And it’s built in dimensional analysis.
Gee, how long will take my OPAC indexer to index 3 million odd records at 53 records per second?
I got an answer in hours, which means I did it right. If I accidentally guessed multiplication instead of division there, I’d get an answer in megahertz, and that would be a good clue that I didn’t do it right. :)
Bibliographic Wilderness 
What is significant about this (Google Calculator, etc.) is that it provides answers to questions, unlike many library-related applications which (merely) provide pointers to answers. Library “catalogs” could provide answers if we (librarians) were to design them to do so. –ELM
Eric, what’s your vision of a catlaog that provides answers? What I’m imagining is a very challeninging task that would take more than just deciding to try in order to succeed!
Our OPAC used to know the answer to the ultimate question of life, the universe and everything ;-D
http://www.daveyp.com/blog/archives/77
…sadly, it looks like it’s forgotten the answer now (I’ll have to check to see why the code isn’t working)