Museum Digital File Preservation: File Integrity

Digital preservation is an area often overlooked when developing a museum digital program. Admittedly, it is the most ambiguous area of digital work because it’s predicated on “it depends” scenarios and ever-changing technology that results in obsolescence. 

As discussed in Myth #4: Digital = Permanent in the series 5 Digitization Myths to Delete Forever (via Lucidea’s Think Clearly Blog), I explain that digital preservation is about two things: 

1. Digital file integrity; and 
2. Digital file access.

In this first post, we’ll focus on digital file integrity and how the museum can help to ensure museum digital files are as healthy and whole as possible. 

Digital File Integrity

Digital file integrity is about the integrity of the file. As time goes on and as files are opened and moved, digital files can slowly begin to lose bits of itself. This is known as losing file integrity. Digital preservation is primarily about the practice of maintaining file integrity.

Creating a Preservation Copy

If the integrity of a file can be altered (intentional or not) every time it’s opened, how do we help to ensure its integrity? The most fool-proof way is to ensure there’s a secondary copy so that two versions of the file exist: a working copy, and a preservation copy. A preservation copy should be made as soon as the museum creates the file or the file comes into the museum’s possession. The preservation copy should be stored with other preservation files in a designated storage location. The working copy is what remains easier to access for all work and reference needs.

Safeguarding Integrity

Unfortunately, it’s not enough to make a preservation copy and store it separately. It’s still possible for digital files to atrophy with age. This is where checking a digital file’s health on a regular schedule can help to safeguard against loss of file integrity. Platforms that were created with digital preservation principles in mind have these integrity-check mechanisms built in (e.g. checksum comparisons). But most museum Collections Management System (CMS) platforms are still lacking a comprehensive digital preservation module. Until there’s better options in the market, I recommend exploring Library of Congress’ Bagger version of Bag It (free, open-source), and AVP’s Fixity Pro tool (low-cost, annual fee).

A Basic Digital File Integrity Workflow

The following is an example of what a basic digital file integrity workflow can look like:

1. A newly digitized collection or born digital collections arrives.
2. A copy is made of all the files with a set of files identified as a preservation copy, and the other labeled for access and regular use.
3. The preservation copies are removed to a separate storage location, preferably one that is offsite and/or facilitates regular offsite backups.
4. If Fixity Pro or another tool is available to run scheduled integrity checks, update the tool to capture the new preservation file set. 
5. If no scheduling tool exists to run integrity checks then place all of the preservation files into Bagger and generate the integrity data that can be checked against those files at a later date.

Digital Preservation Learning Resources

The best place to begin is to become familiar with the resources available. Preserving (Digital) Objects with Restricted Resources (POWRR) offers introductory resources on what components make up a digital preservation strategy, webinars and a list of tools to use to help safe-guard digital files. Community Owned Preservation Tools Registry (COPTR) provides an updated listed of tools (informed by POWRR) and is a wiki currently active in documenting the group’s digital preservation work, workflows, and tools.

Conclusion

Now that we have the basics in mind for preserving digital file integrity, next week we’ll tackle how to maintain digital file access—the second piece of the digital preservation puzzle.