This lecture covers the concept of page-based virtual memory in computer systems. It begins with a review of segmentation and its limitations, particularly external fragmentation and complexity in sharing memory. The instructor introduces paging as a solution, explaining how it divides the address space into fixed-size pages and manages physical memory in frames. Key benefits of paging over segmentation are discussed, including improved efficiency and the elimination of the need for contiguous physical memory allocation. The lecture details the structure of virtual addresses, which consist of a virtual page number and a page offset, and explains how the memory management unit (MMU) translates virtual addresses to physical addresses. Examples illustrate how virtual pages map to physical frames and how to access memory locations using paging. The lecture concludes with a discussion on the management of page tables and the implications of using page-based virtual memory for efficient memory access and protection.