If you are a tech nerd, you care about this.
If you just buy and use Micro$oft products and never think about it, you don’t care.
As of Windows 8, Microsoft is requiring that your hardware only work with their stuff. The boot loader locks you out otherwise. A couple of Linux distributions have signed up with Microsoft signing and paid fees (so Microsoft will let RedHat Linux boot, for example) but if you don’t like the idea of your machine talking to Micorsoft every time it boots up to get permission to run, you are screwed.
It’s the bios they are trying to control, the boot bios. The effects of Apple taking their Windows away is causing all sorts of strange reaction from Microsoft.
Apple is a UNIX derivative, specifically BSD. So at it’s core, Apple iOS is free. Apple holds the window system proprietary, as the open source rules say they can. It’s the underlying Darwin OS which is free.
UEFI You … Write new open source BIOS. Intel started this, way back when … in the mid 1990s.
The Unified Extensible Firmware Interface (UEFI) is a specification that defines a software interface between an operating system and platform firmware. UEFI is meant as a replacement for the BIOS firmware interface, present in all IBM PC compatible personal computers.
The original motivation for EFI came during early development of the first Intel–HP Itanium systems in the mid-1990s. PC BIOS limitations (16-bit processor mode, 1 MB addressable space, PC AT hardware dependencies, etc.) were seen as unacceptable for the larger server platforms Itanium was targeting. The effort to address these concerns was initially called Intel Boot Initiative, which began in 1998 and was later renamed EFI.
In July 2005 Intel ceased development of the EFI spec at version 1.10, and contributed it to the Unified EFI Forum, which has evolved the specification as the Unified Extensible Firmware Interface (UEFI). The original EFI spec remains owned by Intel, which exclusively provides licenses for EFI-based products, but the UEFI specification is owned by the Forum.
Version 2.1 of the UEFI (Unified Extensible Firmware Interface) specification was released on 7 January 2007. It added cryptography, network authentication and the User Interface Architecture (Human Interface Infrastructure in UEFI). The current UEFI specification, version 2.3.1, was approved in April 2011.
Happy booting, no Microsoft validation crap required.
If you are interested, more here — Shuttleworth: Why Windows 8 made us ditch GPL Linux loader