User:Historybuff/UEFI

UEFI.

Originally started as EFI by Intel, it grew into a consortium that now supports the standard.

The intention of this is to overcome the limited way the original PC BIOS booted; which was to use a "master boot record" (MBR) on the first disk sector (first removeable/floppy disks, and then later hard disks) to launch an operating system. This worked fine for small and lightweight operating systems, like early MS-DOS; but by the time Windows started to evolve as a distinct OS, the extremely small space allocated for the boot binary were not big enough, and the MBR became part of a loading chain to get the Operating System Kernel booted. As systems evolved from 8 bit to 16 bit to 32 bit Operating Systems, it was clear how limited this scheme was, and how cumbersome it was to go from Power on until Full boot. There were also problems with non-traditional boot methods (such as Network or USB device booting).

UEFI was intended to address many of the shortcomings. UEFI identifies possible boot candidates; if the boot candidate is a disk, it looks for a special UEFI partition, with a FAT format and a particular hierarchy to know what bootloader to run.