Productivity site 43 Folders has turned up a 2005 article from MIT's Technology Review on two of the most elemental innovations in office technology: the tab (as in a tabbed folder) and the index card.
In Keeping Tabs, Ed Tenner delivers some excellent trivia:
...In 1876, Melvil Dewey, inventor of decimal classification, helped organize a company called the Library Bureau, which sold both cards and wooden cases. An academic entrepreneur, Dewey was a perfectionist supplier. His cards were made to last, made from linen recycled from the shirt factories of Troy, NY. His card cabinets were so sturdy that I have found at least one set still in use, in excellent order. Dewey also standardized the dimension of the catalogue card, at three inches by five inches, or rather 75 millimeters by 125 millimeters. (He was a tireless advocate of the metric system.) Even the Library Bureau did not offer a convenient way to separate groups of cards, apart from thin metal partitions that wrapped around them, or taller cards. The tab was the idea of a young man named James Newton Gunn (1867"“1927), who started using file cards to achieve savings in cost accounting while working for a manufacturer of portable forges. After further experience as a railroad cashier, Gunn developed a new way to access the contents of a set of index cards, separating them with other cards distinguished by projections marked with letters of the alphabet, dates, or other information. ... The Library Bureau also produced some of the first modern filing cabinets, proudly exhibiting them at the World's Columbian Exposition in Chicago in 1893. Files had once been stored horizontally on shelves. Now they could be organized with file folders for better visibility and quicker access. Tabs were as useful for separating papers as for organizing cards. Since business people were unfamiliar with the new technology, Library Bureau staff provided consulting services as well as equipment and supplies.
Read the rest for a nice overview of index card and tab technology. (And when was the last time you thought of either of those as technologies?)
(Photo courtesy of Lars Aronsson, under a Creative Commons ShareAlike 1.0 License.)