PRONOM Signature Development Utility

Output DROID compatible file format signature files using PRONOM syntax
Homepage:	https://github.com/exponential-decay/signature-development-utility
License:	Open source (see URL above)
Platforms:	Golang + PHP + JQuery + Javascript + text/html
Function:	File Format Identification

Description

Utility to enable the creation of DROID compatible signature files using PRONOM regular expression syntax. The tool outputs in an XML format compatible with DROID 4 upwards (including DROID 5 and 6). Three sequences can be combined to create a single file format signature. Signature files can be concatenated manually if more complex collections are required for testing.

Version 2: FFDev.info

Version 2 of the utility was released in October 2020. The utility adds support for Container Signature sequences. The first iteration is bootstrapped to the original utility which has already been well proven.

Hosting

Version 2 is hosted on:

• http://ffdev.info

Version 1: PRONOM signature development utility

The original code for version 1 of the utility is still available in a branch on Github.

Hosting

Version 1 is hosted at exponentialdecay.co.uk and The National Archives, UK:

• Signature development utility at The National Archives, UK
• Signature development utility at exponentialdecay.co.uk

Using its Output

DROID

The signature development utility output can be directly uploaded to DROID via its 'Install Signature File' mechanism. Be sure to then select the new file from 'Preferences'. Container signatures need to be added via the users /home/<username>/.droid6 directory. On Windows the user's home folder can be found under Users in 'C:'.

Siegfried

Siegfried is a useful tool for testing because it can combine a new signature file from this utility with all the other signatures in the PRONOM corpus, plus its many others.

Instructions for Linux

We use a utility called Roy to extend signature files. This is installed alongside Siegfried.

To extend a signature file to include a custom signature file, we need to make sure that there is a 'custom' folder, where Roy can find it. We will need our signature to be on a path that looks as follows:

/home/{username}/siegfried/custom/{custom-dev-sig}.xml

Extending the signature file can then be completed in two stages:

1) Roy harvest

This will download PRONOM signature file reports. This is the most accurate way to run Siegfried. An alternative is to let Siegfried parse the DROID signature file, but this has shown to lead to some inconsistencies where PRONOM and DROID do not reflect each other entirely.

2) Roy build -extend {custom-dev-sig}.xml

Try Siegfried on a single file of the format we have created the signature for:

3) sf {custom-dev-format}.{ext}

The result will be:

---
siegfried   : 1.7.6
scandate    : 2017-10-25T23:35:31+13:00
signature   : default.sig
created     : 2017-10-25T23:23:59+13:00
identifiers : 
  - name    : 'pronom'
    details : 'DROID_SignatureFile_V91.xml; container-signature-20170330.xml; extensions: {custom-dev-sig}.xml'
---
filename : '{custom-dev-format}.{ext}'
filesize : 1492992
modified : 2017-10-22T16:02:13+13:00
errors   : 
matches  :
  - ns      : 'pronom'
    id      : 'dev/1'
    format  : '{custom-dev-format}'
    version : '1.0'
    mime    : 'application/{custom-dev-format}'
    basis   : 'extension match img; byte match at 1024, 32'
    warning : 

RDF

The tool's output suggests a potential RDF representation of a DROID signature (NB. this is a version 1 option only).

RDF from the utility looks as follows:

<?xml version="1.0" encoding="UTF-8"?>
<rdf:RDF xmlns:xsd="http://www.w3.org/2001/XMLSchema#" xmlns:sigdev="http://nationalarchives.gov.uk/preservation/sigdev/signature/" xmlns:bytes="http://nationalarchives.gov.uk/preservation/sigdev/signature/byteSequence/" xmlns:rdf="http://www.w3.org/1999/02/22-rdf-syntax-ns#" xmlns:rdfs="http://www.w3.org/2000/01/rdf-schema#">
  <sigdev:DevelopmentSignature rdf:about="http://nationalarchives.gov.uk/preservation/sigdev/signature/ddc3ab7d-db41-49c5-b3fa-262ad83dd703">
    <rdfs:label>Development Signature</rdfs:label>
    <sigdev:version>1.0</sigdev:version>
    <sigdev:extension>ext</sigdev:extension>
    <sigdev:internetMediaType>text/x-test-signature</sigdev:internetMediaType>
    <sigdev:puid>dev/1</sigdev:puid>
    <sigdev:byteSequence>
      <rdf:Description rdf:about="http://nationalarchives.gov.uk/preservation/sigdev/signature/byteSequence/228c0626-3e0d-40bc-98d3-d897a21b20e1/1">
        <bytes:string rdf:datatype="http://nationalarchives.gov.uk/preservation/sigdev/signature/droidRegularExpression">255044462D312E34</bytes:string>
        <bytes:anchor>BOFoffset</bytes:anchor>
        <bytes:offset rdf:datatype="http://www.w3.org/2001/XMLSchema#integer">0</bytes:offset>
        <bytes:maxOffset rdf:datatype="http://www.w3.org/2001/XMLSchema#integer">0</bytes:maxOffset>
      </rdf:Description>
    </sigdev:byteSequence>
  </sigdev:DevelopmentSignature>
</rdf:RDF>

This can be used to generate a graph visualization of a signature, and provides another serialization of a DROID signature that could potentially be consumed by tools in the future.

User experiences

• Jenny Mitcham creates her first signature using the Signature Development Utility
• Andrea K. Byrne creates her first signature using the Signature Development Utility

Additional reading

• information about ffdev.info on openpreservation.org

Development activity

All development activity is visible on GitHub: https://github.com/exponential-decay/signature-development-utility/commits

Activity feed

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