Rethinking Fixity in the Midst of its Costs

Crystal Sanchez
Electronic Media Review, Volume Eight: 2023-2024


Fixity is the preservation action of ensuring that a digital file has not changed by checking that all the bits are intact: that it is fixed. In the digital preservation field, we do this by creating and validating checksums at different points in the lifecycle of a digital file. For artwork components that are in digital form, this is a recommended action in preventative care, and at any time an action is applied to that component. Checksums are digital fingerprints for a file, algorithms that are run on the bits of a file to output a unique hash code that can be validated later on. Running checksums is processor-, storage-, time-, and human-intensive, and we do not often discuss the cost of this to both ourselves and our environment. Also, does anyone run and validate checksums as often as recommended? Why do we recommend this as a regular practice when so many other actions we take also ensure the fixity of the file? This talk will discuss fixity as recommended; some tools, alternate modes of ‘fixity’ for digital collection holders; and whether and when any are appropriate. Scaled examples from the Smithsonian Digital Asset Management will be used to provide some context and history of implementing and choosing fixity paths, from building tools in 2014 to help users validate checksums on upload; tiered annual checksum validation for select assets starting in 2015; and running checksums and validating fixity for the first time on over 30 million assets in 2021-22.