[haiku-development] Re: EFI and GPT

  • From: Philippe Houdoin <philippe.houdoin@xxxxxxxxx>
  • To: haiku-development@xxxxxxxxxxxxx
  • Date: Tue, 9 Apr 2013 14:03:18 +0000 (UTC)

Fredrik Modéen <fredrik@...> writes:

> Hi
> How far have our EFI and GPT support come?
> I see code of EFI in here 
> http://cgit.haiku-os.org/haiku/log/src/add-
> But are that one fully working?
> PS MediaMarkt are not the frendlies if you like to test a USB. Bought a 
> asus vivobook with touch screen and windows 8 (realy nice), not only for 
> Haiku but it would be nice to be able to boot Haiku on it ;)
> //Fredrik

Bought an Asus VivoBook (S300CA) myself too, and while I'm glad your 
question, Fredrik, leads to rename our GPT partition system add-on from 
"efi_gpt" to "gpt", the question remains: how far have our EFI and GPT 
support comes?

From my understanding, neither our current bootmanager / anyboot MBRs 
supports GPT partitions table, and the only solution meanwhile is to somehow 
install Haiku on one of the first 4 (GPT) partitions and use some tools like 
gptsync under Linux to match these 4 GPT entries in the MBR's partition 
There is a patch in #4028 to change our MBR boot code to an hybrid one which 
could support GPT (no more first 4 entries, no MBR/GPT mapping needed), but 
I'm not clear if that would be enough to load Haiku from a GPT-based disk in 
legacy BIOS mode. 
Does our stage2 boot_loader needs to know anything about GPT to locate Haiku 
and the kernel image?

Regarding EFI boot mode, I'm following your branch, Fredrik, but I 
understand that it's not ready and, there, needs to add boot_loader EFI 
platform support, which will interface with the EFI system.

But meanwhile, if one could install Haiku beside others OS without resorting 
to old MBR-based partitions table, it will be already a nice thing.

So, if you guys could enlight me on what is missing, what should be working 
already and what is clearly not ready and not easy task to fix, thanks.

Philippe Houdoin.

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