Digital Information: Converting Analog Data to Binary

Question 1

can you store more BIG files in a computer or small files

Answer 1

small

Question 2

compression

Answer 2

algorithms to reduce the amount of space needed to represent a file

Question 3

how many types of compression are there and what are they

Answer 3

lossless and lost (2)

Question 4

lossless compression

Answer 4

algorithms reduce the size of files without losing any information in the file

Question 5

lossy compression

Answer 5

algorithms reduce the size of files by discarding the less important information in a file

Question 6

what type of compression affects file quality? explain why

Answer 6

lossy because some info is taken away from the files while in lossless they are reduced without taking anything away

Question 7

how do computers compress text

Answer 7

by finding repeating phrases (common) and making them a sign

Question 8

example of how text is compressed in real life

Answer 8

like how people say u instead of you or lol instead of out loud

Question 9

what can be compressed

Answer 9

things that repeat at least twice in a sequence

phrases, words, parts of words (th) [like the in the, this, thought,etc.]

Question 10

all text files can be compressed
true or false

Answer 10

false

Question 11

compression always makes a smaller file
true or false

Answer 11

false because sometimes it can require more bytes

Question 12

how do computers compress image files (what process)

Answer 12

run length encoding (RLE)

Question 13

why is it particularly important to compress image files

Answer 13

bc they’re like super fat files that take up a bunch of space

Question 14

how does RLE work

Answer 14

the computer replaces each row (of the image – like the little boxes) with numbers that say how many consecutive pixels are the same color (like 5 reds)

Question 15

RLE always starts coding with the number of _____ pixels

Answer 15

white

Question 16

if a row does not start with the color white then how is RLE coded

Answer 16

it just begins with 0 whites

Question 17

how would a row with: 3 white pixels, 2 red pixels, 5 white pixels, 2 red pixels, then 4 white pixels be represented

Answer 17

with the bit representations of the numbers 3,2,5,2,4

Question 18

can you make a perfect representation of an image from RLE coding

Answer 18

yes

Question 19

does RLE coding always reduce the size of a file? why or why not?

Answer 19

no because it is very rare that the same exact color repeats over and over again so you will need different combinations of 0 and 1 to show different numbers so it would be super long and so much stuff yk which would be a bigger file

Question 20

where is RLE used irl

Answer 20

fax machines

Question 21

why do fax machines use RLE

Answer 21

bc they only print in black and white

Question 22

Huffman coding

Answer 22

assigning shorter codes to more frequently occurring characters and longer codes to less frequent characters

Question 23

all types of compression code in what

Answer 23

bits

Question 24

example of huffman coding

Answer 24

A and G are assigned one more bit because they are the least common letters in the sequence.

If they were only assigned 2 bits, there would be confusion when decoding messages. Imagine we had the following code:
a - 01
c - 00
g - 10
t - 1

If I asked you to decode the message 101, it would not be clear whether the original message was ta or gt.