Computer Science - Unit 3

ARPANET

ARPANET

First network that connected 4 computers from 4 colleges

The Internet

A global network of billions of computers and other electronic devices

Internet Service Provider

Gives access to the global network

Dial up

Slowest type of internet connection; uses phone line to connect to internet

Cable

Connects to internet via cable TV, must be available to work; uses broadband connection;

Satellite

Uses broadband, connects to internet though satellites orbiting Earth; can be affected by weather patterns

3g, 4g, 5g

Connects wirelessly through ISP’s network

Protocals

Rules to govern how computing devices that connect to the internet ‘talk’ to each other

Computing Device

Physical artifact that can run program

Computing System

Group of computing devices and programs working together for a common purpose

Computing Network

Group of interconnected computing devices capable of sending or receiving data; type of computing system

End-to-end connectivity

Principle that anyone can connect to the internet and communicate with anyone else on another ‘end’ at any time

Trade off

Balancing act of making decisions between different factors when creating a maintaining a network

Centralized network

Concentrate resources and control in one location; may create a single point of falure

Distributed network

Distributes resources and control across multiple locations; potentially increases complexity

Bandwidth

The number of bits we can send in a fixed amount of time

Mbps

Megabits per second; used to measure bandwidth

1 Mega-bit

1,000,000 bits

Latency

How long it takes data to travel between its source and destination

Satellite Internet Connection

High latency, high bandwidth

Dial-up Internet Connection

Low latency, low bandwidth

Cable Internet Connection

Low latency, high bandwidth

Copper Cables

Transmits data using electrical signals over copper wires

Optical Fibers

Transmit data using thin strands of lass or plastic as pulses of light

Wireless Connections

Transmit data between devices, wireless routers, and cell towers as radio waves

Packets

Pieces of binary information that are formed from digital data

Packets contain

The binary code for the data, the ip address of where it came from, and the ip address of where it is going

Router

Type of computer that forwards data across a network path towards the IP address of intended receiver

Redundant paths

If one path is busy, additional paths with be available

Transmission control protocol (TCP)

Breaks down and reassembles information you wish to send into packets

Scalable internet

Being able to add more networks, routers, and infrastructures without having to rewire the internet

Rework redundancy

The Internet has multiple backups to ensure reliability during cases of high usage failure

Fault tolerance

The internet had the ability to handle issues that arrive in the network

Open protocols

Allows users to easily connect additional computing devices to the internet

TCP/IP

Main building blocks of the internet; help computers find each other and send data correctly

HTTP

Protocol for web pages; how computer asks web server to send a webpage so its visible in the browser

SMTP

Protocol for sending emails; makes sure they get to correct email server

IP address

unique number given to every device when it connects to internet

IP

The protocol for web addressing

Domain Name System (DNS)

Helps computers find a website when its name is types into web browser

HTTP

Protocol that makes World Wide Web work; set of rules that computers use to communicate with each other

HTML

Language of webpages; tells computer how to display a web page

SSL/TLS

Layer of security wrapped around communications

CA

A trusted entity when it comes to distributing and verifying the identities of websites

HTTPS

Ensures HTTP requests are secure and protected

Cookies

Pieces of information that websites store on a computer to revisit

WWW

A system of linked pages, programs, and files

URL (Uniform Resource Locator)

The web address; how you find and access things on the internet

Internet of thing (IOT)

A network of interconnected and communicating objects we use every day

Artificial Intelligence (AI)

Machines that are programmed to mimic human intelligence and learn to make autonomous decisions

Blockchain

A digital record-keeper for financial transactions or data transfers

The IoT is made up of

A network of physical objets that are embedded with sensors, software, and connectivity capabilities

AI involves

The creation of algorithms and models that allow machines to process and interpret data in ways that mimic human cognitive functions

Blockchain creates a secure and unchangeable record of

Transactions or data online

Is the Blockchain a centralized or distributed network?

Distributed network

Data processing

The manipulation and transformation of raw data into meaningful information

Primary Storage

Temporary storage where data is held for immediate processing by computers CPU; volatile

Volatile

Data storage that is lost when the computer is powered off

Secondary Storage

Storage where data is stored for long term; non-volatile

Non-volatile

Data sotrage that is preserved when the computer is powered off

Sequential Computing

Processes data one instruction at a time

Distributed Computing

Processes data by distributing tasks across multiple networks or servers

Distributed Computing uses

More than one computer

Peer-to-Peer Network

Distributes tasks involved in data processing across individual devices

Parallel Computing

Processing data by having multiple processors working together on a task simultaneously

Cloud Computing

Delivers computing services over the internet

Digital Divide

The gab between individuals who have access to digital technologies and those who do not.