File Formats – ross spencer :: exponentialdecay [-dot-] co [-dot-] uk

Cat's Meow from the Offner Dynograph EEG

What will you bitflip today?

I want to let you into a secret: I enjoy corruption. Corrupting digital objects leads to undefined behavior (C++’s definition is fun). And flipping bits in objects can tell us something both about the fragility, and robustness of our digital files and the applications that work with them.

I had a pull-request for bitflip accepted the other day. Bitflip is by Antoine Grondin and is a simple utility for flipping bits in digital files. I wrote in my COPTR entry for it that it reminds me of shotGun by Manfred Thaller. The utility is exceptionally easy to use (and of course update and maintain written in Golang) and has some nice features for flipping individual bits or a uniform percentage of bits across a digital file.

My pull-request was a simple one updating Goreleaser and its GitHub workflow to provide binaries for Windows and FreeBSD. I only needed to use Windows for a short amount of time thankfully, but it’s an environment I believe is prevalent for a lot of digital preservationists in corporate IT environments.

Bitflip is a useful utility to improve your testing of digital preservation systems, or simply for outreach, but let’s have a quick look at it in action.

Tyler's Halloween Matryoshka Dolls represent the internal complexities of container file formats. The dolls here have formats attached to them representing different ways they might be nested, with ZIP and OLE2 being the primary containers that can be handled in DROID and Siegfried at present.

A year in file formats 2024

A great write up from Francesca at TNA about the past year for PRONOM via Georgia at the OPF.

It’s great to see the continuing work including vital translation of guides into other languages. Francesca includes a couple of shout outs to some pieces I have contributed in my spare time this year; including a collaborative workshop with Francesca, David, and Tyler at iPRES2024.

Silver birth tree in Ravensburg featuring its characteristic eye-like bark.

Code as memory?

It is very poetic to think about code as it containing the memory of its maintainers. I don’t entirely disagree with the idea, but it’s overly poetic and the reality of maintenance on systems that have become too unwieldy is anything but poetic.

C3PO narrates the story of Star Wars to the Ewoks in Return of the Jedi

PRONOM’s dustiest records

Tyler’s recent blog post for the PRONOM Hack-a-thon Week 2024 (my previous for this week), brought up an interesting point about two of PRONOM’s oldest outline records, Real Video Clip (fmt/204) and Real Video (x-fmt/277). How did they end up in PRONOM?

NB. because of the complexity of this post, it may be easier to read in original blog form, than on Mastodon here: https://exponentialdecay.co.uk/blog/pronoms-dustiest-records/

Tyler suggests:

I assume PRONOM originally added these based on MIME types available.

I thought I knew the answer, but it prompted a forensic look at the records to see if what I thought I knew aligned with reality!

Lovebot by Matthew Del Degan. Taken in Toronto in 2017.

simpledroid: completing the circle

It’s nearing the end of 2024 and that must mean a PRONOM hackathon as part of the World Digital Preservation Day (#WDPD2024).

My contribution is a follow-up on my work earlier in the year to produce a valid DROID signature file from Wikidata in wddroidy.

Making DROID work with Wikidata

Wikidata is a good service, Wikibase (on which Wikidata is built) is a better platform.

I have spoken before about its potential to be added into the file-format registry ecosystem in a federated model.

If we are to use it as a registry that can perhaps complement the pipelines going into PRONOM, e.g. in vendor’s digital preservation platforms such as the Rosetta Format Library, a Wikidata should be able to output different serializations of signature file for tools such as Siegfried, DROID or FIDO.