Page Tables: Memory Management in Computer Systems

This lecture discusses the organization and management of page tables in computer systems. It begins by defining page tables as data structures that store virtual-to-physical address translations, essential for the memory management unit (MMU) to translate addresses. Each process has its own page table, which is managed by the operating system and stored in memory. The lecture explains the structure of page table entries (PTEs), including various bits that indicate the validity and permissions of memory pages. It highlights the challenges of linear page tables, particularly their large memory requirements, and introduces multi-level page tables as a solution to these issues. The instructor illustrates how multi-level page tables reduce memory usage by only allocating space for the portions of the address space that are actually used. The lecture concludes with a discussion of the advantages and disadvantages of paging, emphasizing the importance of efficient memory management in modern computer systems.