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AMIBIOS is a personal computer BIOS developed by [[American Megatrends|AMI (American Megatrends)]]. It was released in 1985 by Access Methods Inc. as one of the earliest fully and legally IBM PC-compatible solutions for the system's clones. As the IBM PC's BIOS was copyrighted and early implementations based on its documentation suffered from legal trouble, companies like [[Phoenix Technologies|Phoenix]] and Access Methods reverse engineered their own solutions under a clean room design to avoid such trouble, with AMIBIOS being the latter's solution (shortly released after the former's [[PhoenixBIOS]]). It was then acquired by American Megatrends Inc. next year.
AMIBIOS is a personal computer BIOS developed by [[American Megatrends|AMI (American Megatrends)]]. It was released in 1985 by Access Methods Inc. as one of the earliest fully and legally IBM PC-compatible BIOS for its clones. As the IBM PC's BIOS was copyrighted and early implementations based on its documentation suffered from legal trouble, companies like [[Phoenix Technologies|Phoenix]] and Access Methods reverse engineered their own solutions under a clean room design to avoid such trouble, with AMIBIOS being the latter's solution (shortly released after the former's [[PhoenixBIOS]]). It was then acquired by American Megatrends Inc. next year.


While it is still used on some legacy platforms (such as the ones using the Vortex86 SoC), it was phased out on most consumer platforms in the early 2010s in favor of UEFI solutions such as [[AMI Aptio|Aptio]] (developed by the same company), [[InsydeH2O|InsydeH2O,]] and [[Phoenix SecureCore]]. Although earlier instances of Aptio contained an embedded version of [[AMIBIOS 8]] as a component module for legacy boot (CSM). However, since CSM was discontinued by Intel in 2020, the module is no longer present.<ref>https://www.intel.com/content/www/us/en/content-details/630266/removal-of-legacy-boot-support-for-intel-platforms-technical-advisory.html | Note: Although this document was published in 2023, it clearly mentions legacy boot being discontinued in 2020.</ref>
While it is still used on some legacy computer systems (such as the ones based on [https://en.m.wikipedia.org/wiki/Vortex86 the Vortex86 SoC]), it was phased out on most consumer platforms in the early 2010s in favor of UEFI firmware such as [[AMI Aptio|Aptio]] (also by AMI), [[InsydeH2O|InsydeH2O,]] and [[Phoenix SecureCore]]. Although earlier instances of Aptio contained an embedded version of [[AMIBIOS 8]] as a component module for legacy boot (CSM). However, since CSM was discontinued by Intel in 2020, the module is no longer present.<ref>https://www.intel.com/content/www/us/en/content-details/630266/removal-of-legacy-boot-support-for-intel-platforms-technical-advisory.html | Note: Although this document was published in 2023, it clearly mentions legacy boot being discontinued in 2020.</ref>


== Acquisition from Access Methods Inc. ==
== Acquisition from Access Methods Inc. ==
''Main page: [[American Megatrends]]''
''Main page: [[American Megatrends]]''


Access Methods Inc., a joint venture founded by Subromanian Shankar and Pat Sarma, released AMIBIOS in 1985.<ref>https://twit.tv/shows/triangulation/episodes/226</ref> The same year, the owners found a new company with the funds raised by this joint venture. It was called Quintessential Consultants Inc. (QCI), which then got renamed to American Megatrends Inc. (AMI) to keep the "AMIBIOS" acronym. The new company then acquired AMIBIOS from Access Methods in 1986.<ref>https://www.youtube.com/watch?v=5jYX3sL08Xs</ref>
Access Methods Inc., a joint venture by Subromanian Shankar and Pat Sarma, released the first version of AMIBIOS in 1985.<ref>https://twit.tv/shows/triangulation/episodes/226</ref> Due to legal issues, shortly after its release the owners found a new company with the funds raised by this joint venture. It was first called Quintessential Consultants Inc. (QCI), later renamed to American Megatrends Inc. (AMI) to keep the "AMIBIOS" acronym. The new company then acquired AMIBIOS from Access Methods next year.<ref>https://www.youtube.com/watch?v=5jYX3sL08Xs</ref>


== List of known versions ==
== List of known versions ==
All versions made before the [[AMI Plus BIOS]] were released by Access Methods and therefore had their copyright, although some of these versions later received updates under American Megatrends ownership, and these newer versions had their copyright instead.
All versions made before the [[AMI Plus BIOS]] were initially released by Access Methods and therefore in most cases had their copyright, although some of these versions later received revision updates under the American Megatrends ownership, therefore older versions could occasionally also be seen with newer copyright.  


Most instances of versions from [[AMIBIOS 2.2x]] to [[AMIBIOS 6]] and [[AMIBIOS 07.00.10]] can be identified by the date in the identification string (often shown at the bottom of the POST screen), as these dates were fixed to the initial release date of the version. However, these dates were occasionally modified by [[wikipedia:Original_equipment_manufacturer|OEMs]] to reflect the ROM compile date instead, especially until [[AMI WinBIOS|AMI WinBIOS (AMIBIOS 4)]]. On AMIBIOS 07.00.xx and all later versions (excluding 07.00.10), the date in the identification string indicates the ROM compile date instead and therefore cannot be used to determine the AMIBIOS version.
Most instances (ROMs) of all versions from [[AMIBIOS 2.2x]] to [[AMIBIOS 6]] and also the [[AMIBIOS 07.00.10]] can be identified by the date shown in the identification string (which is often shown at the bottom of the POST screen), as these dates were fixed to the initial release date of the version. However, these dates were occasionally modified by [[wikipedia:Original_equipment_manufacturer|OEMs]] to reflect the ROM compile date instead, especially until [[AMI WinBIOS|AMI WinBIOS (AMIBIOS 4)]]'s release. On AMIBIOS 07.00.xx and AMIBIOS 8, the date in the identification string indicates the ROM compile date instead and therefore cannot be used to determine the AMIBIOS version.


'''Notice:''' Due to a lack of information and references, the names for all versions released before the AMI Hi-Flex BIOS are assumed based on little and unofficial information. When more information is discovered, these will be corrected.
'''Notice:''' Due to lack of information and references, the names for all versions released before the AMI Hi-Flex BIOS are assumed based on little and unofficial information available. When more information is available, these will be corrected.
{| class="wikitable" style="width:100;%"
{| class="wikitable" style="width:100;%"
!Version name
!Version name
Line 19: Line 19:
!POST screen (if available)
!POST screen (if available)
!Notes
!Notes
|-
|[[AMIBIOS Rev-X2-03|''"Rev-X2-03" (AMIBIOS 2.03?)'']]
|Likely 1985 or early 1986
|[[File:AMIBIOS_Rev-X2-03_POST.png|300px]]
|Possibly the earliest known version. AMIBIOS 2.03 is an assumed name.
|-
|-
|[[AMIBIOS 2.2x|AMIBIOS 2.2x(?)]]
|[[AMIBIOS 2.2x|AMIBIOS 2.2x(?)]]

Revision as of 12:01, 27 July 2024

AMIBIOS is a personal computer BIOS developed by AMI (American Megatrends). It was released in 1985 by Access Methods Inc. as one of the earliest fully and legally IBM PC-compatible BIOS for its clones. As the IBM PC's BIOS was copyrighted and early implementations based on its documentation suffered from legal trouble, companies like Phoenix and Access Methods reverse engineered their own solutions under a clean room design to avoid such trouble, with AMIBIOS being the latter's solution (shortly released after the former's PhoenixBIOS). It was then acquired by American Megatrends Inc. next year.

While it is still used on some legacy computer systems (such as the ones based on the Vortex86 SoC), it was phased out on most consumer platforms in the early 2010s in favor of UEFI firmware such as Aptio (also by AMI), InsydeH2O, and Phoenix SecureCore. Although earlier instances of Aptio contained an embedded version of AMIBIOS 8 as a component module for legacy boot (CSM). However, since CSM was discontinued by Intel in 2020, the module is no longer present.[1]

Acquisition from Access Methods Inc.

Main page: American Megatrends

Access Methods Inc., a joint venture by Subromanian Shankar and Pat Sarma, released the first version of AMIBIOS in 1985.[2] Due to legal issues, shortly after its release the owners found a new company with the funds raised by this joint venture. It was first called Quintessential Consultants Inc. (QCI), later renamed to American Megatrends Inc. (AMI) to keep the "AMIBIOS" acronym. The new company then acquired AMIBIOS from Access Methods next year.[3]

List of known versions

All versions made before the AMI Plus BIOS were initially released by Access Methods and therefore in most cases had their copyright, although some of these versions later received revision updates under the American Megatrends ownership, therefore older versions could occasionally also be seen with newer copyright.

Most instances (ROMs) of all versions from AMIBIOS 2.2x to AMIBIOS 6 and also the AMIBIOS 07.00.10 can be identified by the date shown in the identification string (which is often shown at the bottom of the POST screen), as these dates were fixed to the initial release date of the version. However, these dates were occasionally modified by OEMs to reflect the ROM compile date instead, especially until AMI WinBIOS (AMIBIOS 4)'s release. On AMIBIOS 07.00.xx and AMIBIOS 8, the date in the identification string indicates the ROM compile date instead and therefore cannot be used to determine the AMIBIOS version.

Notice: Due to lack of information and references, the names for all versions released before the AMI Hi-Flex BIOS are assumed based on little and unofficial information available. When more information is available, these will be corrected.

Version name First release date POST screen (if available) Notes
AMIBIOS 2.2x(?) 1986 The name is assumed based on information from the unofficial MR BIOS website[4] and therefore may not be correct.
AMI Plus BIOS(?) 1987 The name is assumed based on information from the unofficial MR BIOS website[5] and may not be correct. Unofficially also called the AMI Pre-Color BIOS due to its monochrome setup utility, which came out before the AMI Hi-Flex BIOS with its colorful utility.
AMI Hi-Flex BIOS 1990 Not to be confused with the Hi-Flex Setup Utility on AMIBIOS 6 and 07.00.10, which was named after it. Unofficially also called AMI Color BIOS due to its colorful setup utility. Likely and internally also called AMIBIOS 3, although unconfirmed.
AMI WinBIOS (AMIBIOS 4) 1993 Often referred to as the AMI WinBIOS, not to be confused with the WinBIOS Setup Utility on AMIBIOS 6 (which was named after it).
AMIBIOS 5 1994 Visually almost identical to the AMIBIOS 4, although contains new features and likely also initial bug fixes.
AMIBIOS 6 1995
AMI eBIOS Version 1 Unknown Not available. Assumed to exist due to the existence of the eBIOS 02.00.xx.
AMIBIOS 07.00.xx / 07.00.00 1999 Known as both AMIBIOS 07.00.xx and 07.00.00. Likely a pre-release version of AMIBIOS 8, although was used on various retail systems in 1999 and the early 2000s. Not to be confused with the AMIBIOS 07.00.10.
AMI eBIOS 02.00.xx 1999 or 2000 Assumed to be a variant of AMIBIOS 07.00.xx for embedded systems.
AMIBIOS 7 (07.00.10) 2001 Assumed to be an update based on the AMIBIOS 6 codebase. Not to be confused with the AMIBIOS 07.00.xx/07.00.00, which is based on a newer codebase.
64-Bit AMIBIOS Version 1 2001(?) Not available. Assumed to exist due to the existence of the 64-Bit AMIBIOS 02.00.00.
AMIBIOS 8 2001 Last commercial version of the AMIBIOS. Most likely the final product for AMIBIOS 07.00.xx/07.00.00. Although first released in 2001, it was not widely used until a couple years later.
64-Bit AMIBIOS 02.00.00 2003(?) Not available. Likely the predecessor for the AMI Aptio, partly based on AMIBIOS 8 or 07.00.xx. Only known instance is on the SuperMicro MBD-i2DML-8G2-O motherboard.
AMIBIOS 9 Unknown Not available. Used in Microsoft Hyper-V. Assumed to be the name given to the BIOS component for CSM mode in AMI Aptio.

ROM identification string

The ROM identification string was first introduced with AMIBIOS 2.2x and is often located at the bottom left of the POST screen. With this string, many useful details regarding the BIOS ROM can usually be gathered, such as the ROM size, chipset, motherboard manufacturer and sometimes even the AMIBIOS version. The string is formatted into sections with each containing different information regarding the ROM. The known codes for these sections are listed in the list of codes for BIOS strings (also available at the bottom of this page). The string format has been changed various times with some new releases of AMIBIOS.

AMIBIOS 2.2x

MMMM-SSSSSS

  • MMMM: Manufacturer/OEM identification code
  • SSSSSS: AMIBIOS version release date

Example string: 1406-061286

This string is for an AMIBIOS 2.2x version released on June 12, 1986 ("061286") for Flying Triumph Co. Ltd. ("1406").

AMI Plus BIOS

DCCC-MMMM-SSSSSS-KK

  • D: CMOS setup type
    • Note: This section can also be two characters long for "DE" if the ROM contains both built-in diagnostics and an extended setup.
  • CCC: Chipset type
  • MMMM: Manufacturer/OEM identification code
  • SSSSSS: BIOS version release date
  • KK: Keyboard controller ID (with second character indicating the model).

Example string: D286-1277-043089-K0

This string is for an AMI Plus BIOS version released on April 30, 1986 ("043089") with built-in diagnostics ("D") for a machine with a discrete logic chipset for 80286 ("286") and a default/unknown keyboard controller (K"0") for Trangg Bow Co. ("1277").

AMI Hi-Flex BIOS and later versions

CR-VVVV-00MMMM-FFFFFFFF-SSSSSS-DDDDDDDD-Project-Y2KC-K

  • C: Processor architecture
  • R: ROM size
  • MMMM: Manufacturer/OEM identification code
  • FFFFFFFF: BIOS feature identification
    • Usually "00101111" which is the default.
  • SSSSSS: BIOS compile date (AMIBIOS 07.00.xx and 8) or the AMIBIOS version's initial release date (all other versions)
    • Note: Even on versions using the initial release date, this section was occasionally modified by the OEM to reflect the ROM release date instead.
  • DDDDDDDD: BIOS identifier (usually the chipset)
  • Project: internal BIOS project ID
    • Only used on later revisions of AMIBIOS 6 and later versions.
  • Y2KC: unknown, most likely Year 2000 compatibility indicator
  • K: Keyboard controller ID

Example string: 61-0530-001169-00101111-071595-440BX/ZX-1AAET006-R

This string is for a 05.30 version ("0530") 128 KB ("1")* size AMIBIOS 6 ROM ("071595", initial release date for AMIBIOS 6) for 686 architecture processors ("6") with Intel 440BX or ZX chipset ("440BX/ZX") and an AMIKEY '94 clone keyboard controller ("R") for project ID 1AAET006 of MSI ("1169").

*The BIOS ROM size is actually 256 KB in this specific case, the 128 KB size specified in the string is an error. This also means the string is not always fully accurate, although mostly is.

List of known codes for sections of the ROM identification string

Click "Expand" to view.

  1. ↑ https://www.intel.com/content/www/us/en/content-details/630266/removal-of-legacy-boot-support-for-intel-platforms-technical-advisory.html | Note: Although this document was published in 2023, it clearly mentions legacy boot being discontinued in 2020.
  2. ↑ https://twit.tv/shows/triangulation/episodes/226
  3. ↑ https://www.youtube.com/watch?v=5jYX3sL08Xs
  4. ↑ https://mrbios.com/techsupport/award/postcodes.htm | "AMI BIOS 2.2x" section
  5. ↑ https://mrbios.com/techsupport/award/postcodes.htm | "AMI Plus BIOS" section
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This page was last edited on 27 July 2024, at 12:01.