1.2.5 - Compression

Question 1

Why do we need compression?

Answer 1

More data can be stored on a storage device and transferred quicker
- To reduce the number of bits in a file
- Increase storage capacity
- Making data transfer quicker

Question 2

What is lossy compression?

Answer 2

Some of the data is completely lost and cannot be recovered
Loss of data is not important

Question 3

What does Lossy compression do?

Answer 3

Greatly reduces file size & the quality of images/sound

Question 4

What is Lossy compression suitable for?

Answer 4

• Images, sound and video
• Cannot be used on text/executable files

Question 5

What is Lossless compression?

Answer 5

None of the data is lost, just encoded differently
File will be restored to original state when uncompressed

Question 6

Why is Lossless compression good?

Answer 6

• It can be turned back into its original format
• Can be used on all types of data

Question 7

Which compression is less effective?

Answer 7

Lossless is less effective at reducing the file size

Question 8

What is Lossless compression most suitable for?

Answer 8

Documents & executable files