Know and understand characteristics and uses of file formats including css, csv, gif, htm, .jpg, .pdf, .png, .rtf, .txt, .zip, .rar

11. File Management – Characteristics and Uses of Common File Formats

This set of notes introduces the most frequently encountered file formats in ICT. Understanding the purpose, typical applications and key characteristics of each format helps you to choose the right one for a given task and to manage files efficiently.

Why Knowing File Formats Matters

• Ensures compatibility between software and devices.
• Optimises storage space and download times.
• Supports accessibility and data exchange.
• Helps protect data integrity when compressing or archiving.

Summary Table of File Formats

Detailed Characteristics

1. Cascading Style Sheets – .css

• Plain‑text file containing a set of rules that describe how HTML elements should be displayed.
• Rules consist of a selector and a declaration block (property: value;).
• Can be linked externally, embedded in <style> tags, or added inline.
• Facilitates site‑wide design changes without editing each HTML page.

2. Comma‑Separated \cdot alues – .csv

• Each line represents a row of data; fields are separated by commas (or semicolons in some locales).
• Ideal for importing/exporting data between spreadsheets (e.g., Excel) and databases.
• No formatting – only raw data.
• Can be opened in any text editor or spreadsheet program.

3. Graphics Interchange Format – .gif

• Supports animation by storing multiple frames.
• Limited to 256 colours – best for simple graphics, logos, icons.
• Uses lossless LZW compression; file size remains relatively small for simple images.
• Does not support partial transparency (only binary transparency).

4. HyperText Markup Language – .htm / .html

• Markup language that structures web content using tags such as <h1>, <p>, <a>.
• Can reference external resources: CSS (link), JavaScript (script), images (img).
• Browsers interpret the markup to render a visual page.

5. JPEG – .jpg / .jpeg

• Lossy compression reduces file size by discarding some image data.
• Best for photographs where subtle colour variations are more important than sharp edges.
• Compression level is adjustable; higher compression = lower quality.
• Does not support transparency.

6. Portable Document Format – .pdf

• Preserves layout, fonts, images, and vector graphics across devices.
• Can be secured with passwords and permissions (e.g., printing, editing).
• Supports interactive elements: hyperlinks, forms, annotations.
• Widely used for manuals, e‑books, official documents.

7. Portable Network Graphics – .png

• Lossless compression retains original image quality.
• Supports an 8‑bit (256‑colour) palette and a 24‑bit true‑colour mode.
• Alpha channel allows varying levels of transparency – ideal for overlays.
• File size larger than JPEG for photographic images but smaller for graphics with large uniform areas.

8. Rich Text Format – .rtf

• Encodes text with simple formatting (bold, italics, fonts, colours).
• Cross‑platform – readable by Microsoft Word, LibreOffice, Google Docs, and many other editors.
• Does not support complex layout features such as tables of contents or advanced styles.

9. Plain Text – .txt

• Contains only characters; no formatting codes.
• Ideal for source code, configuration files, notes.
• Universal compatibility – can be opened on any operating system.
• Smallest possible file size for textual information.

10. ZIP Archive – .zip

• Combines multiple files/folders into a single container.
• Uses lossless compression algorithms (e.g., Deflate) to reduce size.
• Supports password protection and AES encryption.
• Native support in Windows, macOS, and many Linux distributions.

11. RAR Archive – .rar

• Proprietary format developed by Eugene Roshal.
• Often achieves higher compression ratios than ZIP, especially for multimedia files.
• Can split large archives into smaller volumes for easier distribution.
• Requires specific software (WinRAR, 7‑Zip with RAR plugin) to create or extract.

Practical Tips for Managing These Files

1. Always keep a backup of original, uncompressed files before creating archives.
2. When sharing images on the web, use .png for graphics with transparency and .jpg for photographs.
3. Store data tables as .csv when you need to import them into spreadsheets or databases.
4. Use .css files to separate design from content – makes site updates faster.
5. Compress large groups of files into a .zip before emailing to reduce attachment size.
6. When creating documents that must retain exact layout, export or save as .pdf.