Zero-Fill on Demand - All new pages map to a single zero "frame" in physical memory. In this case, you don't get any memory until you write to the page, at whic

Zero-Fill on Demand - All new pages map to a single zero "frame" in physical memory. In this case, you don't get any memory until you write to the page, at which time the OS steps in and allocates you a page of all zeros EDIT: this means if the kernel can't allocate more memory when you write then the kernel has a decision to make; kill you, or kill someone else to get more memory.