Internet Flashcards
Operating System definition
a collection of programs that control the operation of the computer application programs and any attached devices. Runs all the time in background when computer is on
Functions of an OS
- Managing how data is recieved from input devices and sent to output devices
- Controlling where programs and data are located in computer’s memory
- Providing user interface between user and computer so they can interact with it
- Managing file systems
- Controlling access and security
Layer model of a computer
illiustrates role of operating system
1. User
2. Application Program
3. OS
4. Hardware
Each communicates to the next
World Wide Web definition
system of connected files hosted on the internet. Connected using hyperlinks. Includes web pages, pictures, video, sound and other file formats that can be searched and browsed.
Internet of Things
network of internet-enabled devices, excluding traditional computers like laptops and servers. These devices can connect via Wi-Fi, Bluetooth, or near-field communication (NFC).
Application Programs
Carry out specific tasks or related tasks.
They communicate with the operating system which in turn controls how the application interacts with hardware
Internet
Global network of computers all connected together
Internet vs WWW
Internet is whole network of computers no matter what protocols computers use. World Wide Web is files hosted on the internet connected using hyperlinks via HTTP and HTTPS protocols
Client-server model
Web client sends a browser request to a web server. This browser request is then processed by the web server which responds by sending the result back to the client in the form of a server response. It is a simple distributed system
Simple distributed system
system where the workloads required to complete a task are shared between more than one computer. Computers are connected by a network in order to communicate and complete the task.
Client Server Model security advantages
- Unified management of security and makes it simple to enact regulations and safety measures
- Access Control ensures only people with permission can access data
- Logging. Servers can preserve a thorough record of user behaviour which can be used to track behaviour if there is a security concern.
Protocol
A communication protocol is a set of rules describing how to transmit data across a network, ensuring computers communicate effectively.
What does HTTP stand for and HTTPS
Hypertext Transfer Protocol
Hypertext Transfer Protocol Secure
What does IP stand for
Internet Protocol
What does TCP stand for
Transmission Control Protocol
Protocol Layers and how requests travel
the separate functions within the overall task of transmitting data between processes
1. Application
2. Transport
3. Network
4. Data link
Travels down the client, through the internet and then up the server. Request sent back through same path.
Application Layer
Encodes/Decodes the message into a form understood by sender and recipient devices using protocols like HTTP, FTP and SMTP
Transport Layer / TCP function
TCP Breaks down message into small pieces called packets and keeps track of them. Establishes a connection before data transfer and performs error check. Each packet is given a packet number and the total number of packets. Recipient uses this information to assemble packets in correct order, also allows to see if any are missing.
Network Layer / IP function
(AKA Internet Layer) Adds sender’s and recipient’s IP address. Every computer connected to the internet has unique IP address and IP ensures that every packet has correct IP adresses. Network then knows where to send message and where it came from.
Data link Layer
Enables physical transfer of packets between nodes on a network, and between one network and another
HTTP vs HTTPS
HTTPS is secure, HTTP isn’t
HTTPS sends data over port 443, HTTP uses port 80
HTTPS operates at Transport Layer, HTTP operates at Application Layer
SSL certificate signed by CA required for HTTPS
TCP/IP
TCP and IP are often combined into one family the TCP/IP protocol stack. Forms the basis for communication on the Internet.
IP address
unique identifier for all devices connected to the internet, helping them to communicate.
Helps to figure out where online activities are coming from and going to.
IPv6
latest version of the internet protocol which has a lot more addresses than IPv4
VOIP
Voice Over Internet Protocol. Not a single protocol but a number of methods, designed to deliver voice data and associated data(often video) over the Internet. E.g. Zoom, WhatsApp all use VOIP
WiFi
Radio wave technology that allows devices to communicate with each other and access the Internet wirelessly. Wifi protocol operates at Data link Layer and manages flow of data around a wifi network
Gateways
Connect two networks that have different protocols
Routers
Forward data packets between computer networks
Network Bridges
Creates a single network from multiple network network segments
Network switches
Forward data only to devices that need to recieve it
Repeaters
Recieve data and re-transmit it. Often used in fibre optic cables to boost signal strength
Cloud Computing
storing, processing and accessing data, programs or services over the internet on servers that are specifically designed for these purposes.
Benefits of cloud computing
Ability to share files easily between many users
Remote access to files
Always having access to the most up-to-date software
Cloud Computing Problems
Security Breach Risk
Requirement of internet connection to access
