NOTE that this page dates from around the DROID 5 release. There's some useful info, but needs updating.

Droid and Pronom

Many of us have used Droid or Pronom in our work. This page includes some ideas and resources that may be of use to understand them better - or even make better use of them.

• Service to retrieve the current signature file: http://www.nationalarchives.gov.uk/pronom/service.asmx
• When you run Droid, it will place a copy of the current signature file in ~/.droid/signature-files
• The signature file contains information on all of the formats that Pronom knows. The signatures, however, have been compiled into a format that makes it easy to apply, but hard to understand. The following script will fetch the full XML documents for each format and place them in a subdirectory called xml.

The result of executing this Bash script is attached below.

Thoughts

• Droid 5 is much faster than its predecessor, but it appears to slow down with each file it scans. After a couple of thousand, it can get quite slow. I believe that this is because the GUI does not scale well.
• Droid 5 has a command-line mode, but unfortunately, the implementation intertwines the GUI with the command-line tool. As a result, the command-line version is slow to start and exit. This can be OK when using it to process a large number of files, but it means that it can't be used as part of a script or automated process.
• The core routine to match a file against a signature appears to be unchanged from Droid 4.
• It should almost be easy to implement an efficient command-line matcher.
• There has been a lot of effort put into developing the GUI and less into developing the signatures. Pronom lists over 700 file formats, but has signatures for only 245 of them.