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Home > Archive > Red Hat Installation > March 2005 > grub error 18
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| Andreas M?ller 2005-03-10, 5:59 pm |
| Hallo all,
I've installed RH Enterprise AS 4 for testing purposes. Currently I'm
getting an annoying error message from grub:
Error 18: Selected cylinder exeeds maximum supported by BIOS
Well, the same error occured with a AS 3 version some time ago. It's
annoying to find grub still broken. Of course the BIOS does not see
all the hd, but who cares. LILO IS capable of booting the system
without any problems. I did not see the option to use lilo instead of
grub during installation (but maybe it exists). I have to fix it
manually now. So can anyone tell whether grub will get fiexed one day
in the future? It has some nice features, but becomes useless when it
won't boot the system.
Why will lilo boot the system and grub not?
Thanx in advance,
Andreas
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| Andreas M?ller wrote:
> Hallo all,
>
> I've installed RH Enterprise AS 4 for testing purposes. Currently I'm
> getting an annoying error message from grub:
>
> Error 18: Selected cylinder exeeds maximum supported by BIOS
>
> Well, the same error occured with a AS 3 version some time ago. It's
> annoying to find grub still broken. Of course the BIOS does not see
> all the hd, but who cares. ...
GRUB cares. It relies on the BIOS to locate the sector where /boot
resides. It is designed this way; it is not "broken".
> ... LILO IS capable of booting the system
> without any problems. I did not see the option to use lilo instead of
> grub during installation (but maybe it exists). I have to fix it
> manually now. So can anyone tell whether grub will get fiexed one day
> in the future? It has some nice features, but becomes useless when it
> won't boot the system.
>
> Why will lilo boot the system and grub not?
LILO encodes it's needed info when installed (and while Linux is
running to provide the info) and is why you always have to "refresh"
the info by running lilo.
GRUB does not now and never will operate this way since all it really
needs is the linear sector number where /boot resides (which it gets
from the BIOS at boot). You have an older BIOS that cannot
read/translate CHS/sector numbers beyond 8GB (is my guess).
>From the GRUB docs:
Errors reported by the Stage 2 (the "real" boot loader code)
18 : Selected cylinder exceeds maximum supported by BIOS
This error is returned when a read is attempted at a linear block
address beyond the end of the BIOS translated area. This generally
happens if your disk is larger than the BIOS can handle (512MB for
(E)IDE disks on older machines or larger than 8GB in general).
Even this is not usually a problem but there is no absolute standard
regarding the translation of CHS to LBA and some BIOS routines boink at
8GB because the makers did not allow for the capability (or the need
for it).
All cases I've encontered were fixed with a BIOS flash upgrade but
there are cases (and yours may be one) where this is not possible or
the translation code is "faulty" (no standard, no blame).
This is why it is often suggested that a separate /boot partition be
made that is located within the BIOS's capabilities. There are other
reasons why it's a good idea, but probably not worth a
re-install/repartition _just_ for this test setup. LILO will still
work (because of its design) and I'm not aware of any distro that does
not include it somewhere (though RH has deprecated it since RH7.x,
IIRC). Haven't seen the rpms included with RHEL4.
Just looked. It's lilo-21.4.4-26.1.src.rpm so must be
lilo-21.4.4-26.1.rpm for the binary. Since you seem to be familiar
with it, I would just go with LILO and investigate GRUB's problems
separately.
hth,
prg
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| Andreas M?ller 2005-03-12, 5:50 pm |
| > GRUB cares. It relies on the BIOS to locate the sector where /boot
> resides. It is designed this way; it is not "broken".
O.K. Thanx for the information. It's good to know that it is designed
to work this way.
> All cases I've encontered were fixed with a BIOS flash upgrade but
> there are cases (and yours may be one) where this is not possible or
> the translation code is "faulty" (no standard, no blame).
Yes the problem is due to BIOS. Of course there is no more an update
available for this BIOS. The board is an older one. Finally I know
that grub has to work the way it works and so I'll stay with LILO.
Thanx again,
Andreas
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