Booting with Grub

[Phil Schaffner]

On Tue, 2004-11-30 at 10:16 -0700, Guy Fraser wrote:
> 
> Phil Schaffner wrote:
> 
> >On Sat, 2004-11-27 at 20:01 -0800, Vadim wrote:
> > 
> >>On a similar note.
> >>Why did we stop supporting LILO?
> >
> >Because GRUB is more powerful, has a shell, doesn't have to be
> >reinstalled every time the config is changed?
> >
> No, but install a new drive and with no errors you may get nothing but a 
> blinking
> cursor after selecting your entry.

I remember several instances of "LI" or "LI..." followed by repeated
numbers (like 02 02 02 ... IIRC) ad infinitum.

> The documentation for grub does not seem explain how drives are ordered or
> how to list the order in which they are detected. Mapping drives seems like
> driving in the dark without headlights on a moonless night.

But a least you can get a steering wheel (boot from a grub floppy) and
pick up a stick to probe around with ("find" command in grub shell).

> Can you point me and the rest of the people suffering from this problem 
> to some
> enlightening information on how to configure grub from a rescue disk so 
> that it
> will work after installing an SATA, SCSI or RAID drive. In bugzilla 
> there are
> hundreds of bugs marked as "NOTABUG" with a variety of issues similar to
> this. The "fixes" for this type of problem appear to be quite 
> mysterious, and
> without reasonable explanation to why someone did what they did to make it
> work.

There have been some extensive threads on getting grub configured, but
some better documentation would certainly help.  It is difficult to
generalize the techniques one can use when grub is not working properly,
and to cover all the variations in possible drive mappings between BIOS,
CMOS setup options, and kernel device names.

> I had to reinstall FC3 and reorder the drives in the advanced boot 
> config to
> make it work. Bandwidth and time required to reinstall and get all the 
> updates
> again aside, this is not a reasonable way to add SATA drives to a machine.

Probably could have saved the reinstall by spending the time figuring
out the required device.map using the grub shell and then fixing it in
rescue mode, but I haven't had to tackle that particular problem yet.
Expecting my first SATA machine this week.  (Times have been lean of
late.)

> Lilo may not have a shell, but it does not add ambiguity to which drive is
> which. I don't see how being able to mess around in your boot loader
> during boot is of any more help. All I used to do was boot a rescue disk
> edit lilo.conf, run lilo and reboot, no big deal. Three days of messing
> around struggling through "info grub" and searching bugzilla, is not
> intuitive.

So install LILO and away you go (until/unless it gets dropped as the
"depreciated" status indicates).

> If grub was more intuitive, and not encumbered by "magic" device mapping
> your assessment might be correct. But with no apparent documentation on
> how to properly modify "device.map", or even if it is the right file to 
> modify,
> it is almost a futile effort to modify the grub config by hand.

Again, some better documentation might help.  An example of debug
technique:

http://www.redhat.com/archives/fedora-list/2004-May/msg02647.html

> 
> >Good old LILO is still there in the base distribution if you want to use
> >it.  Quite a few people still seem to like it, or maybe old habits die
> >hard.
> >
> >Phil

Forgot the smiley emoticon.  :-)

Thought this might start a religious war.

> >
> Lilo is a good boot loader, and that is all it is good for, but thats 
> what it was
> meant to do.

Used LILO [mostly] happily for years and was not an early adopter of
GRUB, but both have their good/bad points.  I use GRUB now for its good
points, and because it is the default.

> Most people don't need access to a shell that lets them muck
> around before the system boots, most people just want to select an 
> option if
> they have a multi boot system or different kernels for testing purposes. 

Or perhaps many people have not taken the time to figure out how useful
the GRUB shell can be for debugging problems.

> Too
> bad lilo can't be installed as the default boot loader.

Doubt we're going to go back, but at least LILO should remain an option
for those who prefer it.  Perhaps a Bugzilla RFE is in order?

> According to bugzilla there are hundreds of complaints about grub causing
> problems that are not bugs, but can not be solved intuitively by modifying
> a single file and running a simple command to update the boot configuration.
> 
> My opinion is that either GRUB is poorly designed, too complex for most
> users, or needs good {not info based} documentation, that explains how to
> map real devices to the logical devices used in the menu.lst file. Or grub
> should not internally rearrange logical device maps when new devices are
> added as it appears to be doing.

Would certainly be better if grub did a better job of "guessing" the
same device ordering at boot time that is seen under Linux kernel.
Info-based vs man page is likely to start another long discussion.

Phil