

What are the advantages and disadvantages of parallel transmission?

+Ideal for short distances
+

-Close wires can cause a corruption
-Prone to skew (Timing issues)

100

Synchronous V Asynchronous

-Asynchronous is slower due to the extra bits and gaps
-Asynchronous can transmit when ready as it doesn't need to wait on a clock pulse

-Synchronous may have to wait for a clock pulse before it can be sent
-Synchronous requires a synchronised clock between devices which can be difficult

101

What layer in the TCP/ IP stack does the router operate?

Network

102

What is a router and where and why is it used?**

A device that connects two or more devices together and forwards data packets between networks

Used for:
Internet access

Where:
Homes
Offices

103

What is a gateway and where and why is it used?

A node that sits between different networks and converts data from one protocol to another

Used to:
Connect two different company networks together
Provide a house user access to the internet

104

What are the main components of a data packet and what does each part contain?

Header - Source and destination IP and Mac address, Packet and sequence number

Payload - The actual data itself

Trailer - A checksum to ensure that the data has been received correctly

105

What is the role of packet switching?

A method of sending data across a network to reach a destination

106

What is a uniform resource locator (URL)?

A method of identifying the location of resources on the internet

107

What is a fully qualified domain name (FQDN)?

The complete domain name that identifies a specific host on the internet. It includes the host server name along with the domain name

 

Eg www.stephanbarnes.com

108

What is a domain name?

Identifies the location of the the resource on the internet.

Identifies organisations or groups on the internet

109

What is an IP address?

A unique address that is assigned to a network device

110

How are domain names organised?

They are organised in a hierarchy 

111

What is a node?

Any system or device connected to a network

112

What is the purpose of a Domain Name System (DNS)?

To link a fully qualifies domain name (FQDN) to an IP address

113

What are the 5 components of a URL?

Https://stephanbarnes.com/alevel/computing/flashcards

Host, FQDN, Domain Name, Location, Resource

114

What is the formula for bitrate?

Baud Rate * Number of Bits per Baud

115
Describe one situation when a DNS query will not be sent to a remote DNS server.
The local computer already has a copy of the IP address in a host file.
116
What is normalisation?
The process of ensuring that a database is designed in its most efficient form
117
What is 1st Normal form?
Doesn't contain repeating attributes and all values cant be broken into separate parts
118
What is 2nd Normal form?
Same as 1st but contains no partial key dependency
119
What is 3rd Normal form?
Same as 2nd Normal form but it contains no non key dependency
120
What is a database?
A collection of data in an organised and logical way
121
What are the 4 types of relationships in relational databases?
One to One One to Many Many to One Many to Many
122
What is a relational database?
A collection of tables in which relationships are modelled by shared attributes
123
What is are attributes?
Describing characteristics of an object in a database
124
What is a primary key?
An attribute that can uniquely identify a row
125
What is a composite primary key?
An attribute that can be used to uniquely identify every record within a table
126
What is a foreign key?
An attribute in a table that is a primary key in another table and is used to link tables
127
Why are databases normalised?
To allow the database to be as efficient as possible by reducing the amount of redundancies (repeated data)
128
What is SQL?
A text based querying system. Used by a lot of relational databases
129
What are the two parts of SQL and what are they?
DDL - Used to create database tables DML - Used to retrieve, Update, Insert and delete data in a database
130
What is an entity?
An object (person/event) that data is stored for
131
What is 0NF?
A table with no normalisation, all data and fields in one table.
132
What is the concept of a relational database?
A method of creating a database using tables of related data, with relationships between the tables
133
What is the full name given for the Copyright law.
Copyright, Design and Patient Act
134
What’s the difference between direct addressing and immediate assessing?
Direct addressing means that the operand is the (memory) address whereas immediate addressing means the operand is the value

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