AMIBIOS 6

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

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

It was mainstream for a very long time. It was the newest AMIBIOS core version from July 1995 up until 1999 when the earliest known instances of AMIBIOS 07.00.xx were released, although it was still widely used by most manufacturers until April 2001 when it was finally replaced by AMIBIOS 07.00.10.

Early versions of AMIBIOS 6 still could only detect up to 32 GB hard drives, however in around 1999 this limit was increased to 64 GB. AMIBIOS 6 was also the first version of AMIBIOS to natively include built-in PnP (Plug and Play) support, a hardware detection technology standardized with Microsoft Windows 95. Although some later instances of AMIBIOS 5 also had add-on ROMs for PnP support.

POST screen

As AMIBIOS 6 was in use for a very long time, changes to the POST screen (along with other parts of the BIOS) were made over time. The EPA (Energy Star certification logo) can also change depending on the preference of OEMs and the core version.

Setup Utility

Unlike AMI WinBIOS and AMIBIOS 5, AMIBIOS 6 included a variety of setup utilities for use by OEMs. Early versions only offered the WinBIOS (resembling the AMIBIOS 4 and 5 setup) and 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, former in 1997 and latter in 1998.

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 core version.

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

Early versions of AMIBIOS 6 also have a bug with 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 used disc.

Thomas Pabst of Tom's Hardware has also reported issues regarding IRQ routing with AMIBIOS 6 (mistakenly referred to as "AMI WinBIOS" due to used setup utility) 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 firmwares used by Intel motherboards

Intel forked AMIBIOS 6 subcore date 071595 in around 1998 and began using it on their motherboards. This fork sometimes also used an unusual 063200 core number (last for regular AMIBIOS 6 was 063100). It was later replaced with the AMIBIOS 8 fork in around 2003.