1
Q
What is serial transmission?
A
Serial transmission is where data is transferred one bit at a time down a single wire
2
Q
What is parallel transmission?
A
Parallel transmission is where data is transmitted several bits at a time using multiple wires
3
Q
What is bandwidth?
A
Bandwidth is a measure of the capacity of the channel down which the data is being sent measured in hertz
4
Q
What is bit rate?
A
Bit rate is the rate of which data is actually being transmitted it is measured in bits per second
5
Q
What is latency?
A
Latency is the time delay that occurrs when transmitting data between devices
6
Q
What is asynchronous data transmission?
A
Data is tranmitted betweeen two devices that do not share a common clock signal
7
Q
What is a start bit?
A
A bit used to indicate the start of a unit of data transfer only asynchronous
8
Q
What is a stop bit?
A
A bit used to indicate the end of a unit of data transfer only asynchronous
9
Q
What is a parity bit?
A
A method of checking that binary codes have been sent correctly
10
Q
What is synchronous data transmission?
A
Data is transmitted where the pulse of the clock of sending and receiving device are in time. the devices may share a common clock.
11
Q
What does TCP/IP stand for?
A
Transmission Control Protocol/Internet Protocol
12
Q
What does HTTP stand for?
A
Hypertext Transfer Protocol
13
Q
What does FTP stand for?
A
File Transfer Protocol
14
Q
What does TCP/IP do?
A
It is two protocols that relate to the set of rules that govern the transmission of data around the Internet handles the routing and re assembly of these data packets
15
Q
What does HTTP do?
A
It is the set of rules governing the exchange of of different types of files that make up displayable web pages
16
Q
What does FTP do?
A
It is similar to http due to the fact they both provide rules for the transfer of files but ftp is commonly used when downloading program files or when you create a web page and upload to the ISP server
17
Q
What is a network?
A
Devices that are connected together to share data and resources
18
Q
What is a NIC
A
A card that enables devices to connect to a network it’s full name is a network interface card
19
Q
What does a NIC do?
A
A NIC is used in order to connect to a network. It is a printed circuit board inside the computer like any other card. It is mainly designed so that you can connect with another computer via a cable or wirelessly
20
Q
What are the the types of networks like the geographical area?
A
LAN and WAN and PAN
21
Q
What is network topology?
A
Is the layout of a network usually in terms of its conceptual layout rather then physical
22
Q
What is LAN?
A
LAN is a local area network. It is a network over a small geographical distance usually on one site and typically used by one organisation
23
Q
What is a WAN?
A
A WAN is a wide area network. Which is a network spread over a large geographical distance.
24
Q
What is star topology?
A
Star topology is a way of connecting devices in a network where each workstation has a dedicated cable to the central computer.
25
What is some advantages of star topology?
Fast connection as each client has their own cable
will not slow down as much when many users are connected
fault finding is easier as individual faults are easier to trace
relatively secure as each connection to the server is private
new clients can be added without affections the other clients
if one cable imor client fails then only that client is affected
26
What is some disadvantages of star topology?
Expensive to set up due to increased cabling costs
if the cable fails then that client may not be able to receive data
difficult to install as multiple canes are needed the problem is exaggerated where the LAN is split across a number of buildings
the server can get congested alas all communications must pass through it
27
What is bus topology?
A network layout that uses one main data cable as a backbone to transmit data
28
What are some advantages of bus topology?
Cheaper to install than a star topology as only one main cable is required
easier to install then a star topology
easier to add new clients by branch them off the main cable
29
What are some disadvantages of bus topology?
Less secure then star network as all data are transmitted down one main cable
transmission times get slower when more cables are used
if the main cable fails then all clients are affected
less reliable then star due to reliance on main cable
more difficult to find faults
30
What is physical topology?
The what in which devices in a network are physically connected
31
What is logical topology
The conceptual way in data is transmitted around a network
32
What is a client server network
A network methodology where one computer has the main processesing power and the storage and the other computers act as clients requesting services from the server
33
What are some services that a client server network could offer?
Access to a printer
providing a secure connection to the internet
access to email
access to applications
access to files
34
What is. A peer to peer network?
A network methodology where all devices in a network share resources between them rather than having a server and thus no one computer is in control
35
What is a WWAN?
It is a wireless wide area network. It is a WAN that does not use cables but sends data using radio waves
36
What is a WLAN?
It is a wireless local area network. It is a LAN that does not use cables but connected using radio waves.
37
What is a MAC address?
It is a unique code that identifies a particular device on a network
38
What is WiFi
WiFi is a standard method for connecting devices wirelessly to a network and to the Internet
39
What is a SSID?
A locally unique 32 character code that identifies a device on a wireless network
40
What is RTS/CTS
A protocol to ensure that data does not collide when being transmitted on wireless networks
41
What is WiFi protected access?
WPA/WPA2 is a protocol used for encrypting data and ensuring security on WiFi networks
42
What is a domain name?
It is the recognisable name of a domain on the internet
43
What is a URL?
A URL is a uniform resource locator it is a method for identifying the location of resources like websites on the internet
44
What is a DNS?
A DNS is a server that contains domain names and am associated IP addresses
45
What is a port?
A port is used to identify a particular process or application on a network
46
What is POP 3
A protocol for receiving emails
47
What is a DNS system?
A system of connected domain servers that provide the IP address.if every website on the internet
48
What is port forwarding
A method of routing data through additional ports
49
What is a socket
An endpoint of a communication flow across a computer network
50
What is subnet masking
It is a method of dividing a network into multiple smaller networks. It splits it into a network identifier and a host identifier
51
What is a gateway?
This is used whilst using subnet masking. It is a node on a network that’s acts as a connection point to another network with different protocols
52
What are internet registries?
They are an organisation who allocate and administer domain names and IP address
53
What is the RIR
It is the regional internet registry. It is one of the five large organisations that allocate and administer domain names and IP address in different parts of the world
54
What is a packet?
A block of data being transmitted
55
What is routing?
It is the process of directing packets of data between networks
56
What is packet switching
A method for transmitting packets of data via the quickest route on a network.
57
What is a checksum
A method of checking the integraty of data by calculating a sum based on the data being sent
58
What is IP V6
It is an upgrade to IPV4 where each thing on the internet is assigned a unique ip address. It uses 128 bits in eight groups of four hex numbers
59
How is a packet made up?
Header 200 bytes
contains:
MAC address of sender and receiver
The sender and receiver ip
Which protocol is being used
Packet number or sequence number
Body 822 bytes
Contains
The actual data
Footer 2 bytes
Contains
A checksum
60
What is packet filtering?
A trchnique used to examine the contents of packsets on a network and rejecting them if they do not conform to certain rules
61
What is stateful inspection?
A more advanced technique used to exam in the contents of packages on a network and rejecting them if they do not from part of a recognised communication
62
What is symmetric encryption
Where both the sender and receiver both use the same key to encrypt and decrypt the data
63
What is asymmetric encryption
This type of encryption is where you encrypt a piece of data using someone’s public key so only they can decrypt it with their own private key as the two keys are mathematically related
64
What is a digital certificate?
A method of ensuring that an encrypted message is from a trusted source as they have a certificate from a certification authority
65
What is a certification authority?
A trusted organisation that provides certificates and signatures
66
What is a digital signature?
A method of ensuring that an encrypted message is from a trusted source as they have an unique encryption signature that is verified
67
What is a Trojan?
Malware that is hidden within another file on your computer it is often designed as another piece of software that you would want to download or as data like a video game
68
What is the generic term for malware?
A virus - malware where the program attaches itself to another file in order to infect a computer
69
What is a worm?
A worm is a type of malware that replicates itself and spreads around a computer system. It does not need to be attached to another file in order to infect a computer
70
what are some common ways to protect against trojans viruses and worms?
Use antivirus software
ensure sites use https
encypt data files
Select a program language with built in security features
Keep code up to date
71
What is the layers of the tcp/ip protocol
Application
transport
network
link
72
What is the application layer?
Purpose: Handles protocols like HTTP, HTTPS, FTP, SMTP, etc.
Key Role: Converts data formats for communication (e.g., sound, video), encrypts/decrypts, ensures compatibility across devices.
Example: Receiving an email via SMTP or accessing a website via HTTPS.
73
What is the transport layer?
Purpose: Manages end-to-end communication between devices.
Key Role: Ensures complete data transfer, error checking, and connection setup/termination.
Example: Uses port numbers to send data to the right app on a device.
74
What does the network layer do
Assigns IP addresses
• Routes data packets between devices
75
What does the link layer do
• Handles physical transmission (0s and 1s)
• Manages data flow and network topology
• Controls signal strength and wireless protocols like CSMA/CA
76
What does https and http do?
HTTP (Hypertext Transfer Protocol)
• Governs how multimedia (text, images, video) is transmitted across the web.
• Uses the client-server model (browser requests; server responds).
• Not secure by default.
HTTPS (Secure HTTP)
• Adds encryption via SSL/TLS for secure transmission (e.g., banking, login).
• Ensures data privacy and integrity.
77
What does FTP do?
Purpose: Transfers files over the Internet.
Common Uses:
• Uploading web content
• Downloading software
Features:
• Can be anonymous or password-protected
• Less used for viewing content, more for program/data transfer
• Uses TCP/IP layers
78
What does SSH do?
Purpose: Secure remote access to computers (e.g., IT support).
Key Features:
• Encrypts data (uses public key encryption)
• Uses command-line interface (e.g., cd, rm, mv, cp, vi)
• Enables access to folders, programs, and resources remotely
• Uses the client-server model
79
What does SMPT and POP3 do
Flashcard 4: SMTP & POP3 (Email Protocols)
SMTP (Simple Mail Transfer Protocol)
• Sends emails
• Uses ports 25 and 587
• Works through mail servers with DNS to find recipients
POP3 (Post Office Protocol 3)
• Receives emails
• Uses port 110
• Downloads and stores messages locally (e.g., MS Outlook)
80
What do email services and web servers do?
Email Server:
• Stores and manages incoming/outgoing emails
• Accessible via clients like Outlook
Web Server:
• Hosts web content
• Uses protocols like HTTP/HTTPS
• Delivers multimedia (text, images, video) to browsers
• Must be fast and reliable, especially for businesses
81
What do web servers and DNS do?
Web Browser:
• App to view and interact with web pages
• Loads content via protocols like HTTP
• Examples: Chrome, Firefox, Edge
DNS (Domain Name System):
• Translates URLs (like www.example.com) into IP addresses
• Allows the browser to locate and load the correct server
82
What is the client–server model?
A methodology for connecting computers over a network where one computer (server) provides resources and services to other computers (clients).
83
What is a star topology?
A network setup where each client has its own physical cable connection to a central server.
84
What is the role of the client in a client–server model?
The client has few resources and requests services from the server.
85
Give examples of server types in a client–server model.
File server, Web server, Proxy server, Print server, Database server, Application server
86
What is the basic communication principle in a client–server model?
The client makes a request; the server responds and provides the requested service.
87
What is an Application Program Interface (API)?
A set of subroutines that enable one program to interface with another.
88
What is the websocket protocol?
A protocol that creates a persistent, full-duplex connection between client and server for bi-directional messaging.
89
What are CRUD operations?
C: Create, R: Retrieve, U: Update, D: Delete
90
Match CRUD operations with SQL commands.
Create → INSERT, Retrieve → SELECT, Update → UPDATE, Delete → DELETE
91
Match CRUD operations with HTTP methods.
Create → POST, Retrieve → GET, Update → PUT, Delete → DELETE
92
What is REST?
Representational State Transfer – a methodology for implementing networked database applications using HTTP.
93
What is the process in the REST model?
1. Client sends request via browser. 2. Web server passes it to an API. 3. API queries database server. 4. Data is returned in JSON or XML.
94
What are HTML files used for in REST?
To ensure data is displayed in the correct format on the client side.
95
What data formats are used to return results in REST?
JSON (JavaScript Object Notation) or XML (Extensible Markup Language).
96
What is JSON?
A human-readable, compact data format made of objects and values, easy for both humans and computers to understand.
97
What is XML?
A markup language that defines how data is encoded; similar to writing code in a programming language.
98
What is a thin client?
A network where one computer contains the majority of recourses processing power and storage capacity which it distributes to other clients
99
What’s a thick client
A network where resources processing power and storage capacity are distributed between the server and the client computer
100
What’s a terminal
A computer that has little or no o processing power or storage capacity used as a client in a thin client network
101
What are some advantages and disadvantages of the thin client model?
+
Easy and cheaper to set up new clients as fewer resources are needed
easier for the network manger to control clients
Greater security as clients have fewer access rights
—
High spec servers are expensive
can slow down with heavy use
Clients are dependent on server so if it goes down all clients are affected
102
What are some advantages and disadvantages of the thick client model
+
Reduced pressure on the server leading to more uptime
Client can store programs and data locally giveing them more control
Fewer servers and lower bandwidth needs
Suitable for most devices including phones and tablets
—
reduced security if clients can download software
More difficult to manage and update as new hardware and software need installing
Data is more likely to be lost or deleted on the client machine
Can be difficult to ensure data integrity where many clients are working on local data
Computer Science A Level
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