What are Physical Address Extension ( PAE ) and Preboot eXecution Environment ( PXE ) ?

Physical Address Extension (PAE) is a feature to allow32-bit IA-32 central processing units (CPUs) to access a physical address space (including random access memory and memory mapped devices) larger than4 gigabytes.

The Preboot eXecution Environment (PXE) is an environment to boot computers using a network interface independently of data storage devices (like hard disks) or installed operating systems.