Binary search trees have deep heights (O(log2 N)), meaning every lookup requires 15-20 disk I/O operations. B+ Trees have a high fan-out (each node holds hundreds of keys), keeping tree height at 3-4 even for millions of records. Plus, all leaf nodes are linked in a doubly linked list, making range queries (`WHERE age BETWEEN 20 AND 30`) blistering fast.

When a process references memory, the CPU's MMU uses page tables to translate the virtual address to a physical RAM frame. If the present bit is 0, the CPU triggers a page fault interrupt. The OS pauses the thread, fetches the 4KB block from swap disk into RAM, updates the page table, and resumes the instruction. That is why excessive swapping grinds your computer to a halt.