At that time, there were several card cabinets in the lending room of the library, just like a Chinese medicine shop. There is a book card in each small drawer, and each card has information about a book. Sort all the books and cards by title and put them in the drawer. This cabinet is the title search cabinet. If sorted by author's name, it is the author's name retrieval cabinet. There is also sorting by book classification, which is the classified retrieval cabinet. A library must have at least these three retrieval tools.
The cards in each drawer are vertical, and there is a round hole under the card. An iron bar passes through the round hole to string the cards together, so that readers will not lose the cards when browsing, and it is convenient to add cards at a certain position.
For example, if you want to borrow a dream of red mansions, you can find the drawers with the word "red" in the pinyin order in the title search cabinet, find the dream of red mansions in order, and then copy the title and book number on a small piece of paper.