Year 10 - Computing
Run length encoding
Data compression
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This pupil-friendly study guide includes a unit summary, clear notes, common mistakes, and quick questions with answers.
Unit Summary
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.
Lesson Summary
You will learn to describe and use run length encoding to compress data.
Key Notes
- Run length encoding is a lossless data compression technique that reduces the size of repeating sequences of data.
- Run length encoding uses the concept of redundancy to reduce file size.
- Redundancy is about the repetitive information within a data set, which can be removed without losing essential meaning.
- Run length encoding may not always reduce file size and may not be suitable for all applications.
Vocabulary To Learn
- run length encoding: a common type of lossless compression
- data pattern: a recurring trend, relationship, or structure found within a set of data
- redundancy: repeated or extra data that isn't needed
Common Mistakes To Avoid
- Run length encoding always reduces file size.
3 Quick Questions (With Answers)
1. Describe the system or process from this lesson in clear steps.
Run length encoding is a lossless data compression technique that reduces the size of repeating sequences of data. Run length encoding uses the concept of redundancy to reduce file size.
2. Define this computing term and give one practical example. 'run length encoding'
a common type of lossless compression. Add one real device or system example to prove understanding.
3. Correct this common computing misconception.
Mistake: Run length encoding always reduces file size. Correction: Run length encoding only works well when data has long repeated patterns. If data is random or has frequent changes, RLE may not reduce the file size and can even make it bigger. For example, compressing "HELLO" with RLE results in "1H1E2L1O".
More Lessons In This Unit
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