We just finished the third module in the Intro to Digital Curation class that I’m teaching this semester. The first module was mostly us getting our bearings, and the second was learning about how confusing the term digital object is, and getting acquainted with interacting with the file system.
The overarching goal of the class is to start with seeming simple ideas like digital objects, and files and keep zooming out until the last module where we talk about infrastructure. This may prove to be a bad idea, but so far it seems to be working ok. Each module is two weeks where we alternate between reading and discussion (in Canvas) and reading and coding (in Jupyter notebooks).
In Module 3 we discussed and experimented with file formats and standards. We talked about Chapter 3 in Trevor Owens’ Theory and Craft of Digital Preservation where he lays out some examples of the artifactual qualities of digital objects, that center on the properties of several types of files, and their use. I asked students to identify the formats at play, and I was surprised and intruiged by the confusion between file formats and other computational objects. For example some thought that a game was a format. I mean, I guess they often are. But a game itself is abstract a concept to be a file format.
Maybe the game is made up of some Python source code files (as in Owens’ Civilization example). Or perhaps the script to Rent is made up of Word files. Or in the case of the Mystery_House game a specific disk imaging format was used to store a representation of a physical disk. Some students confused the file format and the medium it was stored on (a zip disk, a CD or a floppy disk).
Perhaps this confusion arose from my pairing of the Owens reading with Andrew Russell and Lee Vinsel’s short NYTimes piece The Joy of Standards. I wanted students to think about the relationship of file formats and standards. But standards swarm in devices like storage media and computational devices. I didn’t do a great job of distinguishing between file formats, storage and standards, and showing how they were interrelated. That being said, more than half the students were able to communicate the difference–so it wasn’t a total wash.
In the Jupyter notebook exercise we explored file format identification through three different methods:
- looking at file extensions
- using the libmagic via the python-magic library
- using the PRONOM registry via the fido tool
Since running fido wasn’t exactly trivial in a Jupyter notebook (it’s really designed to be run from the command line) I created a small pip installable utility called puid which give you one function
get_puid() which made it much easier to give to students to use. Maybe it could be useful in other contexts:
The notebook provides some examples of how to programmatically iterate through files and apply each method for file format identification. Then it asks them to do some file format checking of unique dataset of files that I created for each student that was sampled from the Govdocs1 dataset on Digital Corpora. The interesting part came when they were asked to compare the results, and try to explain why there might be differences.
Several students honed right in on the fact that python-magic and fido represented different ways of classifying formats. The granularities were often different, and the identifiers they used were different as well. Some even highlighted the processes by which these tools are maintained which was very interesting to see.
All in all I think it was a successful exercise, because students started thinking about how different tools generate different truth values, and that it’s important to think critically about the tools we use, especially in digital curation practices. Tools themselves are part of particular computational practices, and not law etched in stone. Simple things like file format identifiers have fuzzy edges that can be hard to define. But identifying them is super important for rendering them as digital objects.
Next up we’re looking at internal metadata which I’ll try to write about here when we get to it. I would like to bundle up these notebooks in a useful way at the end of the semester if these exercises look useful to others. I’ve really been enjoying using Colab so far. Thanks Nick for the recommendation!