Bootloaders (LILO, GRUB, GRUB2, MS windows) - compare/contrast etc

[Richard Owlett]

Background: I've got a machine with mucked up dual boot from
attempting to get full install on a USB from a Ubuntu 10.10
live cd. GRUB2 ended up on my hard drive, all else on USB
stick. Got confusing and confused(responder didn't pay
attention to differences between Legacy Grub and Grub2)
responses on their forum to either removing Grub or forcing
it to only attempt to boot from the only OS existing on the
hard drive (WinXP Pro SP3 - it will leave eventually).

Needed: Carnal knowledge of boot process and first "n"
sectors of drive:

Question: Any pointer to good site covering all? Google
leads to various pages covering subjects individually and
written by different authors at different times with
differing audiences in mind.

The only general stuff I have at moment are pdf's of
Slackbasics and Slackbook-2.0.
Between them I've some 50 pages of tangential material to
absorb or refresh. I date from era when one sat in front of
your 11/45 and loaded ~20 instructions from front panel to
read paper tape via TTY which allowed you to load OS from
"high speed"(LOL) reader.

TIA

[Douglas Mayne]

I am a grub user, but I am sticking with version 0.97 until forced to
switch. I'll probably have to learn about the next generation loaders
when EFI/GUID capable loaders. I think grub legacy was/is the most
flexible loader when not requiring those features. Slackware is mostly in
the lilo camp, but grub is available in the "extra" series. I used to
advocate quite often for grub and for learning what the "setup" programs
do "behind your back." That requires understanding basic disk structures
(partition tables, boot sectors, layout, etc.). Theory only goes so far,
and at some point you'll need to experiment. Experimenting can be
dangerous, so be careful and/or have a system that is "expendable."

--
Douglas Mayne

[Aragorn]

On Monday 06 February 2012 17:41, Douglas Mayne conveyed the following
to alt.os.linux.slackware...

> I am a grub user, but I am sticking with version 0.97 until forced to
> switch. I'll probably have to learn about the next generation loaders

> when EFI/GUID capable loaders. [...]

As I understand it, grub-legacy /should/ be able to handle GUID
partition tables.

EFI is another beast altogether because with an EFI, the processor is
already in protected mode - and the other processor cores are also
initialized and in protected mode - before it loads the bootloader. So
that requires a special version of GRUB. ELILO is the EFI equivalent of
LILO.

--
= Aragorn =
(registered GNU/Linux user #223157)

[Richard Owlett]

In a lot of ways we agree. It's taken almost fifty years,
but I'm agreeing more with my professors that more theory is
good theory.

I _was_ experimenting ;/
I thought safely by installing to a removable device. It wasn't.
Now I need more theory to recover from not fully knowing
what details were hidden behind the scenes. I've come across
Linux tools promising to modify, repair, or remove faulty
GRUB installs. But they hide to many details to make me
comfortable.

I gather from the sparse replies to my post that there is
nothing covering the breadth I indicated. I'll have to
narrow my research to GNU GRUB 1.98 and MS Windows' use of
the MBR.
I have two immediate goals:
PREFERRED - remove all of GRUB and restore former booting
ALTERNATE - modify the GRUB install so it only attempts
to launch OS
existing on the hard drive (WinXP Pro at the
moment)
Achieving either will then allow a proper dual boot Linux
install - most likely Slackware or a derivative.

[Douglas Mayne]

One thing I really like about grub is the interactive command line shell.
The parameters can be entered on the fly, for example to initialize the
startup of a specific kernel. It can even work in a generic boot sense to
boot and then dynamically and interactively look for the kernel and
initrd. I have a generic boot cd image online that can be used for that
purpose. I haven't written much about bootstrapping lately, but at one
point I wrote about it about every other day. ;) Apologies if some
information is slightly out of date. These tools have remained consistent
enough during the last few years that the syntax works as it did before.
Unfortunately, the new version of grub abandoned (or changed) some
meanings/definitions. The following is what I have on v0.97.

I found a general tutorial from a few years ago:
http://preview.tinyurl.com/72qrm3l

Here is the post with info about my boot cd image (with source and
disclaimer info):
http://preview.tinyurl.com/2b9j34

In the interim, I had to move the files to save money here. The broken
links should work with these links instead:
http://user.xmission.com/~ddmayne/ddmayne2/grub/v0.97/grub.iso.gz
http://user.xmission.com/~ddmayne/ddmayne2/grub/v0.97/md5sums

HTH

--
Douglas Mayne

[Richard Owlett]

You once wrote, "Test, don't assume something works by
extrapolation."
http://groups.google.com/group/comp.os.linux.setup/msg/86f68934908589ba

The above post addresses a problem I do not have.
OK, already. I may "have it", but it's not the aspect that
bothers me.

I've "GRUB 2" - *NOT* "GRUB LEGACY" on my hard drive.
It's default OS (Ubuntu 10.10) resides on a USB stick.
If the USB stick is plugged in, there is not a disastrous
failure.
I get a menu defaulting to inappropriate OS but allowing
selection of acceptable OS.
!!! *BUT* !!! if USB stick not plugged in, I get
UNACCEPTABLE response.
GRUB goes CLI.
I NEED OS on hard drive to boot if USB stick missing.

BTW - what's my attraction to Slackware? It requires
willingness to address/understand internals.