Memory & StorageKey Facts
Lossless Compression - Perfect Recreation
Part of Compression — GCSE Computer Science
This key facts covers Lossless Compression - Perfect Recreation within Compression for GCSE Computer Science. Revise Compression in Memory & Storage for GCSE Computer Science with 15 exam-style questions and 16 flashcards. This topic appears regularly enough that it should still be part of a steady revision cycle. It is section 3 of 11 in this topic. Use this key facts to connect the idea to the wider topic before moving on to questions and flashcards.
Topic position
Section 3 of 11
Practice
15 questions
Recall
16 flashcards
Lossless Compression - Perfect Recreation
What is Lossless Compression?
- Reduces file size WITHOUT losing any data
- Original file can be perfectly reconstructed
- Uses patterns and redundancy to make files smaller
- Typical reduction: 30-70% smaller (varies by file type)
When to Use Lossless:
- Text documents: Word files, PDFs, code - every character matters
- Programs/executables: One wrong bit = program crashes
- Medical images: X-rays, MRI scans - diagnosis requires exact detail
- Legal documents: Contracts, evidence - must be identical to original
- Scientific data: Research data, measurements - accuracy critical
Common Lossless Formats:
- ZIP, RAR, 7z: General file compression/archiving
- PNG: Lossless image format (screenshots, diagrams, graphics with text)
- FLAC: Lossless audio (music archiving, audiophiles)
- GIF: Simple animations and graphics (limited to 256 colors)
- GZIP: Web compression (HTML, CSS, JavaScript files)