Data storage

Question 1

How does lossy compression work?

Answer 1

• A compression algorithm is used
• Removes unnecessary data from the file
• Data is permanently removed and the original file cannot be reinstated

Question 2

How does lossless compression work?

Answer 2

• A compression algorithm is used
• Repeating patterns are identified which are replaced by a value and indexed
• No data is permanently removed and original file can be re-instated

Question 3

When is lossless compression most suitable?

Answer 3

For text files e.g. source code where accuracy and all data/info is important

Question 4

How is lossy compression applied to music, photos and videos

Answer 4

music: removes sounds at frequencies humans can’t hear/background noise - or reducing sample rate
photo: removes pixels, colors and image resolution that is not noticed by humans