A librarian wants to scan the titles of the latest books in the marketing section. These books are quite heavy and stacked in a drawer. Which device will the librarian use and how

A PC (RDBMS must be installed). Its an Index in fact, through which this can be done. You should also know that each shelf does list out the least index and maximum index it has.

Explanation:

Suppose you are acquainted with the color/size of the book, and the book is kept somewhere on some shelf. You cannot ever find them from your chair. You need to move from one shelf to the other. However, if you have the knowledge of the index, you can move through the shelf through your computer, and find the exact location of the book on the shelf. Hence, its the PC, and one that has an RDBMS software that implements an indexer. You must know the index number hence for deciphering the book, and nothing else.