Open source BIOS for 80286 (and higher)

[Ruud]

In the past I created my own XT BIOS and we probably all know the Anonymous BIOS and Sergey's BIOS, used for his own and other projects. The latest thread about the original source of the Anonymous BIOS made me wonder if there was ever made a try to create an open source BIOS for the 80286, and maybe for the 80386 and 80486?

 

[sqpat]

I actually asked this question in a retro computer related discord yesterday. I think there weren't any examples, but the difference between an AT bios and a XT bios is comparatively small. However a sufficiently advanced 286 (or later) chipset may have memory and cache and I/O controllers supporting IDE, LIM EMS, XMS, ROM Shadowing, Cache (writeback?), clock dividers, etc - then it becomes a lot more complicated and chipset dependent. It would definitely be cool if such a thing existed. There's a lot of documentation out there for certain chipsets and the AT is definitely well documented too.

 

[mmruzek]

Of interest regards this topic is the AT BIOS Kit written in C by Annabooks. The files for the AT are floating around out there... There is a similar BIOS for the PC, but I have never been able to locate those files.

AT Bios kit : the comprehensive guide to creating an AT Bios in C : Foster, John O : Free Download, Borrow, and Streaming : Internet Archive

Disk contents: http://www.archive.org/download/ATBIOS_Kit_Nov89/ATBIOS.ZIP http://www.archive.org/download/ATBIOS_Kit_Nov89/ATBIOS_UNPACKED.ZIP

archive.org