Storing data

Question 1

what are all the measures of data going from smallest to largest

Answer 1

Bit
Nibble
Byte
Kilobyte
megabyte
gigabyte
terabyte
petabyte

Question 2

how do computers store data

Answer 2

using ones and zeroes

Question 3

what 2 types of data storage are used by computers

Answer 3

Binary
Hexadecimal

Question 4

what is a character set

Answer 4

a collection of characters a computer recognises from their binary representation

Question 5

what are the 2 main characters’ sets

Answer 5

ASCII
Unicode

Question 6

how are images stored

Answer 6

images are stored as bitmaps which are made up of pixels
the colour of each pixel is presented by binary code

Question 6

why is Unicode better than ASCII

Answer 6

it is larger so it covers more languages and symbols

Question 7

what 2 factors affect the filesize of an image

Answer 7

colour depth
resolution

Question 8

what is the colour depth of an image

Answer 8

the number of bits that is used to represent the colour for each pixel

Question 9

what is the resolution of an image

Answer 9

the number of pixels

Question 10

what is metadata and what is its purpose

Answer 10

data about an image that helps the computer recreate the image on the screen from the binary data

Question 11

what are 4 examples of metadata

Answer 11

file format
location
date
height
width
colour depth

Question 12

how is sound sampled

Answer 12

1. a microphone records the sound as an analogue signal
2. the analogue signal needs to be converted into digital data so that computers can read and store sound files.
3. this is done by sampling where at regular intervals the computer will take a reading of the wave of information such as amplitude. this can be converted into binary data

Question 13

what are 2 factors that affect the quality of a sound file

Answer 13

sample rate
bit depth

Question 14

what is the formula for the bit rate

Answer 14

sample rate/bit depth

Question 15

how does the sample rate

Answer 15

the higher the sample rate the more samples will be taken of the sound wave per second which means that the digital sound wave will be more accurate

Question 16

how does bit dept affect the quality of a sound wave

Answer 16

bit depth is the number of bits available for each sample increasing bit depth means the digital file can pick up quieter sounds

Question 17

what are the 2 types of compression

Answer 17

lossy
lossless

Question 18

how does lossy compression work

Answer 18

it permanently removed data from the file to lower file size

Question 19

how does lossless compression work

Answer 19

temporarily lowers filesize by using an algorithm to remove unscary data

Question 20

what are 2 advantages of lossy compression

Answer 20

• greatly reduce the file size
• commonly used

Question 21

what are 3 disadvantages of lossy compression

Answer 21

file cannot be reverted
cannot be used on text files
lowers quality by a lot

Question 22

what are 2 advantages of losseless compression

Answer 22

the file can be reverted
can be used on text or software files

Question 23

what is a disadvantage of lossless compression

Answer 23

will only lower file size by a bit