[SLE] SuSE Restart vs Shutdown

[Terry Eck]

Yesterday I wanted to boot from a CD so I checked to "restart" option.
The system rebooted and at the correct point I got into the BIOS to make
sure the CDROM would be the boot device. Then when it got to the point
of rebooting the computer ended up in SuSE 10. I then told SuSE to
"turn off the computer", which it did. After powering on the computer
if booted off the CDROM. My question:

Does SuSE somehow force the computer to bypass the boot sequence set
in the BIOS when it is told to "restart"? If so, anyone know how this
is done?

Thanks for any insite
Terry
--
SUSE LINUX 10.0 (i586) -- 2.6.13-15.12-default -- Sun 10/01/06
1:10pm up 17:03, 3 users, load average: 0.50, 0.46, 0.42

[Per Jessen]

Post by Terry Eck
Does SuSE somehow force the computer to bypass the boot sequence set
in the BIOS when it is told to "restart"? If so, anyone know how this
is done?

No, SUSE (nor anyone else) cannot override the boot-sequence set in the
BIOS.



/Per Jessen, Zürich

[Anders Johansson]

Post by Per Jessen

Post by Terry Eck
Does SuSE somehow force the computer to bypass the boot sequence set
in the BIOS when it is told to "restart"? If so, anyone know how this
is done?

No, SUSE (nor anyone else) cannot override the boot-sequence set in the
BIOS.

Assuming you get to the BIOS, this is true. But with kexec, there is
work being done on accomplishing a true "warm boot", where you reboot
without ever touching the BIOS. As I understand it, the kernel simply
shuts down everything, loads the new kernel (if applicable), and
launches it

But since Terry mentioned that he was in the BIOS settings editor he was
already outside the linux kernel, so this is obviously not relevant, so
sorry for mentioning it :)

[Alexey Eremenko]

Actually, SUSE does NOT bypass your BIOS settings, *but* it has 2
bootloaders, one on the CD-ROM and other in the Hard Disk, so you migh boot
from CD-ROM wait for 10 seconds, and if you don't pressed any buttons, it
boot from Hard Disk.

So *watch* carefully what bootloader runs after restart. (and don't blink)

The two bootloaders look the same but have one *big* diffrence - bootloader
on CD has first option to "boot from Hard Disk", while bootloader on Hard
Disk has no such option, because it already booted from HDD.

[m***@safenet-inc.com]

Post by Terry Eck

Post by Terry Eck
Does SuSE somehow force the computer to bypass the boot sequence set
in the BIOS when it is told to "restart"? If so, anyone

know how this

Post by Terry Eck
is done?

No, SUSE (nor anyone else) cannot override the boot-sequence
set in the
BIOS.

Not meaning to insult anyone, but it could be as simple
as inattention.

The default loader screen on the CD looks a lot like the
default loader screen of installed SUSE - that pretty
blue screen with four or five selections in the middle...

If you aren't paying attention, you could imagine you're
looking at the usual installed-SUSE startup selection
screen.
The default action of the screen from the CD is to
load from hard disk, so unless you are paying attention
and override that by selecting one of the other options,
the system loads the preliminaries from the CD (not your
hard disk), waits the few seconds for the timeout,
doesn't get a keypress or mouse-click from you, and
starts the default selection... which is your already
installed SUSE 10.

I've been wrong before.

Kevin

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[Terry Eck]

Post by m***@safenet-inc.com
The default loader screen on the CD looks a lot like the
default loader screen of installed SUSE - that pretty
blue screen with four or five selections in the middle...
If you aren't paying attention, you could imagine you're
looking at the usual installed-SUSE startup selection
screen.

Actually I was trying to boot a live cd of pclinuxos.

I will have to assume the problem was as Anders Johansson states:

"This happens with disturbing frequency on my machine, the BIOS often
doesn't detect a CD or DVD in the player and jumps to the harddisk
directly. It's either a BIOS bug or a problem with my DVD player..."

It just seemed strange at the time that the boot from CD occurred as
soon as I told SuSE to "turn off the computer".

Thanks for all who responded.

Terry
--
SUSE LINUX 10.0 (i586) -- 2.6.13-15.12-default -- Sun 10/01/06
4:05pm up 19:58, 4 users, load average: 0.31, 0.37, 0.47

[m***@safenet-inc.com]

Post by Alexey Eremenko
Actually, SUSE does NOT bypass your BIOS settings, *but* it has 2
bootloaders, one on the CD-ROM and other in the Hard Disk, so you migh
boot
from CD-ROM wait for 10 seconds, and if you don't pressed any buttons,
it
boot from Hard Disk.
So *watch* carefully what bootloader runs after restart. (and don't
blink)
The two bootloaders look the same but have one *big* diffrence -
bootloader
on CD has first option to "boot from Hard Disk", while bootloader on
Hard
Disk has no such option, because it already booted from HDD.

OK, Alexey beat me to it - sorry for the duplicate post.

But it sounds like more than one person has tripped over
the similarity, so I wonder if it would make sense for
SUSE to do something simple to change the appearance of
one or the other selection screen. Either make them two
different background colors, or two different foreground
text colors, or perhaps _move_ the block of selections
on the screen, enough to be obvious... one would be (say)
center-left and the other would be center-right.
Or, on the CD-based boot selector, the first option could
blink while the countdown was on.

Any observations and comments? Or is this just too darn
trivial?

Kevin

The information contained in this electronic mail transmission may be privileged and confidential, and therefore, protected from disclosure. If you have received this communication in error, please notify us immediately by replying to this message and deleting it from your computer without copying or disclosing it.

[Anders Johansson]

Post by Terry Eck
Yesterday I wanted to boot from a CD so I checked to "restart" option.
The system rebooted and at the correct point I got into the BIOS to make
sure the CDROM would be the boot device. Then when it got to the point
of rebooting the computer ended up in SuSE 10. I then told SuSE to
"turn off the computer", which it did. After powering on the computer
Does SuSE somehow force the computer to bypass the boot sequence set
in the BIOS when it is told to "restart"? If so, anyone know how this
is done?
Thanks for any insite

This happens with disturbing frequency on my machine, the BIOS often
doesn't detect a CD or DVD in the player and jumps to the harddisk
directly. It's either a BIOS bug or a problem with my DVD player, I
haven't decided which yet

It is theoretically possible to change BIOS settings from inside an
operating system, for example my thinkpad has a program (for windows)
which changes the password/firgerprint settings. This could be made to
change any BIOS setting, including the boot order. But as far as I'm
aware, there is no such functionality in linux at this time