Boot bootmanager - and HPFS GRUB

[Ilya Zakharevich]

1) Does anybody know how to boot bootmanager? (I mean, without
installing it to a real primary partition?)

My conjecture is that it may work from a virtual hard drive. If
so, then I would install bootmanager to a virtual hard drive (e.g.,
from DOS), then load the drive image using MEMDISK (or Grub4dos),
and "boot from a partition on this harddrive".

Hmm, I see problems: one is that this boot would use the EXISTING
information from the "real drives"; but how would one WRITE this
information? I suppose FDISK would not allow me to write the boot
options if it cannot see BootManager installed...

The second problem is that creation of this virtual drive MIGHT mix
up drive-letter assignment. But it should not if BootManager is
the only primary partition on the virtual drive...

2) Does anybody has working HPFS-Stage1.5 for GRUB (one which would
allow GRUB to load from HPFS partition)...

Thanks,
Ilya

[Valery V. Sedletski]

Ilya Zakharevich wrote:
> 1) Does anybody know how to boot bootmanager? (I mean, without
> installing it to a real primary partition?)
>
> My conjecture is that it may work from a virtual hard drive. If
> so, then I would install bootmanager to a virtual hard drive (e.g.,
> from DOS), then load the drive image using MEMDISK (or Grub4dos),
> and "boot from a partition on this harddrive".
>
> Hmm, I see problems: one is that this boot would use the EXISTING
> information from the "real drives"; but how would one WRITE this
> information? I suppose FDISK would not allow me to write the boot
> options if it cannot see BootManager installed...
>
> The second problem is that creation of this virtual drive MIGHT mix
> up drive-letter assignment. But it should not if BootManager is
> the only primary partition on the virtual drive...
>

Did not tried that, but it is probably, possible. The OS/2 bootmanager
loads from a primary partition, but its binary image takes only 14 Kb,
the extra space is empty. If I correctly understood, the newer versions
(from Aurora and newer OS/2 versions) take the drives list from LVM DLA
tables, so they aren't stored on the bootmanager partition. So, you can
extract the BM from its partition (it has its own boot sector, which is
like FAT one actually). For example, it can be taken from DFSee
distribution as a dfsibmgr.img file. I'm pretty sure that you can load
it at 0x7c00 physical address, and jump to its beginning.

> 2) Does anybody has working HPFS-Stage1.5 for GRUB (one which would
> allow GRUB to load from HPFS partition)...

I kinda, have :) I've written a HPFS backend for FreeLDR, it could be
ported to GRUB with minimal changes (as FreeLDR is GRUB based,
actually). It has some problems, but loads files from HPFS pretty well.
The sources are at Sourceforge osFree repository, if you're interested.

You can take the binaries from my ftp
(ftp://valerius.osfree.tk/incoming/freeldr/), if you want.

BTW, FreeLDR can be installed on the same HPFS or JFS partition, which
is bootable for OS/2, it can be loaded like os2ldr from that partition.
(The best way is to boot it as another os2ldr version from os2ldr.ini menu).

>
> Thanks,
> Ilya

[Valery V. Sedletski]

Valery V. Sedletski wrote:
>For example, it can be taken from DFSee
> distribution as a dfsibmgr.img file. I'm pretty sure that you can load
> it at 0x7c00 physical address, and jump to its beginning.
>

More exactly, the BM bootsector is loaded first, then it loads the
remainder of the 1st 14 Kb of the BM. So, it requires the hard disk
access for that. So, yes, you can use emulated hard disk partition
(using memdisk of GRUB4DOS). The only needed thing is to fill the boot
sector BPB first with actual values.