This document discusses different data structures and their classifications. It defines data structures as ways of organizing data that consider both the stored elements and their relationships. Data structures can be linear (processed sequentially like arrays and linked lists) or non-linear (where insertion and deletion cannot be done linearly, like trees and graphs). Data structures are also classified as primitive (basic types operated on by machines) and non-primitive (more complex structures derived from primitive ones, like arrays, lists and files). Common operations on data structures include traversing, searching, inserting and deleting.