Computer Science

a set of step-by-step instructions to solve a problem

how effectively compression reduces the size of data while maintaining its usability

accepting a limitation to achieve a beneficial outcome

Comparing compression algorithms

Measurements of storage

The need for compression

Lossy and lossless compression

Compression ratios

Practical applications of compression

In this unit pupils will be introduced to the concept of data compression and why it is needed. The will compare lossy and lossless compression methods and their typical uses. They will have the opportunity to compression methods such as run length encoding (RLE) and Huffman coding.

Data compression

a set of step-by-step instructions to perform a task

how effectively compression reduces file size while ensuring usability

the limitations and choices faced when optimising competing factors

how quickly data can be compressed or decompressed

It balances file size reduction with usability.

Smaller files might lose important details.

Why isn’t the smallest file size always the best result for compression?

What is a limitation of some compression methods?

Compare the speeds of different methods and the resulting file sizes expected.

Put these steps in order for comparing compression methods:

What does encoding mean in data compression?

What is used to visually represent the encoding scheme in Huffman coding?

What lossless compression technique reduces file size by encoding repeating sequences of data?

What term describes repeated or extra data that can be removed without losing essential meaning?

to assign shorter bit sequences to more frequent characters

Comparing compression algorithms

Lesson outcome