Re: Can Grub start Windows XP from "other" partition

[Ulf Zibis]

Am 23.11.2012 05:20, schrieb Felix Miata:
> On 2012-11-23 04:19 (GMT+0100) Ulf Zibis composed:
>
> > > Maybe it could be done with XXCOPY while booted to a maintenance system, but 
> > > not by a partition
> > > clone. Registry modifications would be required as well as adjusting boot.ini.
>
> > Well, but XCOPY (I guess you mean the one with one X)
>
> Two: XXCOPY.

Ah, I've found it, thanks. But I suspect, if XXCOPY would copy the boot sector of the original 
partition, which I think is required to boot from the "clone". I still can't imagine, what would 
speak against normal partitioning cloning, in simplest via dd. But yes, a registry tweak on a not 
booted system should be necessary.

> > > Windows can be booted by any primary partition that contains NTLDR, if it is an 
> > > unhidden
> > > partition, and there no other Windows native unhidden primary partitions.
>
> > I have a different experience, behind the one, which is booted, other visible 
> > primaries are allowed,
> > see my last comment below.
>
> ...
>
> > > Can't do that. Once chainloaded, you have to use the Windows boot menu from a 
> > > properly constructed
> > > boot.ini. This will be necessary if you make only one primary to be used as C:. 
> > > You only put two
> > > Windows stanzas in Grub's menu if you have two different primaries that could 
> > > be C:.
>
> > ... + edit the grub.cfg to add the hidden (+ makeactive) commands, because 
> > grub-update would not do
> > that automatically. Grub seems to assume, that the the 2nd Windows should run 
> > as e.g. D:. Then there
> > is no need to hide the 1st.
> > Right?
>
> 2nd Windows where? D: will never be a native partition on a first HD primary.

From Windows setup it is possible to install another Windows on same disk in another primary 
partition. This 2nd Window's systemdrive then would be D:, as C: is already assigned to the 1st 
unhidden Windows native partition, which is still visible. Such configuration would be detected by 
update-grub, so both Windows installations appear in the Grub menu, and both could be successfully 
booted via Grub's chainload. But if the 2nd Windows installation was not originally installed to D: 
, then this Window instance would fail or/and corrupt the 1st at some point.

> Do you know what makeactive does? Are you sure it does what you need or want 
> done?

I Think I know, it alters byte 0 of the partition descriptor in MBR from 0x00 to 0x80. Then the 
generic boot loader in MBR or Grub would chainload the bootsector of that partition.

> > > Windows cannot boot a system with more than one visible native type primary per 
> > > HD. In a single HD
> > > system, D: will always be a logical, and C: will be the one and only visible 
> > > primary.
>
> > Hm, that confuses me totally. See the following partitions I have on another 
> > disk, no Grub or Linux
> > installed:
> > sda1: NTFS **boot** ---
> >    Windows XP installation
> > sda4: NTFS **none** --- Data
> > sda3: extended **lba**
> > sda5: FAT32 **none**-- - Backup
> > sda2: Compaq **diag** --- Thinkpad Recovery (physically at the end of the of 
> > the harddrive)
>
> > All partitions are visible and I can perfectly boot Windows from sda1.
>
> I can't respond without knowing the partition type bytes for all of them, and the Windows version. 
> I may also need to see the actual MBR table entries, as that order is non-standard and apparently 
> out of order. I might even need to copy that whole MBR sector to a disk to see what's really going 
> on there.

The unusual order is caused by the preinstalled recovery partition, which is the 2nd after the 
system partition, even if physically at the end of the HD, thusly installed by the computer vendor, 
still before additional partitions are added by the user.
All Windows version here are XP.

Here dumps from 2 of my HD's, utilizing sfdisk:
----------
# partition table of /dev/sda
unit: sectors

/dev/sda1 : start=       63, size= 48821472, Id= 7, bootable
/dev/sda2 : start=304214400, size=  8361360, Id=12
/dev/sda3 : start= 48821535, size= 37784880, Id=83
/dev/sda4 : start= 86606415, size=217600425, Id= 5
/dev/sda5 : start=156232188, size= 48837537, Id= 7
/dev/sda6 : start=205069788, size= 99137052, Id= 7
/dev/sda7 : start= 86606541, size= 69625584, Id= 7
----------
# partition table of /dev/sda
unit: sectors

/dev/sda1 : start=       63, size= 69625647, Id= 7, bootable
/dev/sda2 : start=147903840, size=  8391600, Id=12
/dev/sda3 : start= 89994240, size= 57909600, Id= f
/dev/sda4 : start= 69625856, size= 20367360, Id= 7
/dev/sda5 : start= 89994303, size= 57909537, Id= b
----------