Jay Gattuso's Blog

Technical provenance metadata is metadata that details technical changes that have been to a file during its life. Note that this does not detail changes made across versions of a file, but to the file itself. Within the National Library of New Zealand systems environment, we have no single natural home for technical provenance information […]

If you are, what are you retaining and why? If not, why not? There is more to come from us on this topic – but for now I'd love hear any opinions / thoughts. And what do I mean by technical provenance? Good question. I mean any filename sanitation, or QA changes to (meta)data, or […]

Following a few interesting conversations recently, I got interested in the idea of 'bit flip' – an occasion where a single binary bit changes state from a 0 to a 1 or from a 1 to a 0 inside a file. I wrote a very inefficient script that sequentially flipped every bit in jpeg file, […]

I have attached a basic introduction to writing format signatures – this written to assist new colleagues, or anyone new to the idea of writing basic signatures for the PRONOM /use with DROID.   I hope that you find it useful, and if I’ve made any blunders please let me know!

Following on from the interesting discussion in my last post about the jpeg signatures, I undertook some quick testing on the impact of using / not using the EOF sections of a DROID signature file. I previously posted this signature file here: http://dl.dropbox.com/u/59534857/DROID_SignatureFile_V55%20-%20no%20EOF.xml    I have compiled my results and written a brief paper that is […]

In a relatively recent signature update, the fmt/44 signature was updated to in allow some data after the stated EOF marker (ff d9). In the case that started this off, a number of fmt/44 jpg files were found that had a couple of bytes after what DROID looks for as an absolute EOF. I had […]

I wonder if many people have had a chance to dig around in the latest signature release for DROID? There is an interesting format change that I think warrants some discussion. As I understand it, historically tif has been a problem for DROID based ID. Pronom has records for TIFF versions 3, 4, 5, and […]

I would like to pose a scenario for your comment: Description  A large set of files, ~5,000. Created between ~1993 to ~1997 Creation software unknown Given extension .ASC PRONOM PUIDs: x-fmt/22 (7-bit ASCII Text) and x-fmt/283 (8-bit ASCII Text) relate DROID matches by extension as above JHove: ASCII-hul (Status: Well-Formed and valid) Visual inspection confirms […]