Product specifications

Comparison of different BIOS implementations
AwardBIOS AMIBIOS Insyde SeaBIOS
License Proprietary Proprietary Proprietary LGPL v3
Maintained / developed No Yes Yes Yes
32-bit PCI BIOS calls ? ? ? Yes
AHCI Yes Yes Yes Yes
APM Yes Yes Yes (1.2) Yes (1.2)
BBS Yes Yes Yes Yes
Boot menu Yes Yes Yes Yes
Compression Yes (LHA) Yes (LHA) Yes (RLE) Yes (LZMA)
CMOS Yes Yes Yes Yes
EDD Yes Yes Yes Yes (3.0)
ESCD Yes Yes ? No
Flash from ROM ? Yes ? No
Language Assembly Assembly Assembly C
LBA Yes (48) Yes (48) Yes Yes (48)
MultiProcessor Specification Yes Yes Yes Yes
Option ROM Yes Yes Yes Yes
Password Yes Yes Yes No
PMM ? Yes ? Yes
Setup screen Yes Yes Yes No
SMBIOS Yes Yes Yes Yes (2.4)
Splash screen Yes Yes (PCX) Yes Yes (BMP, JPG)
USB booting Yes Yes Yes Yes
USB hub ? ? ? Yes
USB keyboard Yes Yes Yes Yes
USB mouse Yes Yes Yes Yes
IBM published the entire listings of the BIOS for its original PC, PC XT, PC AT, and other
contemporary PC models, in an appendix of the Technical Reference manual for each machine type.
The effect of the publication of the BIOS listings is that anyone can see exactly what a definitive BIOS
does and how it does it. Phoenix Technologies was the first company to write a fully compatible and
completely legal BIOS through clean-room reverse engineering.
New standards grafted onto the BIOS are usually without complete public documentation or any BIOS
listings. As a result, it is not as easy to learn the intimate details about the many non-IBM additions to
BIOS as about the core BIOS services.
Most PC motherboard suppliers license a BIOS "core" and toolkit from a commercial third-party,
known as an "independent BIOS vendor" or IBV. The motherboard manufacturer then customizes this
BIOS to suit its own hardware. For this reason, updated BIOSes are normally obtained directly from
the motherboard manufacturer. Major BIOS vendors include American Megatrends (AMI), Insyde
Software, Phoenix Technologies and Byosoft. Former vendors include Award Software and Microid