IGCSE ICT – File Management and Reducing File Sizes (Syllabus 11.1 & 11.2)

1. Why Reduce File Sizes? – Assessment Objective AO2 (Apply knowledge)

• Limited storage on computers, USB sticks, servers, or cloud accounts.
• Faster upload/download, especially on low‑bandwidth connections.
• Lower data‑transfer costs and reduced risk of exceeding email attachment limits (usually 10–25 MB).
• Helps keep backups and archives manageable.

2. Key Concepts

2.1 File Management (Syllabus 11.1)

• Hierarchical folder structures – organise files in folders and sub‑folders for easy retrieval.
• File‑naming conventions – use clear, consistent names (no spaces, avoid special characters, include version numbers).
• Saving in appropriate formats – choose the correct file type for the intended use (e.g., .docx, .pdf, .xlsx, .csv, .txt, .jpg, .png, .html).
• Multiple‑format saving – keep a master copy in the native format (editable) and export a copy for distribution (e.g., .docx → .pdf).

2.2 Compression – Lossless vs. Lossy (AO1 & AO2)

Note: In the IGCSE practical tasks you will only be required to use lossless compression for documents and programme files. Lossy formats are relevant when editing images for a presentation (see Section 12).

3. Lossless Compression Formats (Exam‑relevant)

4. Creating a .zip Archive – Step‑by‑Step (AO2)

4.1 Windows 10/11

1. Select the files or folders you wish to compress.
2. Right‑click → Send to → Compressed (zipped) folder.
3. A .zip file appears in the same location. Rename if required.

4.2 macOS (Ventura, Monterey, etc.)

1. Select the items.
2. Control‑click (or right‑click) → Compress “<item name>”.
3. An Archive.zip file is created in the same folder.

4.3 Linux – GUI (e.g., Ubuntu)

1. Select the files/folders.
2. Right‑click → Compress….
3. Choose “.zip” as the format, set a name, and click Create.

4.4 Linux – Terminal (optional)

zip -r archive_name.zip folder1 file2.docx

5. Creating a .rar Archive – Step‑by‑Step (AO2)

RAR archives require a third‑party utility such as WinRAR, 7‑Zip, or PeaZip. The example below uses WinRAR; the same principles apply to the other tools.

1. Install the chosen utility (download from the official site).
2. Select the files/folders to compress.
3. Right‑click → Add to archive….
4. In the dialog box:

   • Archive format: choose RAR.
   • Compression level: Best for maximum reduction (or Normal for faster processing).
   • Password: set one if you need encryption (AES‑256).
   • Split to volumes: optional – specify size (e.g., 10 MB) for large archives.

5. Click OK. The .rar file appears in the same location.

6. Extracting Files from an Archive (AO2)

• .zip

  • Windows: Right‑click → Extract All… or double‑click and drag files out.
  • macOS: Double‑click to open with Archive Utility, then drag files out.
  • Linux GUI: Right‑click → Extract Here.
  • Linux terminal: unzip archive.zip.

• .rar

  • Open with the same utility that created it (WinRAR, 7‑Zip, PeaZip).
  • Choose Extract To… and select a destination folder.
  • Linux terminal: unrar x archive.rar.

7. Cross‑Topic Reminders (Links to Other Syllabus Sections)

• 12 – Images: When compressing a presentation that contains images, first edit the images (crop, resize, adjust brightness/contrast) before adding them to the archive. Use lossless formats (.png) for graphics that need exact reproduction and lossy formats (.jpeg) only when a small quality loss is acceptable.
• 13 – Layout & 14 – Styles: Keep any document styles (headings, tables, footers) intact by compressing the original .docx file rather than an exported .pdf unless the final recipient only needs a read‑only version.
• 15 – Proofing: Run spell‑check and grammar tools before compressing a document; once archived, errors are harder to spot.
• 16 – Graphs & 17 – Documents: Export spreadsheets with embedded charts as .xlsx (editable) and also as .pdf for distribution; compress both files together to keep them linked.
• 18 – Databases: When sending a database, include the data file (e.g., .accdb) and the related forms/reports in the same archive to preserve relationships.
• 19 – Presentations: A presentation folder may contain a .pptx file, linked images, and videos. Compress the whole folder so links remain functional.
• 20 – Spreadsheets: Preserve formulas by compressing the native .xlsx file; avoid converting to .csv unless only raw data is needed.
• 21 – Website authoring: A website consists of many files (HTML, CSS, images, scripts). Always compress the entire website folder to keep the directory structure intact.

8. Safety & Security (Syllabus 8)

• Never open an archive from an unknown source without scanning it with anti‑malware software.
• Use strong passwords (AES‑256) for sensitive data; keep the password separate from the archive.
• Store backup copies of both the original files and the compressed archive in different locations (e.g., cloud + external drive).
• When sharing via email, confirm the recipient’s ability to open the chosen format (ZIP is universally supported; RAR may require the recipient to install a utility).

9. Audience & Communication Considerations (Syllabus 9‑10)

• Technical audience (e.g., teachers, IT staff): Use .rar or .7z for higher compression and optional encryption.
• Non‑technical audience (e.g., classmates, parents): Prefer .zip because it can be opened without installing extra software.
• Explain any password you set in a separate, secure message (e.g., verbally or via a trusted chat).

10. Best‑Practice Checklist – Mapped to the Systems Life‑Cycle (AO3 – Evaluate)

1. Design – Decide which files need compression and choose the appropriate lossless format (.zip for compatibility, .rar/.7z for higher reduction or security).
2. Develop – Apply proper file‑naming conventions and organise files in a logical folder hierarchy.
3. Test – After creating the archive, extract a few files to verify integrity and that all links (e.g., in a website folder) work.
4. Implement – Distribute the archive using the chosen method (email, cloud link, USB) and provide any required passwords separately.
5. Evaluate – Reflect on the compression ratio achieved, processing time, and whether the chosen format met the audience’s needs. Record any issues (corruption, incompatibility) for future improvement.

11. Common Pitfalls & How to Avoid Them (AO1 & AO3)

• Compressing already compressed files (e.g., JPEG, MP3) – yields little size reduction. Resize or convert images before compression if needed.
• Using the highest compression level indiscriminately – can dramatically increase processing time with minimal extra gain. Test “Normal” first; only switch to “Best” for very large archives.
• Choosing a single archive format for all recipients – may cause compatibility problems. Match the format to the audience’s capabilities.
• Not verifying the archive – leads to corrupted files being sent. Always extract a sample file before distribution.
• Storing only the compressed version – if the archive becomes corrupted you lose the original data. Keep an uncompressed backup in a separate location.

12. Quick Revision Summary (AO1‑AO3)

• Identify why a file needs to be reduced (storage, speed, cost, email limits).
• Recall the difference between lossless and lossy compression and the exam‑relevant formats.
• Choose the appropriate format:

  • .zip – universal compatibility.
  • .rar/.7z – higher compression, strong encryption, volume splitting.

• Apply correct OS‑specific steps to create the archive.
• Test the archive by extracting a sample file.
• Maintain original copies and backup the archive in separate locations.
• Consider audience, safety, and the systems life‑cycle when planning, creating, and sharing compressed files.