Sustainability of Digital Formats: Planning for Library of Congress Collections
Sustainability of Digital Formats: Planning for Library of Congress Collections |
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| Introduction | Sustainability Factors | Content Categories | Format Descriptions | Contact | |
| Full name | RAR Archive File Format, Version 3 |
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| Description |
Roshal ARchive format version 3 (RAR3) is said to be built off RAR1.5 but there is no publicly available information for RAR1.5 to compare it to. Comments welcome. Structurally, RAR3 is comprised of a marker block, archive header and file header(s). These can be augmented as needed with optional comment headers, extra information blocks and subblocks. RAR3 declares a new block type, authenticity information, that was not present in RAR2. See RAR_Family for details on the file structure. A key feature of RAR3 is the switch from proprietary and not open compression algorithms to PPMII and Lempel-Ziv (LZSS) algorithms. Wikipedia states that "encryption now uses cipher block chaining (CBC) instead of Advanced Encryption Standard (AES)" but documentation from WinRAR declares AES for RAR4 and RAR5. |
| Production phase | See RAR_Family |
| Relationship to other formats | |
| Subtype of | RAR_Family, RAR Archive File Format Family |
| Has earlier version | RAR2, RAR Archive File Format, Version 2 |
| Has later version | RAR4, RAR Archive File Format, Version 4 |
| LC experience or existing holdings | See RAR_Family. |
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| LC preference | None |
| Disclosure | See RAR_Family |
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| Documentation | See RAR_Family |
| Adoption | See RAR_Family |
| Licensing and patents | See RAR_Family |
| Transparency | See RAR_Family |
| Self-documentation | See RAR_Family |
| External dependencies | See RAR_Family |
| Technical protection considerations | See RAR_Family |
| Other | |
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| Bundling/compression | See RAR_Family |
| Tag | Value | Note |
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| Filename extension | See note. | See RAR_Family |
| Internet Media Type | See note. | See RAR_Family |
| File signature | Hex: 52 61 72 21 1A 07 00 ASCII: Rar! |
Wikipedia states that this magic number is applicable for RAR1.5 - RAR4 although Gary Kessler's File Signature Table and RAR 5.0 archive format tech note only specifically list this magic number for RAR4, not earlier versions. Acritum Software's description of RAR version 3.93 (not described at this site) lists this value for all versions since RAR1.5. |
| Pronom PUID | See note. | No PUID as of March 2017. |
| Wikidata Title ID | See note. | See RAR_Family. |
| General | See RAR_Family. |
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| History | See RAR_Family. |
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