CSP Unit 1 & 2

https://docs.google.com/presentation/d/1yBfIXY_FdWce8PH093xQ5QQTQi0seWLMzC9v-fLYxtc/edit#slide=id.g289419ba35a_0_122 https://docs.google.com/presentation/d/1-XBXRXOMpU1-RBFYugnJsfrnrxzCvxTLlJr5iKrM4uQ/edit#slide=id.p

How do computers store data?

Binary numbers

How many bits are in a byte?

8 Bits

If you have an 8-digit binary number, what is the maximum possible value?

255

Lossy compression

• Compresses more data than lossless compression

• Permanently discards some unneccasry data from the information

• Used in JPEG images, MP3 audio files, and some streaming platforms in which case a small loss of quality is considered okay

Lossless compression

• Reversible form of compression (reconstructed after)

• Identifying and removing redundant data, and combining repetitive data, but not getting rid of anything important

• Used in PNGs, GIFs, text documents, etc

Analog Data

Real world data

For example: listening to a live music performance

Digital Data

Computer data

For example: listening to a music performance on Spotify

How are colors stored in a computer?

3-byte binary numbers with one byte per color

Red:Green:Blue ← in that order

Increasing bits in a number

Adding one digit DOUBLES the amount of representable values. Add n digits increases the amount of representable values by 2^n

Intellectual Property

A creative work (song, video, artwork) that the creator can apply for copyright, trademark, or patent depending on the work. Even if you don’t apply for copyright, you are still considered the original owner

Copyright

A license proving ownership of an intellectual property. “All rights reserved” means that anyone trying to use the IP must ask the owner for permission

Creative Commons

A more chill copyright license (easier to register than a full copyright). Allows owners to pre-approve some usage of their IP. Creative Commons’ website can be used to see IP’s and their pre-established usages.

What is the Internet?

A network of networks

Who owns the Internet?

Nobody and Everybody

Why does the internet work no matter where you are or what device you use?

All devices use the same protocols to communicate

What is the purpose of an IP Address?

Gives your computer a unique identity/location

The internet is often described as both redundant and fault tolerant. What does that mean?

Redundancy: There are multiple paths for data to travel (backup routes and systems in place)

Fault Tolerant: Ability of the system to keep functioning even when certain parts fail

What is the DNS and why is it important?

• Address book of websites and their

• Addresses. Allows users to connect to websites

What is Internet Protocol(IP)?

Basic communication protocol. Makes each connected device have an IP Address

What is User Datagram Protocol (UDP)?

Protocol to send large packets by breaking them into smaller packets; NO ERROR CHECKING

• routers along the network to decide where packets go

• prioritizes speed over reliability

• prevalent in things like online gaming and streaming

• connectionless (basically just dumps them all)

What is Transfer Control Protocol (TCP)?

Protocol to send large messages by breaking it into smaller packers; HAS ERROR CHECKING

• numbers the smaller packets

• routers along the network to decide where packets go

• Recipient receives packets, sends confirmation messages back to the sender

• Sender will resend any packets that it doesn’t receive a confirmation for.

• Recipient uses packet numbers to rearrange data into the correct order

• prevalent in email, web browsing, and file transfer

What is HyperText Transfer Protocol (HTTP)?

Protocol to define how communication works between a computer and a website.

• user makes a request for the server, and then the server follows HTTP protocol and sends a response back from the website to the user

How does a computer connect to a website?

• It makes an HTTP request and asks the DNS for the IP address

• DNS checks the records and/or asks other servers

• DNS sends IP address back to computer, which makes a GET request

• website sends back information for the user to display