Mastodawn

Revisiting bsdiff as a tool for digital preservation

I introduced bsdiff in a blog in 2014. bsdiff compares the differences between two files, e.g. broken_file_a and corrected_file_b and creates a patch that can be applied to broken_file_a to generate a byte-for-byte match for corrected_file_b.

On the face of it, in an archive, we probably only care about corrected_file_2 and so why would we care about a technology that patches a broken file?

In all of the use-cases we can imagine the primary reasons are cost savings and removing redundancy in file storage or transmission of digital information. In one very special case we can record the difference between broken_file_a and corrected_file_b and give users a totally objective method of recreating corrected_file_b from broken_file_a providing 100% verifiable proof of the migration pathway taken between the two files.

Continue reading “Revisiting bsdiff as a tool for digital preservation”…

#ac3 #archives #audio #audiovisual #audit #authenticity #av #bash #bsdiff #checksums #code4lib #corruption #corruptionIndex #digipres #digitalArchiving #digitalForensics #digitalLiteracy #digitalPreservation #digitalStorage #diplomatics #fileFormats #glitch #glitchAudio #glitchart #integrity #preservationAnalysis #preservationMetadata #provenance #sensitivityIndex #storage

Ross Spencer Feb 11, 2025

The sensitivity index: Corrupting Y2K

by @beet_keeper

In December I asked “What will you bitflip today?” Not long after, Johan’s (@bitsgalore) Digtial Dark Age Crew released its long lost hidden single Y2K — well, I couldn’t resist corrupting it.

Fixity is an interesting property enabled by digital technologies. Checksums allow us to demonstrate mathematically that a file has not been changed. An often cited definition of fixity is:

Fixity, in the preservation sense, means the assurance that a digital file has remained unchanged, i.e. fixed — Bailey (2014)

It’s very much linked to the concept of integrity. A UNESCO definition of which:

The state of being whole, uncorrupted and free of unauthorized and undocumented changes.

Integrity is massively important at this time in history. It gives us the guarantees we need that digital objects we work with aren’t harboring their own sinister secrets in the form of malware and other potentially damaging payloads.

These values are contingent on bit-level preservation, the field of digital preservation largely assumes this; that we will be able to look after our content without losing information. As feasible as this may be these days, what happens if we lose some information? Where does authenticity come into play?

Through corrupting Y2K, I took time to reflect on integrity versus authenticity, as well as create some interesting glitched outputs. I also uncovered what may be the first audio that reveals what the Millennium Bug itself may have sounded like! Keen to hear it? Read on to find out more.

Continue reading “The sensitivity index: Corrupting Y2K”…

#ac3 #archives #audio #audiovisual #authenticity #av #bash #checksums #code4lib #corruption #corruptionIndex #digipres #digitalArchiving #digitalLiteracy #digitalPreservation #diplomatics #fileFormats #flac #glitch #glitchart #glitchaudio #integrity #mp3 #sensitivityIndex #wav