The document discusses the pagefile.sys, hiberfil.sys, and swapfile.sys files in Windows 8. It explains that pagefile.sys is used for virtual memory when physical RAM is exhausted. Hiberfil.sys is used for hibernation and fast startup, and only exists if fast startup is enabled. Swapfile.sys is used specifically for suspending and resuming Metro apps, and may have other future uses. It is smaller than pagefile.sys.