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GRUB will boot BeOS by chainloading the partitions own stage 1.5 boot block, IIRC. Its definately been able to boot it - somehow or other - for years, as I've done it, frequently.

Well yes, obviously. But then we'd have to write a stage 1.5 boot loader for GRUB to chainload.

Vanders, I'm sure you know this, so just so no one gets the wrong idea here: GRUB doesn't have to understand B(e)FS to boot BeOS or Haiku. You simply use GRUB's chainload feature, as described in
http://www.osnews.com/files/syllable-install.html

This way GRUB loads and hands off to BeOS/Haiku's loader which is embedded in the partition's own boot record. You can use the command 'makebootable', but the BeOS (and future Haiku) installer should already have done that for you. (This is not BeOS's MBR menu known as 'bootman' - two separate things. Bootman, if you choose to install it, loads the partition boot record code put there by 'makebootable'.)

The only reason for GRUB to have intrinsic knowledge of a certain filesystem is to host GRUBs menu settings and additional components -within- the filesystem of a specific partition, like the one you've got Linux or Syllable on. Without this intrinsic knowledge of a certain filesystem, a boot menu can't fit much more than chainloading in the tiny space of a disk's Master Boot Record. In my opinion chainloading is cleaner than sort of spilling over into a partition, but people seem to enjoy bloat. ;P The only good reason I can see for doing it might be being able to load different operating systems with multiple presets of boot parameter for each.

Yes. However the discussion originally started with the question of if you could now install Syllable on a BFS filesystem instead of AFS. My point is this: ignoring the Syllable block cache issues, we would require a GRUB that is capable of booting BFS itself as Syllable Desktop has a multiboot kernel and GRUB is a multiboot loader. Chain loading the Haiku BFS bootloader is no use for Syllable, even if we ported it.

If and when we solve the block cache issues, we can simply use the BFS/SkyFS stage1_5 patches written by Robert for use with SkyOS.

You don't need BFS support to boot a BFS partition. How else would any PC boot BeOS at all? Even the Windows bootmanager can boot BFS partitions. For that to work, the first block of the partition contains the actual boot code (which then contains support for BFS). That code gets written to the partition if you invoke "makebootable" in BeOS. I think the feature of the bootmanager is called "chain loading". (chainload=1 in the grub config? Just be careful to not make logical partitions "active".)

Yes, it contains the boot loader for BeOS. This entire discussion is about booting Syllable from a BFS partition. The BeOS/Haiku boot loader that may or may not be present on the partition (if you formatted the partition from Syllable there is certainly no bootloader installed) is no help here.

A lot of people seem confused about what exactly the boot loader is and how it all works. When I say "GRUB can not boot from a BFS partition" I mean exactly that. GRUB can chainload another bootloader that can do it, of course it can, but that's a totally separate boot loader that you just happen to load with GRUB. GRUB is not booting from the BFS partition at all. It's loading a totally different bootloader that in this particular instance happens to be system specific.

Syllable uses GRUB as its bootloader. For Syllable to be able to boot from a BFS partition, GRUB must be capable of booting from BFS: it must have a bfs_stage1_5 loader that it can embed into the filesystem.

SkyOS uses GRUB as the bootloader and already has the ability to do this. In fact Robert had to modify BFS slightly so that GRUB could embed the stage1_5 file correctly. When and if Syllable can be installed on a BFS partition we will almost certainly use the same GRUB patches that Robert wrote for SkyOS.