Folders and Files

Purpose

Understanding how CAB files organize content using folders and files.

References

Folder Concept

What is a Folder?

A folder in CAB is NOT a directory. It’s a compression unit that groups files sharing the same compression method and state.

Cabinet:
┌────────────────────────────────────────┐
│ Folder 1 (MSZIP compression)          │
│   ├── file1.txt                        │
│   ├── file2.txt                        │
│   └── file3.txt                        │
├────────────────────────────────────────┤
│ Folder 2 (LZX compression)            │
│   ├── data1.bin                        │
│   └── data2.bin                        │
└────────────────────────────────────────┘

Why Use Folders?

  • Compression efficiency: Dictionary shared across files

  • Different algorithms: Optimal compression per file type

  • Streaming: Decompress folder-by-folder

File Organization

File Ordering

Files are stored sequentially within folders. The order matters for compression efficiency.

Spanning Cabinets

Files can span multiple cabinets in multi-part archives.

Bibliography