3.3: data storage and compressions

Question 1

kilobyte

Answer 1

1000 kB

Question 2

megabyte

Answer 2

1000² MB

Question 3

gigabyte

Answer 3

1000³ GB

Question 4

terabyte

Answer 4

1000⁴ TB

Question 5

kibibyte

Answer 5

1024 KiB

Question 6

mebibyte

Answer 6

1024² MiB

Question 7

gigibyte

Answer 7

1024³ GiB

Question 8

tebibyte

Answer 8

1024⁴ TiB

Question 9

compression methods

Answer 9

lossless
lossy

Question 10

advantages of data compression

Answer 10

makes storage more efficient
allows you to upload and download files faster

Question 11

lossless compression

Answer 11

do not lose any data
data can be reversed to what it was before
use shorthand to store data

Question 12

examples of lossless compression

Answer 12

ZIP file
RLE (run length encoding)

Question 13

ZIP file

Answer 13

if you add files to a ZIP they take up less space but are exactly the same when you unzip them

Question 14

RLE

Answer 14

RLE encodes data items and how long it runs

Question 15

example of RLE

Answer 15

55555511111333
turns into:
(6 5) (5 1) (7 3)

Question 16

lossy compression

Answer 16

removes data that us unnecesary
data cannot be restored to what it was before as data is lost

Question 17

use of lossy compression

Answer 17

multimedia
for audio files by removing sounds outside the range that humans can hear

Question 18

example of lossy compression

Answer 18

MP3
this means less space required and faster streaming
JPEG
decreases size of image