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 […]
By Jay Gattuso, posted in Jay Gattuso's Blog
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 […]
By Jay Gattuso, posted in Jay Gattuso's Blog
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, […]
By Jay Gattuso, posted in Jay Gattuso's Blog
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!
By Jay Gattuso, posted in Jay Gattuso's Blog
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 […]
By Jay Gattuso, posted in Jay Gattuso's Blog
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 […]
By Jay Gattuso, posted in Jay Gattuso's Blog
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 […]
By Jay Gattuso, posted in Jay Gattuso's Blog
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 […]
By Jay Gattuso, posted in Jay Gattuso's Blog