Data Compression/Optimisation

Question 1

What is optimisation?

Answer 1

Finding the best compromise between file size and quality

Question 2

How can you compress text files?

Answer 2

Replace common letter combinations with a symbol, e.g. ‘at’ with ‘@’

Question 3

How can you compress graphic files?

Answer 3

Change bitmap images into JPEG and GIF (reduces the number of colours)

Question 4

How can you compress sound files?

Answer 4

Reduce the bit rate (may reduce quality)

MP3 and WMA

Question 5

What is a zip file?

Answer 5

A general purpose program that can compress any file

Question 6

State the advantages and disadvantages of data compression

Answer 6

Advantages:
Save more data is a given storage space
Faster to send, copy and download the file

Disadvantages:
May lose quality
Makes it easy to copy and download files making it faster for hackers