Hi everyone,
I've seen there have been lots of discussion on the ML lately. Great! :) After reading through all the mails I have some thoughts that I'd like to share.
The GNU issue: I think we should wait, atleast until we know what the BIOS is going to be like. There could be some benefits of being a part of GNU, but I believe there are also some disadvantages, such as loosing part of the freedom (actually).
There have been talks about what the BIOS should do and support. One opinion is that it should be extremly small and only support loading in a bootloader, and never be touched again. Another may be to support older OS'es using 16-bit INTs.
As I envision it, the BIOS functionality should be rather big. It shall support all hardware attached to the motherboard, and also other hardware, through their own BIOS. This way programmers of operating systems won't have to worry to much about the hardware part. You may think of it as a HAL (Hardware Abstraction Layer) if you wish.
I think the reason that many programmers have avoided using BIOS routines instead of their own hardware routines is that they don't know in what way the BIOS works. It could be really badly implemented and be really slow. But when the sourcecode is free, they will be able to read the code and see that these routines are actually highly optimized and probably couldn't be done any better. (And if they could, they should do so and send in the patches to openbios.org :-).
When it comes to supporting old 16-bit OS'es I am personally not interested in supporting them at this time. We don't want any crappy 16-bit OS'es anyway! I think the BIOS should be 32-bit and use protected mode (flat) all the way through. And if we really, really need to support 16-bit some day, it will be easy to switch back to real mode and implement the necessary INTs then.
Though I think we should support every existing 32-bit (pmode) interface, such as BIOS32 and VESA 2.0 protected mode interface (the VESA stuff is really not up to us, but to the graphicscard manufacturers).
Some people have talked about OpenFirmware (IEEE 1275) support. This sound like a good idea to me, but since I don't really know what that requires from the BIOS, I can't make any comment on it. I think I will read through the homepage later (http://playground.sun.com/1275/home.html). Although I do know that this would require Forth support, which would be a good thing, since I believe the PCI specification requires BIOS code in Forth for PCI devices. (On the other hand using Forth is said to be big and slow, so I don't know...)
Joel Mansford mentioned that you could have the BIOS setup program run from your favorite OS, which seems like a good idea to me. Then it could be very good looking, and vouch for easy tweaking of the BIOS. Preferably there should also be a complementary setup inside the BIOS, incase the HD breaks down or whatever.
Concerning hardware compability, I think it will suffice to support newer PCIset computers to begin with. That would pretty much mean Pentium and upwards. This is, as I see it, not a big problem at this time. And when we (or someone else) wants to support older hardware (386/486/non PCI) that shouldn't be all to hard when we got a working BIOS. This also implies that I don't think any specific embedded design features should be made at first.
I also, like many other here, think that we should support as many booting devices as possible. Perhaps we should begin by supporting floppy and IDE, and then move on to other things, such as network and USB and so on. This would be real easy to implement later, due to the modular design.
That is something I believe that _everyone_ agrees of; that OpenBIOS should use a highly modular design. This will bring several obvious advantages. I have though of three different places where the modularity will take place. First is the sourcecode, where many different pieces of hardware can be supported via preprocessor directives, and separate sourcefiles. Then just before flashing the BIOS into ROM, there could be different modules that the user could choose between to change functionality, but without having to recompile. Lastly there could be some runtime autodetection of hardware. I think this last thing should be used very moderately, if at all.
If you are still reading this, I want to apologize for this quite large post (didn't mean to do it... ;)
Best regards, Niklas Ekström