Archives & Compression (ZIP/RAR)

Connected clusters

• Document Workflows
• Mobile Printing
• PDF Ecosystem
• Printing & Document Standards

In the archive

• Guides
• Workflows
• Tools

Pages in this cluster

• Legal Document Archives
• Continuous Inkjet Printing
• AFP (Advanced Function Presentation)
• OCR for Receipts
• OCR for Healthcare Documents
• OCR for Archives
• Compression Before OCR
• QR and 2D Code Recognition
• Digital Preservation
• Medical Record Archives
• Government Records Archives
• Color gamut and gamut mapping

Planned coverage

• What Is a ZIP File? — Defines the ZIP container format, what it stores, and how it bundles plus compresses multiple files into one archive.
• What Is a RAR File? — Explains the proprietary RAR archive format, its typical uses, and why it needs specific software to create and open.
• What Is the 7z Format? — Describes the open 7z format and its association with the 7-Zip tool, including its use of LZMA-family compression.
• What Is a TAR Archive? — Explains TAR as a Unix bundling format that stores files without compressing, and why it is paired with gzip or bzip2.
• What Is gzip? — Covers the gzip format and its DEFLATE-based single-stream compression as defined in RFC 1952.
• What Is File Compression? — Foundational explainer distinguishing archiving from compression and introducing lossless data reduction.
• Lossless vs. Lossy Compression — Contrasts the two families of compression and explains why archive formats are strictly lossless.
• How DEFLATE Compression Works — Explains the DEFLATE algorithm (RFC 1951) as the combination of LZ77 dictionary matching and Huffman coding.
• LZ77 and Dictionary-Based Compression — Describes how sliding-window dictionary methods replace repeated byte sequences with back-references.
• Huffman Coding Explained — Introduces entropy coding and how variable-length codes shorten frequently occurring symbols.
• The History of the ZIP Format — Traces ZIP from PKWARE's PKZIP and the public APPNOTE specification to its role as a universal container.
• ZIP vs. RAR: How the Formats Differ — Vendor-neutral comparison of open ZIP versus proprietary RAR across openness, tooling, and features like solid archives.
• Understanding Compression Ratios — Explains what a compression ratio measures and why results depend heavily on the input data's redundancy.
• What Is a Checksum? — Explains CRC-32 and integrity checks stored in archives to detect corruption during storage or transfer.
• How ZIP Encryption Works — Describes legacy ZipCrypto versus AES-based encryption for password-protected ZIP archives, at a conceptual level.
• What Is a Solid Archive? — Explains solid compression in RAR and 7z, where files are treated as one stream to improve ratio, with its trade-offs.
• Self-Extracting Archives Explained — Describes SFX archives that bundle an extractor executable, and the portability and safety considerations involved.
• Multi-Volume and Split Archives — Explains splitting large archives into numbered volumes for size-limited media or transfer, and how they rejoin.
• tar.gz and Tarballs Explained — Explains the common tar.gz/tgz combination of TAR bundling plus gzip compression widely used on Unix systems.
• What Is Zstandard (zstd)? — Introduces the modern zstd lossless algorithm, its dictionary approach, and where it fits among older formats.
• Compressing Files for Email and Transfer — Practical, tool-neutral workflow for archiving multiple files to share, with notes on size limits and integrity.
• Using Archives for Backups — Explains how archive formats support backup by consolidating files, preserving structure, and verifying integrity.
• What Is bzip2? — Covers bzip2's Burrows-Wheeler-transform approach and how it differs from DEFLATE-based gzip.
• Common Archive Formats Compared — Overview page mapping ZIP, RAR, 7z, TAR, and gzip by openness, compression method, and typical platform.