Grub missing

[Felix Miata]

On 2007/10/26 21:48 (GMT+0200) Mario Vukelic apparently typed:

> On Fri, 2007-10-26 at 14:57 -0400, Felix Miata wrote:

>> Actually that's a common conception rooted in Linux installers' standard
>> non-acceptance of standard MBR code - essentially the same problem Linux
>> people complain about. There's no need in most cases for Grub to be in the
>> MBR. When Linux is installed to accept use of standard MBR code, there can be
>> no damage to Grub or Linux. The only problem with what doz "does to Linux" is
>> Linux's own fault for changing the MBR code in the first place.

> Thanks for the explanation, it was very interesting. But I do not
> understand one thing: isn't it the case that Windows overwrites the MBR
> itself, so in most cases there is no "standard MBR code" available at
> the time Linux is installed?

What it writes is standard code. I've not checked lately, but I'm not sure
versions through XP write it at all as long as when its installer looks at it
it recognizes it as standard MBR code.

What I mean by standard is code whose job it is to find an active primary
partition on the first disk, to which when found it transfers control. This
behavior predates Linux and the bootloaders it spawned by about a decade, and
has changed only as pertains to the early editions' failure to be able to do
its job on disks of more than ~8GiB.

> I frequently install grub in non-MBR locations on computers that have
> Windows installed, and I have played with the "active" flag. It seems to
> me that it never booted Linux just by changing the active partition, but
> I could be wrong of course.

Because of LILO's and Grub's ability to load any partition on any disk,
people take it as meaning there's no need to install any portion of Linux on
a primary partition. Technically that's true, but as a practical matter, in a
doz multiboot environment, not having a universal bootloader that standard
MBR code can transfer control to causes needless difficulty in the form of
rescue boots and boot loader re-installations following doz installations,
and the virtually inevitable doz re-installations.

If you were unable to boot Linux from an active first disk primary, it means
one didn't exist with a functioning bootloader installed on it, not that one
couldn't have existed given an available MBR partition table entry.

I've only once in many years installed a Linux boot loader into the MBR, and
that only because I couldn't figure out a way to tell the brain-dead Lindows
installer not to put it there.

>> Standard MBR code passes control to the "active" (or "startable" or
>> "bootable", 0x80 in the MBR partition table) primary partition on the first
>> disk.

> But being able to boot only from a primary partition on the first disk
> is an unacceptable limitation of the i386 architecture. It just does not
> work anymore.

Oh, but it can for most people. Doz generally shows up with no more than two
MBR partition table entries in use. In those cases, there's no reason not to
use an available MBR table entry for the creation of a partition that will
provide a home for LILO or Grub. Once that's done, the possibilities have few
limits, regardless how many disks are in the system. Once you have created
one with Grub on it, it doesn't even need touching by as many additional
Linux installs as you care to have. Just put each additional install's boot
loader on some other partition, usually it's root, and chainload to it from
the original on the primary. Any text editor can be easily used to add more
stanzas to the menu.lst on the primary, but it isn't necessary except as a
convenience. Grub's command prompt does work just fine to find new Linux
installs to chainload to, and even doz. You can also put it on the MBR of the
additional disks as a form of insurance to facilitate boot when the first
disk dies.

>> When the doz partition is active, it's what control gets passed to,
>> where with modern versions its own boot loader can pass control to another
>> partition, such as one on which Linux and Grub are installed.

> Yeah, I'm doing that, too. It's a simple thing if you know what to do,
> but it's not what I would consider "friendly".

With M$'s market share it has no compulsion to be friendly, but there's no
real reason for that to be an obstacle. Any number of readily available tools
that run in doz can flip those two MBR bits so that the Linux primary is
active instead of the doz.

> But in the end, doesn't it come down to this: all general-purpose
> GNU/Linux distros I have seen for many years managed to preserve the
> bootability of an preexisting Windows installation, or at least offered
> the tools during the install process. Windows just doesn't car and gives
> not even an option not to harm the user.

Such is the expected attitude of a convicted monopolist. It's boot loader is
capable of chainloading of sorts to a non-doz partition, so it's not like it
put forth 0 effort to share.

Like I wrote earlier, the harm it may cause is actually self-imposed - "self"
meaning Linux installation tool defaults. Because they are only defaults, an
informed user can work past their limitations.
-- 
"The basis of our Bill of Rights comes from the teachings
we get from Exodus and St. Matthew, from Isaiah and St.
Paul.	                       President Harry S. Truman

 Team OS/2 ** Reg. Linux User #211409

Felix Miata  ***  http://mrmazda.no-ip.com/