What is meant by virtual memory? virtual memory is a memory management technique that provides an "idealized abstraction of the storage resources that are actually available on a given machine" which "creates the illusion to users of a very large (main) memory". Time complexity of insertion in Linked List vs. Array? Linked list: O(1) Array: O(n) Memory storage - heap vs stack? Stack: linear data structure, high-speed access, no fragmentation, local variables only, variables can't be resized. Heap: hierarchical data structure, slow access time(compared to stack), memory can become fragmented, global variables, variables can be resized.