AMIBIOS 6

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The POST screen used by early AMIBIOS 6, although some slight changes have occurred over years

AMIBIOS 6 is a family of various revisions of AMIBIOS developed by American Megatrends between 1995 and 2001. These revisions are mostly known with the date 071595 (July 15, 1995) in the ROM identification string (at the bottom of the screen), however some newer revisions also use other dates such as 071599 (July 15, 1999).

It was mainstream for a very long time. It was the flagship AMIBIOS version from July 1995 until 1999 when the earliest known revisions of AMIBIOS 07.00.xx were released, and even after then was still widely used by most manufacturers until 2001 when AMIBIOS 07.00.10 was released.

Early revisions of AMIBIOS 6 still could only utilize storage devices in up to 32 GB capacity, however in the late-90s this limit was increased to 64 GB. It is also the first version of AMIBIOS to natively support PnP (Plug and Play), a hardware detection technology standardized with Microsoft Windows 95. Although some later revisions of AMIBIOS 5 were also bundled with add-on ROMs for PnP support.

POST screen

As AMIBIOS 6 was in use for a very long time, various changes to the POST screen were made over time. The EPA (Energy Star certification logo) can also change depending on OEM customizations and the revision.

Setup Utility

Unlike earlier versions of AMIBIOS, AMIBIOS 6 supported a variety of pre-built setup utilities for use by OEMs. Early revisions only offered the WinBIOS (resembling the AMI WinBIOS and AMIBIOS 5 setup) or the Hi-Flex (resembling the AMI Hi-Flex BIOS setup) setup utilities, while Easy Setup (resembling the Intel AMI Hi-Flex fork setup) and Simple Setup (resembling the Award EliteBIOS setup) were also introduced later (the former in 1997 and the latter in 1998).

In addition to the pre-built setup utilities from AMI, AMIBIOS 6 also supported custom utilities that could be created by the OEM. Technical details (IDE, programming language, API, etc.) regarding these custom utilities are currently unknown, but a few OEMs such as Intel and Gateway 2000/ALR used AMIBIOS 6 with a custom setup utility.

Bugs and quirks

NOTE: The following issues may not represent every instance of AMIBIOS 6 and may vary depending on the OEM's implementation and the revision.

People have reported Plug and Play related problems on early AMIBIOS versions with Plug and Play support (presumably AMIBIOS 6). However the problems were later said to have been fixed around 1997.[1]

Early versions of AMIBIOS 6 also have a bug in their El Torito (CD boot) implementation where Windows NT 5.x (Windows 2000, XP etc.) disks may not be bootable. Attempting to boot such a disk on these versions will likely result in an NTLDR is missing error, regardless of the used disk.

Thomas Pabst of Tom's Hardware has also reported IRQ routing problems with AMIBIOS 6 (erroneously called "AMI WinBIOS" due to confusion caused by the setup utility's name) on various Intel 440BX chipset motherboards with it, calling it "a big disappointment".[2]

Intel fork

The POST screen used by Intel's AMIBIOS 6 fork, in 640x480 with 8x19 font

Main page: List of BIOS and UEFI firmware used by Intel motherboards

Intel forked the AMIBIOS 6 source code (ROM identification date 071595) around 1998 and started using it on their motherboards. This fork was sometimes seen with the unusual revision number 063200 (the last for standard AMIBIOS 6 was 063100). This fork was later replaced by an AMIBIOS 8 fork around 2003.