big idea #2 - test 1

topics

  • binary decimal conversions

  • roundoff, overflow error

  • lossless and lossy compression

  • b&w images and color images

  • intellectual property

content

bits and bytes

  • binary data → 1’s and 0’s; computer’s way of representing information

  • bits → smallest unit of information; computers store information through bits

  • bytes → a unit of digital information that consists of 8 bits

binary numbers

  • decimal system → human numbers (1-10)

  • binary system → computers represent decimal numbers through 1’s and 0’s

  • decimal → binary

  • binary → decimal

limitations of storing numbers

  • integer → any number that can be written without a fractional component

  • overflow roundoff → when the value of the number is too big to be written in the number of bits currently being used; shows a weird number, because it can’t show the actual number

    • ex: when milage makes it past 999999, it’ll just go back to 000000 and start over from there

  • roundoff error → when there are too many digits in the number, so it just rounds the number to fit the number of storage available

    • ex: when pi is written in a calculator, but when you try to check the value it just rounds it to 3.14159265 (or whatever place, it doesn’t matter, since it can’t write out the infinite digits of pi)

lossless compression

  • done by finding repeated sequences and replacing them with shorter representations

  • file sizes cannot be reduced by a large amount

lossy compression

  • does not decompress digital data back to 100% of the og file

  • loss of a quantity such as a frequency component or loss of noise

standard copyright

  • default rule: if you make something (art, music, writing, video, etc.), you automatically own the rights.

  • others can’t copy, sell, or remix it without your permission.

  • lasts a long time (life of creator + 70 years in many countries)

public domain

  • works that aren’t protected by copyright anymore

  • anyone can use it however they want

intellectual properties

  • set of licenses that let creators decide how others can use their work

  • types:

    • cc by → can be used if credit is given

    • cc by-sa → share and remix but keep the same license

    • cc by-nd → share but no changes allowed

    • cc by-nc → non-commercial use only

      • by → give credit

      • sa → share alike

      • nd → no derivatives

      • nc → non-commercial

black and white images

  • uses binary to determine which pixel is black or white (1-white, 0-black)

color images

  • uses RGB to create all colors