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Your PC is a direct descendent of the IBM PC launched in 1981, when Microsoft’s windows still had glass in them. Of course, the specification has improved dramatically over three decades. Where early PCs had 64K or 128K of memory, for example, today’s usually have 4GB. Hard disks that started with a 10MB drive in the later IBM PC XT have grown to 500GB or more. The original IBM PC’s colour graphics adapter — which only displayed four colours (including black and white) in 320 x 200-pixel resolution — now looks like a bad joke.

Surprisingly, one part of the IBM PC has survived relatively unchanged for 30 years: the basic input/output system or BIOS chip. This is used to start up or boot the PC. Well, its days are numbered. With Windows 8, Microsoft is promoting the use of the Unified Extensible Firmware Interface (UEFI) instead.

Using UEFI should increase the PC’s security. Systems with BIOS chips are vulnerable to rootkit malware that takes control before the operating system starts. UEFI enables a validation process that provides for a “secure boot”. However, UEFI systems should also start up much faster, and can provide a graphical user interface that allows you to control your PC more easily than the BIOS chip’s primitive set-up routines.

It’s important to know that UEFI is not new, is not limited to Windows PCs, and is not controlled by Microsoft. UEFI — originally called EFI — is an industry standard that has been in use for a decade, and it’s now part of Windows 8′s pre-boot process.

Windows 8 will still run on PCs that have BIOS chips, which is almost all the PCs currently in use. PC manufacturers can still include a BIOS chip along with the UEFI code, which resides on the PC’s hard drive. On PCs with Intel or AMD processors, manufacturers can also allow users to disable secure boot or otherwise provide ways to load alternative operating systems. Those things are not under Microsoft’s control.

UEFI started life at Intel in 1998 when it became clear that the BIOS chip was not suitable for powerful servers, and when Intel wanted a system that was cross-platform, not designed specifically for the PC architecture. The original IBI (Intel Boot Initiative) was later renamed EFI (Extensible Firmware Interface), then Intel gave it to an independent industry body. The non-profit Unified EFI Forum now steers UEFI’s development by the community.

A decade ago, Intel and HP started using EFI on workstations and servers with Itanium chips. Later, it was used by other server suppliers such as Dell and IBM. However, Apple was the first big adopter, using EFI when it switched to Intel processors in 2006.

Microsoft started supporting UEFI with Windows Vista SP1 and Windows Server 2008, so 64-bit versions of Windows 7 are already UEFI-compatible. Relatively few PC manufacturers shipped UEFI, but adoption started to grow with the arrival of Sandy Bridge (Intel Core iX) chips early in 2011. If you have, for example, an Asus P67 motherboard, you have UEFI support already.

So why has Microsoft finally started to push UEFI, so many years after Apple? I think there are three main reasons:

  • Microsoft needs to support Windows on a different processor architecture: ARM. (See Windows for ARM chips leaves Intel behind.)
  • It wants Windows to be as secure as possible, and “secure boot” is a popular approach on other devices such as tablets.
  • Microsoft wants users to benefit from new features such as faster startup times and increased ease of use.

Of course, it will take a long time to switch to UEFI, so Microsoft will have to support both systems for a while. Some of today’s billion PC owners will want to move to Windows 8 or 9, and Microsoft will want to sell them upgrades. Also, some businesses will want to buy new PCs to run older versions of Windows.

The PC world will change gradually as more new UEFI PCs are sold and older machines are scrapped. But I suspect it will be many years before BIOS chips disappear altogether.



Asus has some UEFI pics, eg

or scroll down at

ASUS Sandy Bridge UEFI Preview

From Anandtech

features #24419 | 342
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