Sustainability of Digital Formats: Planning for Library of Congress Collections |
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Introduction | Sustainability Factors | Content Categories | Format Descriptions | Contact |
Full name | Expert Witness Compression Format, EnCase L01 Logical |
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Description |
First version of the EWF logical evidence file image format from Guidance Software (EnCase brand), generally similar to the description offered in EWF_Family. This and the counterpart EWF_E01 format offer three levels of compression: "no," "good," and "best." EWF_L01 files contain 13 sections; the first four are carried over from EWF_SMART; the next nine are shared with EWF_E01; and the final two are new additions:
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Production phase | Typically used for data analysis and not part of a process to create new content. May be used to archive data. |
Relationship to other formats | |
Subtype of | EWF_Family, Expert Witness Format (EWF) Family |
Has later version | EWF_Lx01, Expert Witness Format, Encase Lx01 Logical |
LC experience or existing holdings | |
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LC preference |
Disclosure | Open documentation produced via reverse engineering by Joachim Metz. |
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Documentation | EWF specification: Expert Witness Compression Format specification |
Adoption | In archives (as distinct from legal and law enforcement settings), where tools like Bit Curator and FTK Imager are in wide use, user comments suggest that bitstream formats like EWF_E01 and AFF (description forthcoming) are more widely used than logical formats like EWF_L01. |
Licensing and patents | Not investigated at this writing. |
Transparency | See EWF_family |
Self-documentation | See EWF_family |
External dependencies | None |
Technical protection considerations | See EWF_family |
Tag | Value | Note |
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Filename extension | L01 |
Filename extensions for the first 99 content segments are .L01, .L02, through .L99; followed by .LAA, .LAB, and so on. |
Magic numbers | Hex: 4C 56 46 09 0D 0A FF 00 ASCII: LVF...ΓΏ. |
From Gary Kessler's File Signatures Table. |
Pronom PUID | fmt/804 |
General |
Joachim Metz's analysis highlights the details of this format, including variation in the structure of .L01 headers, in part depending on the version of the EnCase tool used to create the file (pp. 5-15, esp. p. 8-9 and 15), and variations in the volume section according to the creating application (pp. 18-20). |
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History |
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