Sustainability of Digital Formats: Planning for Library of Congress Collections

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Expert Witness Disk Image, ASR SMART

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Format Description Properties Explanation of format description terms

Identification and description Explanation of format description terms

Full name Expert Witness Compression Format, ASR SMART

Version of the EWF bitstream image format from ASR Data (SMART brand), generally similar to the description offered in EWF_Family.

EWF_SMART files contain four sections:

  • Header section
  • Volume section
  • Table section
  • Next and Done section
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

Local use Explanation of format description terms

LC experience or existing holdings  
LC preference  

Sustainability factors Explanation of format description terms

Disclosure Fully documented. Proprietary format developed by ASR Data. Documentation freely available; formerly on the ASR Data Web site (, now available at the Internet Archive. Same documentation also available on Simson Garfinkel's Forensics Wiki.
    Documentation Internet Archive copy at various URLs, including; Forensics Wiki version at
Adoption Not investigated at this time. 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 EWF_E01 and AFF (description forthcoming) are most frequently employed.
    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

Quality and functionality factors Explanation of format description terms

File type signifiers and format identifiers Explanation of format description terms

Tag Value Note
Filename extension s01
Filename extensions for the first 99 content segments are .s01, .s02, through .s99; followed by .saa, .sab, and so on.
Magic numbers Hex: 45 56 46 09 0D 0A FF 00
From Gary Kessler's File Signatures Table.

Notes Explanation of format description terms


Format specifications Explanation of format description terms

Useful references


Last Updated: 12/27/2022