[gmcharlt]

Fun fact: the MARC format, used for bibliographic metadata by the majority of libraries that have digital catalogs, included supporting the printing of catalog cards as one of its use cases [1]. To this day a properly maintained library catalog based on MARC could, with some effort, be used to generate an equivalent set of printed catalog cards.

However, printed catalog cards as a backup to the digital catalog have practical problems. For one thing, they are heavy. A full card catalog of a large public library could easily weigh tons [2] and take up space that would be better used for other functions. For another thing, the expense would detract from other library services, and many libraries already suffer from budgetary challenges.

A proper backup strategy is the way with the risk of losing the digital catalog. Besides, libraries have more fundamental problems to deal with regarding the permanence of electronic resources. For example, the fact that libraries largely do not and cannot _own_ the ebooks they circulate causes numerous problems.

[1] https://www.allpurposeguru.com/2021/03/henriette-avram-and-t... [2] https://blogs.loc.gov/preservation/2022/10/moving-card-catal...