Libraries have been modernizing their internal structure for thousands of years. Written works were once scarce enough that a single librarian could know of and catalog all of them; as of 2010, there were almost 130 million unique written works in the world. To cope with this, library science created first the Dewey Decimal System, then the card catalog, and then incorporated microfilm and microfiche. As the digital age progressed, cataloging books became easier, smaller, and faster.
When introducing a new electronic innovation to a library, overseers must take care to both properly train staff and make them aware of redundancies in the systems. For example, a computer database of all the books with their Dewey numbers makes the card catalog obsolete; however, there might be unique information on the cards that is not automatically generated by software. Additionally, as new versions of software and hardware become available, older equipment or files might not be compatible, and would need to be discarded or reentered by hand.
Another problem is the dependency of electronic resources on electricity. While the card catalog is obsolete and inefficient, it works when the power goes out; a large library with a constantly updating information system might need a backup generator to keep their servers online. A bound print copy of Dewey numbers -- smaller than the card catalog -- and staff trained to use it would also be useful.
The most important feature of a library is the ability to find information; by understanding older systems, newer technology can be made more efficient.